EPIDEMIOLOGY OF DISEASES OF NAVAL IMPORTANCE IN FORMOSA NavMed 266 BUREAU OF MEDICINE AND SURGERY NAVY DEPARTMENT WASHINGTON, D. C. 19 4 4 PREFACE TO SECOND PRINTING Although some additional information has become available since first publication of this manual, it is not of sufficient importance to change the basic picture significantly. Since the need for an addi- tional printing of this publication has become pressing, it is reprinted at this time without an attempt at revision. December, 1950 TABLE OF CONTENTS Page Foreword iii Chapter I Introduction 1 II Malaria 4 in Filariasis 9 IV Dengue and Yellow Fever 12 V Tsutsugamushi Disease and Other Rickettsioses 13 VI Other Arthropod-Borne Diseases 17 VII The Enteric Diseases (Except Helminthiasis) 18 VIH The Acute Respiratory Diseases and Tuberculosis 27 I IX The Acute Infectious Diseases 33 X Other Infectious Diseases 38 XI Helminthiases (Except Filariasis) 40 XII Animals of Medical Importance 46 Bibliography 56 Appendices Appendix A Population Data - Medical Per- sonnel and Facilities Accord- ing to Prefectures B Anopheline Mosquitoes C Checklist of the Culicine Mos- quitoes of Formosa D Poisonous Snakes E Checklist of the Muridae of Formosa F A list of Formosan Ticks FOREWORD The purpose of this manual is to present a condensed picture of the prevalence, distribution, and epidemiology of diseases of Naval importance in Formosa together with information on the distribution, habits, and identifi- cation of vectors and reservoir hosts. Because some of the important sources of material are not available in this country or were unavailable for various other reasons, some of the material is not as complete as would be desirable. This is particularly true for some of the acute infectious diseases and the venereal diseases. Emphasis has been placed on the epidemiology of those diseases which present a picture different from that which has been experienced elsewhere by Naval medical and H-V(S) officers. Hence, although the acute respiratory diseases are the most important cause of morbidity and mortality, more attention is devoted to the arthropod-borne diseases and helminthiases because the latter will present more novel situations to our personnel. An apparently disproportionate amount of space has been given to tsutsugamushi disease in view of the small number of cases reported annually. However, experience has already shown that this disease may become exceedingly important under combat conditions. Considering this and also the fact that its epidemiology, both on the main island of Formosa and in the Pescadores Islands, differs from the epidemiology of tsutsugamushi disease elsewhere, a more elaborate discussion was thought to be desirable. The area included in this manual is primarily the main island of For- mosa although material on the Pescadores Islands has been included when- ever available. Reference is made occasionally to the Loochoo (Ryukyu) Islands for comparative purposes. The principal sources of statistical information have been the official reports in the Statistical Yearbook of the Japanese Empire (in Japanese) and the Taiwan Sotokufu Tokeisho (in Japanese), the Statistical Reports of the Formosa Government. Other important sources of information have been the Taiwan Igakkai Zassi (Journal of the Formosan Medical Association); the entomological journals Kontyo.THe Insect World, and Tenthredo; Kitasato Archives of Experimental Medicine; Gunidan Zassi. the official publication of the Imperial Japanese Army Medical Corps; Transactions of the Natural History Society of Formosa; Kaigun Iji Hokoku Satsuyg Kaigunsho. the reports of the Medical Bureau of the Japanese Navy; and Dobutsogaku Zassi; as weH as other Japanese journals and monographs. The bibliography contains a list of the principal references used. Bureau of Medicine and Surgery Division of Preventive Medicine Section of Epidemiology June 10, 1944 CHAPTER I INTRODUCTION Formosa is a large continental island which is separated from the east coast of China by the Taiwan Strait, the width of which varies from ninety to two hundred miles. In the southern part of the Taiwan Strait lie the Pescadores GBOko) Islands, sixty-four in number. To the north and east of Formosa lies the Ryukyu (Loochoo) Archipelago which extends to the southeastern tip of Kyu- shu, the southernmost island of Japan proper. Latitudinally Formosa is bisected by the Tropic of Cancer. It is in the form of an elongated oval with northeast- southwest axis about 225 miles. The breadth varies from 60 to 80 miles. The area of Formosa is about 14,000 square miles. The island can be divided into three parts, the broad western slope with its alluvial plains, the mountains proper, and the narrow eastern slope terminating in a high and precipitous coast. In addition to the main island and the Pescadores (Boko) group, Formosa proper also includes fourteen small islands lying at various distances from the coast. Formosa presents a variety of climates, frigid, temperate, subtropical, and tropical depending on altitude and exposure. However, in general, the climate is tropical and is influenced by warm ocean currents. On the plain the temperature falls below 15°C. only in January. In Taihoku the average maximum temperature is 36.2°C. and the average minimum tempera- ture is 4.8°C. The absolute maximum is 38.6°C. and the absolute minimum is 0.2®C. In Taito the average maximum temperature is 35.40C. and the average minimum temperature is 10.4°C. The absolute maximum is 39.0°C. and the absolute minimum is 7.4°C. The rainfall of Formosa is high and well distributed throughout the year although the southern part is relatively dry in winter. The annual rainfall is 2,123 mm. in Taihoku, 1,785 mm. in TaitS, 1,517 mm. in Sinchiku, 1,774 mm. in Taichu, 1,730 mm. in Tainan, 1,607 mm. in Takao, 1,925 mm. in Karenko, 6,665 mm. in Kashoryo (near Kiirun) and 993 mm. in Bbko. The dry and rainy seasons in the north occur at precisely the opposite time of the year at which they occur in the southern part of the island, hi the north due to the seasonal northeast wind, the rainy season is fairly cold and lasts from October to March. The rainy season in the south (April to September) is characterized by frequent heavy tropical rains. The population of Formosa is predominately Formosan Chinese with the Japanese and aborigines constituting the minorities. This is illustrated by the following table; 1 TABLE I Population Groups in Formosa Year Formosan Chinese Japanese Aborigines 1922 3,614,207 187,953 83,164 1931 4,426,122 243,872 88,698 1938 5,392,806 308,814 156,017 The Chinese are mainly derived from Fukien and Kwangtung Provinces and are particularly predominant in the coastal plain. The aborigines are divided into subdued aborigines and wild aborigines. The latter constitute a serious prob- lem for the Japanese and are enclosed by an electrified guard-line of over 300 miles. For administrative purposes the island has been divided since 1920 into five prefectures and three districts. In the heavily populated western part of the island there are five prefectures: Taihoku, Shinchiku, Tainan, Takao, and Taichu. The eastern part, which is sparsely populated, consists of two districts, Taito and Karenko. The Boko Islands (Pescadores) comprise a third district. The area, population and population densities are given in the following table: TABLE II Area, Population and Population Density of Formosa Arranged by Prefecture and District Prefecture and District Area in square miles Popu- lation Number of people per square mile Total 13,886 4,932,433 355 Taihoku 1,762 998,103 566 Shinchiku 1,775 709,478 400 Taichu 2,850 1,096,925 385 Tainan 2,092 1,241,597 593 Takao 2,208 673,267 305 TaitS 1,361 62,685 46 Karenko 1,786 95,366 53 Boko 49 65,012 1,327 Since 1920, the health administration of Formosa has followed closely that of Japan. The Sanitary Bureau of the Government-General of Formosa is in charge of the health administration of the whole territory. In the 2 prefectures the health affairs are undertaken by the Sanitary Division of the Bureau of Police while in the districts by the police physicians. The Central Research Institute, the Research Bureau of Tropical Medicine and the Taihoku Medical College have done a great deal of research and investigation. Medical care is undertaken at the hospitals and clinics. The following table shows the number of hospitals, physicians, etc., in the years of 1932 and 1937. TABLE IE Medical Personnel and Facilities in Formosa Medical Personnel and Facilities 1932 1937 General practitioners 305 ♦ Other physicians 1,403 1,834 Dentists 263 402 Pharmacists 123 1-90 Midwives 1,524 1,744 Government Hospitals 14 15 Public Hospitals 18 18 Private Hospitals 164 221 Druggists 2,649 3,335 Pharmaceutical manufacturers 20 29 ♦Data not available The prefectural distribution of the hospitals, physicians, and other medical personnel in 1932 is shown in Appendix A. CHAPTER II MALARIA Malaria is one of the most important causes of morbidity 3nd mortality in Formosa. As a cause of death it takes an inferior rank only to tuberculosis, the acute respiratory infections, and the acute enteric diseases. In 1915 there were more than 13,000 deaths recorded as due to malaria. Since that time this number has been reduced considerably so that in 1932 only 3,335 malaria deaths were recorded. This is 3.4 percent of all deaths due to disease. In 1935 it was estimated that 85 percent of the malaria cases were from the eastern and western coasts and in the southern half of the island. The mountainous areas as well as such large cities as Taihoku, Taichu, and Tainan are virtuaHy free of malaria. According to the reports in the Statistical Yearbook of the Japanese Empire, malaria occurs in all of the prefectures and districts although the situation in the Boko (Pescadores Islands) is not clear. The available reports from recent years do not list cases of malaria from these islands and the only species of anopheline mosquito repotted by Morishita (1936) is the brackish water species, Anopheles indefinitus, which is not generally regarded as a malaria vector. Mittsunaga, Kasugawa, and Uchida (1916) listed in the reports of the Medical Bureau of the Japanese Navy Department 5,948 cases of malaria and 61 deaths due to malaria for the years 1908-1913 inclusively. The data from the Statistical Yearbook of the Japanese Empire also indicate that malaria occurs during every month of the year. Further emphasis concerning the importance of malaria in Formosa comes from the statistical studies of Nisimura (1931). The following table is taken from the data compiled by this author. TABLE IV Malaria Cases in Government and Public Hospitals Year Number of Malaria Cases Percent of all Admissions 1897 47,342 21.7 1902 31,039 22.8 1907 49,129 21.6 1912 45,975 22.2 1917 81,739 28.0 1922 73,569 16.9 1927 78,960 12.4 1930 65,481 10.3 ♦1932 83,932 ♦Added from Statistical Reports of Formosan Government. This figure includes outpatients. Nisimura (1931) cites the results of examinations of 2,271,679 persons for plasmodia at 145 localities in 1930. Of these 34,182 (1.5 percent) were found to be positive. This represents a considerable decrease from the results of the investigations of 1915-1925 when rates of two to three percent were observed. Although vivax-, malar iae-, and falciparum-malaria are all known to occur in Formosa, it is commonly stated that vivax infections are the most common. As in other areas malar iae infections are sporadic. Hatori (1925) examined 23,000 school children in Taihoku and found vivax, falciparum, and malar iae in the ratio of 72:68:10. Mitakayeshi (1927) in eastern Formosa, however, found that 68 percent of the cases were falciparum infections, 22 percent were vivax, and 7 percent malar iae; the remainder were mixed. Among 816 cases observed by Akashi and Yoshimura (1937) 54 percent were vivax in- fections, 42 percent were falciparum, and 1 percent were malar iae. Because the anopheline vectors are widely distributed and because large numbers of human reservoirs are present, malaria must be regarded as a most important disease from the standpoint of operations. THE MALARIA VECTORS According to the latest available paper by Morishita (1936) there are at least fourteen species and subspecies of anopheline mosquitoes in Formosa. Eight of these are known or suspected to be vectors of malaria. Information concern- ing the systematics and distribution of Formosan anophelines is drawn principally from the papers of Koidzumi (1926, 1927, 1927); Koidzumi and Morishita (1932); and Morishita (1932, 1932, 1936, 1936, 1936, 1936). Material on the feeding habits of the various species is derived largely from the studies of Morishita and Katakai (1933) whereas the information on natural and artificial infection is that derived from the studies of Anazawa (1926, 1926, 1928, 1931)* This section is devoted primarily to the available information concerning the relation of Formosan anophelines to the epidemiology of malaria and to such information as may be of value in planning and executing control measures. Ma- terial pertinent to nomenclature identification, taxonomy, and detailed distribution is assembled in Appendix B. 1. Anopheles hyrcanus sinensis. This subspecies is typically a swamp and rice field breeder although the larvae are also found in drainage ditches, puddles, lakes, burrows, drains, grassy pools, etc. Usually the larvae are found in open water although sometimes in shady places. It is generally a clean water species. It is commonly a fresh water form although it has been known to breed in brackish water in India. Anopheles hyrcanus sinensis is essentially a wild mosquito and breeds independently of the proximity of habitations. It is characteristically, although not necessarily, a mosquito of open country because of its close associa- tion with rice fields. It does not usually occur at higher altitudes because of the absence of rice fields. It feeds on both humans and animals not only at night but also sometimes during daytime. Using precipitin tests Morishita and Katakai (1933) found that only two percent of the females feed on human blood and that the principal hosts are water buffaloes and cattle. Adult females are frequently found in stables after having sucked blood. The role of sinensis in the transmission 5 of malaria varies considerably from area to area. Anazawa (1931) has found a natural infection index, 0.8 percent in Formosa. His experimental data show an experimental infection index of 60 percent with vivax, 17 percent with malariae and no infection with falciparum. Anopheles hyrcanus sinensis should be regarded as an important vector in Formosa. According to Koidzumi (1927) and Morishita (1936) it is the most common mosquito in Formosa. 2. Anopheles minimus. This species is especially a breeder of slowly running streams with grassy edges, edges of swamps, seepages from springs, burrow pits, and rice fields. The typical breeding water is fresh, clear, rela- tively cool, standing or flowing, sunlit or shaded. Larvae are not found in foul water, brackish water, or in rapid currents. In rice fields the larvae are gener- ally found only where there.is fresh cool water. In the Philippines minimus flavirostris is typically a brook breeder and it is possible that the same may be true in Formosa. Anopheles minimus is usually regarded as a species of the low and moderate altitudes. It is moderately anthropophilic in areas with live- stock and much more anthropophilic in areas where there are few livestock. Morishita and Katakai (1933) found that about 20 percent of the females obtain meals of human blood. In general Anopheles minimus is an important vector throughout its range. In Formosa Anazawa (1931) stated that 2.4 percent of the females were infected. Experimentally (1931) he was able to get infections of 65 percent with vivax, 12 percent with malar iae, and 64 percent with falciparum. Morishita (1936) states that it is found throughout the entire island and according to Koidzumi (1927) it is, next to sinensis, the most numerous species. 3. Anopheles maculatus. The breeding habitats of this mosquito are essen- tially streams and river beds; it has been found breeding much less frequently in pools, lake margins, rice fields, drains, and occasionally in artificial receptacles. The breeding waters are usually clear, we 11-oxygenated, and exposed to sunlight. Frequently malaria has become endemic in upland areas as the result of removing the shade from the streams thereby making breeding habitats for Anopheles macu- latus. This species may occur at altitudes as high as 3,000 feet, although it may - not be found at these altitudes in Formosa. Little has been published concerning its breeding habits in Formosa although in Malaya and the Netherlands Indies it is known to be strongly anthropophilic. In Formosa Anazawa (1931) has observed it to be anthropophilic. It is more frequently captured in traps than in dwellings. Natural infections of 0.4 percent have been recorded in Formosa by Anazawa (1931). The same author (1931) obtained experimental infections of 63 percent with vivax, 32 percent with malar iae, and 48 percent with falciparum in Anopheles maculatus. According to Morishita (1936) it occurs throughout the island. Koidzumi (1927) states that it is most numerous in the foothills and in the mountains. It is the third most common species although it is rare in the northern part of the island. It should be regarded as a vector in Formosa, especially at higher altitudes. 4. Anopheles maculipalpis splendidus. This form is frequently regarded as a distinct species, Anopheles splendidus. Its larvae usually occur in small pools along mountain streams and irrigation ditches. Also they have been found in drain- age water, slowly flowing streams with sandy or stony bottoms, and in ponds with aquatic vegetation. This mosquito occurs either on the plains or in the mountains In Formosa Anazawa (1931) has found that the females remain in the stables or dwellings after obtaining their blood meal. He found a natural infection rate of 2.3 percent (second only to minimus) and experimental infection of 57 percent with vivax, 6 36 percent with malariae, and 27 percent with falciparum. Both animals and man are attacked by females. Morishita (1936) states that it is widespread over the entire island. Although Koidzumi (1927) regarded it as a rare form, its widespread range and the observed rate of natural infection demand that it be provisionally recognized as an important vector in spite of the fact that it is not so regarded elsewhere. 5. Anopheles ludlowii. This is a fresh water species known only from the Philippines, Ceram, Formosa, and possibly Hainan. In Formosa it was known for many years as Anopheles hatorii. Anopheles ludlowii should not be confused with the so-called 'Tudlowi” (sundaicus) of many authors which is the important malaria vector of Malaya and the Malay Archipelago. In the Philippines, Anopheles ludlowii larvae are found in the clear water of shaded or exposed streams or rivers, sometimes in pools. The larvae seem to pre- fer the wider parts of the streams where the water is stagnant. Anopheles ludlowii is not regarded as a vector of malaria in the Philippines where all dissections have been negative. Anazawa (1931), however, has reported a rate of natural infection of 0.4 percent. Experimentally (1931) infections of 61 percent with vivax, 15 percent with malar iae, and 68 percent with falciparum were obtained. Morishita and Katakai (1933) have shown that it has a definite preference for the blood of cattle and water buffalo and rarely, if ever, attacks man. It has been recorded from the central, southern, and eastern parts of Formosa including the eastern part of Taihoku Prefecture. According to Koidzumi (1927) it is common in the central and southern parts (next to minimus and maculatus) and along the east coast and rare in the northern part. It is probable that Anopheles ludlowii will not prove to be a vector of importance in Formosa. 6. Anopheles jeyporiensis candidibnsis. Little has been published con- cerning the breeding habits of this subspecies. Apparently larvae have been found in slowly flowing streams and grassy irrigation ditches. In Hong Kong the females of this species are known to be domestic in their habits; more than 50 percent were found with human blood. In many areas in southern China it is regarded as second in importance only to Anopheles minimus as a vector. According to Morishita (1936) candidiensis has been found only in a few localities in Taichu-Shu. Because of this limited distribution it does not appear that this species will be found to be an important vector of malaria in Formosa. 7. Anopheles annularis. The larvae of this species are usually found in clean, weed-grown, stagnant, quiet water, particularly, margins of lakes, tanks, moats, dead rivers, swamps, rice fields, ponds, pools, in rivers when there is vegetation, etc. In Indo-China they have been found in tree holes and bamboo stumps. The females were found by Anazawa (1931) in Formosa to be more zoophilic than anthropophilic; biting occurs daytimes as weH as at night. Natural infections of 0.2 percent have been found in Formosa by Anazawa (1931). His data on artificial infections show rates of 56 percent for vivax, 20 percent for malar iae, and 89 percent for falciparum. Morishita’s data (1936) show that annularis is found throughout Formosa although it is rare in the northern part of the island. Because of its low natural infection it is probably unimportant as a vector although it should not be overlooked as a possibility. 7 8. Anopheles tessellatus. The larvae of this species occur most frequent- ly in small pools, irrigation ditches and drains, and swamps. Little is known of the habits of the adults. In the Netherlands Indies and Indo-China they are thought to attack cattle and buffalo in preference to other sources of blood. These ob- servations have been confirmed by Morishita and Katakai (1936) although Anazawa (1931) thought that they are more anthropophilic. The females tend to remain in the dwellings and stables after feeding. Anazawa (1931) observed a natural infection rate in Formosa of 1.9 percent somewhat higher than obser- vations elsewhere. Because of this and its widespread distribution throughout the island it should be regarded as a vector of potential importance. Koidzumi' (1927) says that it occurs throughout the island in the plains and foothills. Frequently it is more numerous around the cities and villages. 8 CHAPTER III FILAR IASIS Reports are not in precise agreement as to the status of filariasis in Formosa. Yokogawa and Morishita (1931-1933), Japanese parasitologists who have made extensive studies in Formosa, stated that although this disease is common in the Loochoo Islands, southern Japan, China, and the Philippine Is- lands, it is surprisingly uncommon in Formosa. However, they do give records of several cases. Later Yokogawa et al (1939) in discussing their investiga- tions in the Boko Islands state that Formosa “was believed to be free of filariasis”. Another report of undetermined origin and authenticity states that filariasis does occur in Formosa to a limited extent and is more common in the southern part of the island. Yokogawa and Morishita (1931-1933) also point ed out that many of the cases reported from Formosa have been allochthonous although they seem to imply in this treatise that there have also been autoch- thonous cases. These authors are unable to offer an explanation for the low incidence of filariasis in Formosa in view of the surrounding endemic regions pointing out that Culex quinquefasciatus. which has been shown in Formosa to develop infective larvae, is such a common mosquito. The filariasis of For- mosa is caused by Wuchereria bancrofti. No information could be found con- cerning the periodicity of the microfilariae, although the filariasis of the Loochoo Islands and the Boko Islands has been observed to be nocturnal. In the Loochoo Islands filariasis is highly endemic. Ohama (1939) re- ported microfilaria indices of 20 percent and 12 percent among the school children of Kabira and Taketomi respectively. The same author (1941) found a microfilaria index of 24 percent among the school children in Slrara. Yosino and Nakasato (1941) have reported indices as high as 29 percent in the Loochoo Islands. The story of filariasis in the Boko Islands is very interesting and may lend some light to the situation on the main island of Formosa. Tanaka (1937) reported that prior to 1937 only a single case had been reported but that one would expect the disease to be there because of the geographical position of the islands as well as the abundance of Culex quinquefasciatus. In an examina- tion of 229 individuals made by this investigator 43 percent were found to have “signs” of filariasis and 16 percent had microfilaria in the night blood. He concluded the islands to be highly endemic. The same author (1938) reported eight cases from the Boko Naval Station, one of which showed no periodicity. The others were of the nocturnal type. During the summer a large group of investigators under the direction of Yokogawa (1939) made a filariasis survey of the B5ko Islands. The results are as follows: 9 TABLE V Microfilaria survey in the Boko Islands Island Village Number Examined Type Percent Positive Hakusya Gado 340 Adults 7.35 Hakusya Gado 117 School Children 0.85 Boko Mako 1,235 School Children 9.55 Boko Kosei 867 School Children 11.22 Gyoo Gdkaito 40 School Children 1.25 In view of the fact that before 1936 filariasis was assumed not to occur in the Boko Islands only to be subsequently found as prevalent, the possi- bility arises that a similar condition could exist on the main island. Certainly this possibility is sufficiently plausible to warrant some attention at the time of occupation. VECTORS As in many areas the question of the intermediate hosts of Wuchereria bancrofti in Formosa is not clear and although there is considerable evidence to implicate Culex quinquefasciatus it should by no means be assumed that this species is necessarily the important vector. Actually, the reported low inci- dence of filariasis and the abundance of Culex quinquefasciatus, make it diffi- cult to assume that the picture is a simple one. The following notes on the vec- tors (essential intermediate hosts) of filariasis have been taken from various sources and should be regarded only as suggestions as to species which may serve as vectors. 1. Culex quinquefasciatus. This species is regarded as an important vector in Japan by Esaki (1932), and as a vector in Formosa by Yokogawa and Morishita (1931, 1933), and Abe (1937). It is also thought to be the vector in the Loochoo Islands and Yokogawa et al (1939) regarded it as the vector in the B5ko Islands-. Abe’s conclusions are based on experiments in which he was able to demonstrate the development of infective larvae in the females. Culex quinquefasciatus is a cosmotropical and subtropical species and is ubiquitous in its breeding habits. Larvae are found in all sorts o* accumula- tions of water such as tanks, wells, pits, water barrels, toilets, fountains, cisterns, ponds, canals, ditches, and other fresh water habitats. It has been reported as common on the main island of Formosa as well as in the Boko Islands and the Loochoo Archipelago. 2. Anopheles hyrcanus sinensis. This subspecies has been reported as a vector in China and elsewhere in the orient. Esaki (1932) lists it as possibly a vector in Japan and Formosa although Midzuki and Mihara (1927) regarded it as an important vector. The habits and distribution of this species are dis- cussed in the chapter on malaria. 3. Culex vishnui. This species has been found with infective larvae on Kabaena near Celebes by Brug (1938). However, according to Esaki (1932), only partial development of the larvae has been observed in Japan and Formosa. Culex vishnui has been reported from Formosa. A Culex pipiens. This species is regarded as a vector in southern Japan by Esaki (1932). However, no records could be found of its occurrence in Formosa. 5. Culex whitmorei. Esaki (1932) includes this species in his list of vectors of Wuchereria bancrofti although the authority for the statement is not given. Brug (1938) was able to get experimental infections and the deve- Ippment of infective larvae with this species on Kabaena Island near Celebes. Culex whitmorei is reported from Formosa in Esaki’s compilation although there is no information concerning its abundance and distribution. 6. Culex tritaeniorhynchus. Esaki (1932) also lists this species from Formosa and designates it as “possibly an intermediate host” of Wuchereria bancrofti. Brug’s (1938) experiments lead him to describe it as a possible experimental vector. 7. Culex tipuliformis. This species has been reported from Japan, South China, and India and is listed by Esaki (1932) as a vector of filariasis. It is possible that this species may ultimately be found on Formosa. 8. Mansonia uniformis. This widespread species has been recorded in Formosa. Although Brug does not regard any of the Mansonia species as vec- tor of Wuchereria bancrofti in the Netherlands, Esaki (1932) lists it as a possible vector in the Japanese Empire. 9. Aedes togoi. Yamada (1921) has apparently demonstrated that this mosquito can be an intermediate host of Wuchereria bancrofti, and it is in- cluded in Esaki’s list of vectors. Data are not available concerning its abun- dance in Formosa although there are records from the island. Aedes togoi is anthropophilic and attacks during the day as well as night by artificial light. Esaki (1932) lists the following Formosan mosquitoes in which partial development of the larvae has been observed: Culex bitaeniorhynchus karatsuen sis, Culex sitiens, Culex vishnui, and Armigeres obturbans. 11 CHAPTER IV DENGUE AND YELLOW FEVER Epidemics aS well as sporadic cases of dengue occur in Formosa, as well as in the Pescadores and Loochoo (Ryukyu) Islands. According to Matsu- moto (1935) the epidemics in Formosa occur in the southern part of the island. The disease seems to be particularly prevalent in the latter group where Miyao (1931) and Kitano (1931) reported an epidemic involving more than 35,000 cases occurred in 1931. An epidemic in the Pescadores in 1922 as described by Goto (1923) involved more than one-third of the entire population. The 1931 epidemic also swept through parts of Formosa proper and has been described by Suenaga (1931) and Akasi (1932). It was associated with high temperature , rainfall, and humidity. Miyao (1931) and Koidzumi (1918) state that both Aedes albopictus and Aedes aegypti occur in Formosa and the Loochoo Islands. Both axe regarded here, as elsewhere, as vectors of dengue. Aedes aegypti (=Stegomyia fasciata) is cosmopolitan in its distribution between 40UN. and 40°S. latitude. More is known of its habits and biology than of any mosquito. Its habits are apparently no different in Formosa than elsewhere. Larvae can be found in all types of artificial accumulations of water even in minute volumes. Typical breeding places are rain barrels, tanks, cisterns, tin cans, urns, as well as water accumulated on leaves and in plant axils. It is almost exclusively a house mosquito and is rarely found more than 1500 feet from habitations of some type or other. It is strongly anthropophilic. The younger adults are apparently daytime fliers until a meal of blood is secured and is thereafter nocturnal. It is said to prefer to attack whites in preference to dark-skinned people. There are sufficient records to allow the conclusion that this species is widespread in Formosa. According to Esaki (1932) it is also common in the Pescadores Islands. Aedes albopictus. also regarded as a vector in Formosa, has not been reported as frequently as aegypti. However, Esaki (1932) describes it as a common mosquito in Formosa. It breeds near dwellings, frequently in habitats similar to those of Aedes aegypti. Larvae are found in water tanks, tin cans, cisterns, plant axils, rain barrels, etc., and rarely in ponds, ditches, and mud puddles. It is also strongly anthropophilic and its bite is more irritating than that of aegypti. YELLOW FEVER No authentic reports of yellow fever have been found from Formosa or any of the adjoining areas. Aedes aegypti known to be a vector elsewhere is common in Formosa and the introduction of yellow fever would doubtlessly result in its rapid spread through the native population. 12 CHAPTER V TSUTSUGAMUSHI DISEASE AND OTHER RICKETTSIOSES Tsutsugamushi disease has been known in Formosa since 1908. Hatori (1919) has described the early history of the disease in Formosa and outlined accurately its epidemiology and distribution. Kawamura and Yamaguchi (1921) showed that it was identical or at least very similar to the tsutsugamushi disease of Japan. The best general account of tsutsugamushi disease in Formosa is that of Morishita (1942, 1939, 1939). In contrast to the situation in Japan where it is confined to the flood plains of certain rivers, tsutsugamushi disease has a much more general occurrence in Formosa. It occurs not only in the plains but also in the mountainous regions. It is endemic in all five prefectures and the two districts of the main island. The endemic areas are poorly defined. The physical features of the endemic areas vary greatly including riversides, cultivated fields, foothills, jungles both in the plain and in the mountains as high as 6,500 feet. According to Morishita (1942) the majority of the cases come from the plains and foothill districts of the Karenko and TaitO districts in the east, although it occurs also in the mountainous regions of Tainan, Taichu, and Shinchiku prefectures in the middle of the islands and in the plains and foothill regions of Takao prefecture in the south. The incidence of tsutsugamushi disease in Formosa is low; it is a relatively .unimportant cause of morbidity and mortality. The statistics in the following table are from Morishita (1942): TABLE VI Annual Number of Cases of Tsutsugamushi on the Main Island Year Cases Deaths Case Fatality in Percent 1923 67 12 17.9 1924 88 8 9.9 1925 81 17 21.0 1926 72 6 8.3 1927 95 9 9.5 1928 72 7 9.7 1929 84 11 13.1 1930 74 6 8.1 1931 82 5 6.1 1932 163 13 8.0 1933 49 5 10.2 1934 35 4 11.4 1935 18 0 0. 1936 26 2 7.7 1937 16 4 25.0 1938 22 6 27.5 13 Despite its low incidence tsutsugamushi disease should be regarded as a disease of great potential importance to Naval personnel who are required to enter the habitats frequented by the larvae of Trombicula akamushi, the vector. In Formosa the disease occurs throughout the year, the seasonal peak comes between July and October as shown in the following table. TABLE VII Seasonal Occurrence of Tsutsugamushi Disease from 1933-1938 Month Cases Percent January 19 11.4 February 2 1.2 March 1 0.6 April 4 2.4 May 14 8.4 June 20 12.0 July 25 15.1 August 16 9.6 September 14 8.4 October 23 13.9 November 18 10.8 December 10 6.0 In general about five times as many cases occur among men as among women. More than fifty percent of the cases are in the 21 to 35 age groups. Both of these observations can probably be explained on the basis of greater probability of the exposure of males of these age groups to the habitats of the mite larvae. Case fatality increases, according to Morishita, from 3.3 percent in the 1-5 year age group to 45 percent in cases over 45 years of age. It is interesting to note that the case fatality among the Japanese is 10.3 percent, 20.4 percent among the Formosan Chinese, and nil among the aborigines. THE VECTOR The only known vector of tsutsugamushi disease in Formosa is the hexapod larva (chigger) of Trombicula akamushi (Brumpt), also the vector in Japan. The chigger feeds once only during its lifetime and the rickettsiae are passed from female to offspring via the ova. The eggs of Trombicula akamushi are laid singly in the soil. The orange- red hexapod larvae (chiggers)which emerge from the eggs vary in length from 0.30 to 0.40 mm. These larvae are very active and run about on the ground litter and to a certain extent on the lower vegetation. These larvae are known 14 to attack a considerable variety of warm blooded vertebrates. Digestive fluids are injected into the tissue of the host and the resulting semi-digested material is withdrawn by the mite larvae. After becoming fully engorged the larvae drop to the ground and become quiescent. During the ensuing period the appendages and certain other organs undergo histolysis. When the appendages reform they lie next to the body under the larvae skin and have no setae or armature of any kind. This stage is known as the nymphochrysalis. From the nymphochrysalis emerges the active octopod nymph which is similar to the adult although smaller. This numph remains in the soil and feeds on the juices of plants, particularly those of the roots. The nymphs evolve into the adults which also live in the soil. The sexes are externally similar except for slight differences in the genital region. In the temperate regions there is a single generation per year. Most of the summer is passed in the larval stage and the winter in the adult stage. In Formosa, however, it is probable that there is more than one generation per year In Formosa Trombicula akamushi larvae has been found parasitizing the common Indian rat, Rattus rattus rule see ns; the Norway rat, Rattus norvegicus, as well as Rattus losea, Rattus coxinga, Apodemus agrarius, Mus musculus, as well as dogs, cats, calves, oxen and buffalo. They have also been found on two insectivores, Suncus myosurus and Crocidura tanakae as well as on quail, phea- sants, goatsuckers, kingfishers, cuckals, and the domestic fowl. In the endemic areas Morishita (1942) has noted Rattus losea and Apodemus agrarius to be common and has suspected them as being reservoir hosts of the Rickettsia tsutsugamushi. He was able to isolate a strain of Rickettsia tsu- tsugamushi from Rattus losea. Hayashi (1926) has pointed out that birds may be of epidemiological importance not only as hosts of the mites but possibly also as reservoir hosts of the rickettsiae. TSUTSUGAMUSHI DISEASE in the Boko Islands. (Pescadores) Because of the mild nature of the disease in the Boko Islands, it was not detected there until 1931. The best accounts of the disease as it occurs on these islands are those of Kawamura and Yamamiya (1939) and Morishita (1942). The epidemiology of tsutsugamushi disease in the B5ko Islands is strikingly different from that of the main island. The dwellings are directly surrounded by endemic areas so that all individuals are exposed to infection without regard to age, sex, or occupation. The case fatality is low (about 5 percent). This is probably due to the milder strain of Rickettsia tsutsugamushi and further to the fact that the majority of the cases (seventy percent) occur in children of fifteen years or less, thirty-eight percent occur in children of less than five years. The disease is seasonal in Boko with all of the cases thus far recorded having occurred from April to November. The majority of the cases occur in June and July. The monsoon season is from October to March. The following statistics were compiled by Morishita (1942); 15 TABLE Vin Annual Number of Cases in the Boko Islands Year Cases Deaths Case Fata- lity Percent 1932 17 1 5.9 1933 12 0 0. 1934 20 1 5.0 1935 55 0 0. 1936 64 5 7.8 1937 80 2 2.5 1938 33 7 21.2 Total 284 16 5.6 The vector of tsutsugamushi disease in the Pescadores is also the larvae of Trombicula akamushi. The larvae apparently develop in the ground within the coral walls which surround the dwellings and gardens of the natives. Rattus rattus rufescens. a semi-domestic form, has been found to be heavily infested with the mite larvae and rickettsiae have been found in its tissues. The other rodents are Mus muscuius, the house mouse; and Rattus norvegicus. There are no wild rodents. Morishita (1942) is inclined to feel that rufescens is important in the epidemiology of tsutsugamushi disease in the Boko Islands. OTHER RICKETTSIOSES The official reports of the Formosan government from 1913 to 1937 contain a single record of typhus, one case reported in 1914. Asano (1940) says that it was first reported from Formosa in 1909-1910. He includes Formosa in his list of endemic localities. It appears that his reference is to endemic typhus. Several species of rats known to be potential reser- voirs of endemic typhus are known to occur in Formosa. (See chapter on Animals of Medical Importance.) According to Sugimoto, Xenopsylla cheopis, the rat-to-man vector of endemic typhus, occurs in Formosa (Taihoku) although Esaki (1932) indicates that it is confined to the port cities. Omori (1936) also has reported it from Formosa. There is also the constant possi- bility of the introduction of endemic typhus from the endemic areas in China, Japan proper, and other parts of the orient. According to Esaki (1932) the body louse, Pediculus humanus corporis, the vector of epidemic typhus, also occurs in Formosa. This raises the possibility of the introduction of epidemic typhus. Ohshiro (1931) has reported five cases of a so-called “indistinct fever” in Karenko and on the Boko Islands. Because of the strong positive Weil- Felix reaction (type not specified) the author was inclined to regard the disease as a “mild form of exanthematous typhus”. Whether these cases were actually a mild type of tsutsugamushi disease, endemic typhus or some other disease it is not possible to ascertain from the description. 16 CHAPTER VI OTHER ARTHROPOD-BORNE DISEASES Plague. The last officially reported cases of plague in Formosa were recorded in 1917. The following table gives the official case records for the period 1913-1918 inclusive: TABLE DC Plague in Formosa 1913-1918 Year Cases Deaths 1913 136 125 1914 567 488 1915 74 66 1916 5 4 1917 7 7 1918 0 0 Prior to 1913 the disease was more prevalent. For example, in 1906, %271 cases and 2,613 deaths were recorded. Although no cases of plague have been officially reported from 1918 through 1938, the last year for which data are available, there is the possi- bility that it has been reintroduced since that time or that it will be reintroduced subsequently under wartime conditions. The necessary murine reservoirs are present as well as the tropical rat flea, Xenopsylla cheopis. which is the rat- to-man vector. Tick-borne relapsing fever. The official reports of the Formosan govern- ment contain no records of cases of this disease nor could any be found in the literature. Furthermore, no records of Ornithodorus species have been found in the literature. Louse-borne relapsing fever. The official reports of the Government of Formosa contain no records of this disease. Furthermore no records of cases could be found in the literature. The body louse, Pediculus humanus cor poms, which is the vector, is known to occur in Formosa. Leishmaniasis. Matsunaga (1935) points out that although leishmaniasis (kala-azar) occurs in China and Manchukuo there are no authentic records of it in the Japanese Empire including Formosa. Tick-borne typhus. No records of this disease in Formosa have been found. Chaga’s disease. Loiasis. and Onchocerciasis also appear to be unreported in Formosa. CHAPTER VH THE ENTERIC DISEASES (Except Helminthiasis) That the enteric diseases have been for sometime an important cause of death In Formosa is evidenced by the following figures taken from Taiwan Sotokufu Tokeisho (Statistical Report of the Formosa Government) for 1934. TABLE X Year Total Population of Formosa Typhoid Deaths from Para- typhoid Dysentery Ekiri Diarrhoea Enteritis 1932 4,932,433 206 Rate per 1,000 0.04 9 Rate per 1,000 0.002 45 Rate per 1,000 0.009 30 16,394 Rate per. Rate per 1,000 1,000 0.006 3.32 The great majority of the deaths from these diseases have, however, been in infants. Thus of the 16,394 deaths from diarrhoea and enteritis in 1932, 11,490 occurred in infants under 2 and 4,904 occurred in persons 2 years of age or older. Furthermore most of these deaths have been chargeable not to the specific infections (typhoid, paratyphoid, bacillary dysentery, and amoebic dysentery) but to the non-specific infectious ekiri of infants and diarrhoea and enteritis. DIARRHOEA AND ENTERITIS The deaths from diarrhoea and enteritis appear to follow a seasonal trend with the peak being reached sometime during May, June or July. Thus the Statistical Report of the Formosa Government, 1934, records that the deaths each month in 1932 from diarrhoea and enteritis were as follows: TABLE XI Jan. Feb. Mar. Apr. May June J^y Aug. Sept. Oct. Nov. Dec. 758 625 657 1147 2798 2358 2131 1636 1257 1117 1082 828 The distribution of the deaths from diarrhoea and enteritis through the eight (8) different prefectures was as follows in 1932 (Statistical Report of the Formosa Government, 1934): 18 TABLE XII Taihoku Shin- chiku Taichu Tainan Takao Taito Karenko Boko Deaths 2,062 Rate per 1,076 3,700 6,262 2,606 190 192 298 1,000 2.09 1.52 3.38 5.04 3.87 3.03 2.01 4.58 No figures are available as to the mortality from diarrhoea and enteri- tis in Formosa since 1932. TYPHOID AND PARATYPHOID FEVERS Typhoid fever and paratyphoid fever have not been diseases of first importance in Formosa during the last 11 years (1928-1938 inclusive) for which figures are available (see Table). No evidence, however, of a decreas- ing trend either in the incidence of or mortality from these diseases is discern ibie even if figures are consulted as far back as 1913. TABLE XIH Reported cases and deaths due to typhoid and paratyphoid fever in Formosa* Year Total Population Typhoid Fever Death rate per Cases Deaths 1,000 Paratyphoid Fever Death rate per Cases Deaths 1,000 1928 4,438,084 1,643 297 0.07 222 14 0.003 1929 4,548,750 1,454 315 0.07 149 27 0.006 1930 4,679,066 1,719 323 0.07 141 16 0.003 1931 4,803,976 1,100 243 0.05 79 8 0.002 1932 4,929,962 1,074 223 0.05 107 26 0.005 1933 5,060,507 1,139 246 0.05 32 8 0.002 1934 5,194,980 1,162 301 0.06 38 8 0.002 1935 5,315,642 1,450 328 0.06 55 7 0.001 1936 5,451,863 1,822 432 0.08 48 5 0.001 1937 5,609,042 1,475 349 0.06 45 15 0.003 1938 5,746,959 3,617 0 0. 93 0 0. ♦From the Statistical Yearbook of the Japanese Empire. Among the Japanese in Formosa it is apparently those who have been in residence less than 5 years who show the highest rate of incidence for typhoid. 19 TABLE XIV Number of Cases of Typhoid and Period of Residence in Formosa* Number of Period Number Percent of cases per of Popula- of total number 1,000 popu- Residence tion Cases of patients lation Less than 6 months II . 29.40 6 mos. to 1 year 1 year to 2 years 67 18.67 2 years to 3 years 47 10.09 3 years to 4 years 41 9.00 4 years to 5 years 30 6.44 Less than 5 years 60,265 342 5.7 5 to 10 years 26,440 87 3.3 10 years to 15 years 11,932 23 1.9 15 years to 20 years 11,802 13 1.1 ♦Maruyama Y. 1920. Tokyoer Medizinische Wochenschrift, Tokyo, No. 2163:297-300. Some evidence as to the seasonal prevalence is provided in the following figures: TABLE XV Deaths from Typhoid and Paratyphoid Fever, Formosa, 1932* Type Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Typhoid Para- 13 8 6 3 8 16 20 23 39 29 21 20 typhoid Total disease 1 2 .1 2 1 1 1 deaths 8113 6680 7728 7322 9832 9509 10021 9157 7612 7634 7590 7927 ♦Taiwan Sotokufu Tokeisho (Statistical Report of the Formosa Government, 1934) 20 TABLE XVI Seasonal Distribution of 724 Cases of Typhoid and Paratyphoid Ad- mitted to Child Dept. Taihoku Hospital, 1917 to 1928* Type Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Total Typhoid 38 29 25 28 59 81 72 62 53 38 39 47 571 Para- typhoid 6 3 8 6 13 35 24 17 9 6 20 6 153 Total 44 32 Percent 6.07 4.41 33 4.55 34 4.69 72 116 96 79 62 44 59 9.9416.0213.2510.918.56 6.07 8.14 53 7.32 724 ♦Chin, Kyu-Sui Feb., 1929 Taiwan Igakkai Zassi (Jour. Med. Assoc. Formosa), Taihoku, No. 287:175-206. TABLE XVII The distribution of the typhoid and paratyphoid deaths among the 8 prefectures of Formosa in 1932 was as follows: Deaths Talho- ku Shin- chiku Taichu Tainan Takao Taito Karenko Boko Typhoid Para- 126 5 15 35 12 3 9 1 typhoid 6 Death rate per 1,000 2 1 Typhoid Para- 0.13 0.007 0.01 0.03 0.02 0.05 0.09 0.02 typhoid 0.006 - - 0.002 0.001 - - Taiwan Sotokufu Tokeisho (Statistical Report of the Formosa Government, 1934) The following information is available on the types of B. typhosus isolated from cases of typhoid fever: T. Mori (in the Taiwan Igakkai Zassi (Journal of Med. Assoc., Formosa, 37(7): 1112-1117))reported that he had isolated 99 strains of B. typhosus from cases of typhoid fever in the Takao Hospital during 1936-37. It was found that 57 strains belonged to Type I, 36 to Type V, 3 to Type VI, and one each to Type H, HI and XI. These types are according to Shimojo and Soda’s classification which is as follows: 21 TABLE XVIII Cultures I II III IV V VI VII VIII DC X XI XII Xylose + + + + m% + + Teruchi- agar + + - - + + - - - - - - Gelatin + - + - + - + - + - + - Witte-agar + + + + + + + + - - - - Endo-agar + + + + + + + + + + + Kazuo Kubota (1940) reported on 162 hospitalized cases of typhoid fever with the following conclusions: (1) The mortality was 28.40 + 3.53 percent. (2) The mortality was 18.35 + 6.90 percent greater in the Formosan Chinese than among the Japanese. (3) The average time of hospitalization was 47.3 days for those who recovered and 19.1 days for the fatal cases. (4) Using Shimojo and Soda’s classification. 61 percent of cases were Type I 21 percent of cases were Type V 15 percent of cases were Type VI 1 percent of cases were Type U 1 percent of cases were Type III 1 percent of cases were Type XII DYSENTERY The incidence of dysentery and the mortality from the disease has been rather slight in Formosa since 1928 (see Table XIX). 22 TABLE XIX Reported cases and deaths due to dysentery in Formosa* Year Population Cases Rate per 1,000 Number of deaths Death rate per 1,000 1928 4,438,084 129 0.03 13 0.003 1929 4,548,750 202 0.04 31 0.007 1930 4,679,066 248 0.05 16 0.003 1931 4,803,976 245 0.05 34 0.007 1932 4,929,962 332 0.07 32 0.006 1933 5,060,507 260 0.05 34 0.007 1934 5,194,980 218 0.04 36 0.007 1935 5,315,642 255 0.05 47 0.009 1938 5,451,863 236 0.04 42 0.008 1937 5,609,042 302 0.05 49 0.009 1938 5,746,959 471 0.08 - 0. ♦From the Statistical Yearbook of the Japanese Empire. As far as can be determined from the limited statistics available it would appear: (1) that the season of greatest incidence of dysentery is June, July and August; (2) that the prefecture of Tainan usually reports the greatest number of cases; (3) that the highest death rate from dysentery is in the prefecture of Taito. Year 1932 Taihoku Shinchiku Taichu Tainan Takao Taito Karenko Boko Deaths from dysentery 11 1 27 2 3 1 Death rate per 1,000 0.01 0.001 0.02 0.003 0.05 0.01 TABLE XX (Statistical Report of the Formosa Government, 1934) As to the types of Shigella isolated from cases of bacillary dysentery only the following data are available; Uzuhiko Kurimoto and Taizo (1940) classified 61 strains of dysentery bacilli, which were isolated from patients in Taihoku in 1939, after tne classi- fication by Futaki: Types No. of strains Shiga-Kruse type 1 Komagome B type 13 Kawase type 1 (mannite-non-fermenter) Nakamura type 11 Ohara type 4 Serologically not identical with ,12 (mannite-non-fermenter) any type 19 (mannite-fermenter) 23 AMOEBIASES AND OTHER INTESTINAL PROTOZOAN IN- FECTIONS It is not possible to indicate the extent of morbidity due to amoebic dysentery because the type of dysentery is not specified in reporting communi- cable diseases. The prevalence of amebiasis as well as other intestinal protozoan infections is indicated to a certain degree by the results of stool examinations as recorded in the table at the end of this Chapter. Infections with Endamoeba histolytica appear to occur in rates of one to 25 percent varying according to locality and the type of people examined. Considerable attention has been given to giardiasis which has been found to be prevalent in some areas, especially among children. Balantidium coli has been reported in- frequently in humans although it is common in swine (60 percent in southern Formosa). CHOLERA Large epidemics of cholera were at one time known to ravage the island of Formosa. The last large epidemic was that of 1919-20 when 6,507 cases and 4,364 deaths were officially reported. Since that time sporadic cases have appeared in small numbers, particularly in the seaport cities. The following table is a compilation of cholera statistics of the Govern- ment of Formosa: TABLE XXI Cholera in Formosa Year Cases Deaths Year Cases Deaths 1913 1926 16 11 1914 _ _ 1927 _ 1915 _ 1928 _ 1916 34 16 1929 _ _ 1917 2 1 1930 _ — 1918 1 1 1931 1 1 1919 3,83 6 2,693 1932 18 6 1920 2,67 1 1,671 1933 _ 1921 1 _ 1934 _ — 1922 _ • 1935 » _ 1923 - - 1936 - _ 1924 1925 3 3 1937 — Because of the proximity of Formosa to the Chinese mainland, there is the constant danger of the introduction of cholera especially by the smaller native craft. This danger will doubtlessly be enhanced by wartime conditions when maintenance of inspection is difficult. SANITATION IN RELATION TO ENTERIC DISEASES Though water purification plants provide water of sanitary quality in the larger cities, the majority of Formosa’s rural inhabitants apparently drink untreated well or stream water. The sanitary quality of the well water apparently varies considerably but is superior to that of the stream water which suffers general contamination as the result of the unsanitary methods in general use for disposing of human fecal material. In rural areas sanitary privies or bored-hole latrines are still not in universal use and in the larger towns and villages the night soil from each house is col- lected into large tanks, is allowed to putrify and is then spread over the land as fertilizer. The failure to provide sanitary disposal of fecal material coupled with the presence of pigsties serves to make the fly problem a serious one. The chief species of flies are discussed in Chapter XII. 25 locality Ntonher examined Description Endamoeha histolytica & « 0 E -H CB f—4 xi 0 cl 0 w Endolimax nan a i •H •H «5 rH & 0) 0 0 8> S -4-> is & 9) n O *H S 1—4 m -h -p cl eo 0) u •H «H (S «J -H •H r—4 nd fe I •H H c!> •H xi *ri P C t-4 flj 1-4 i-4 O « O m Trichomonas Reference Per- cent Per- cent Per- cent Per- cent Per- cent Per- cent Per- cent Per- cent Hozan Japanese (S. Formosa) UO marines 0. 12.5 25.0 10.0 - 5.0 - - Kan (19JU) Hozan (S. Formosa) 156* schoolchildren 18.b 39.7 1^.1 23.7 - 30.1 - - Kan (193*0 North Formosa 616 lb.7 ll.U 16.7 1.5 - 6.2 • 2.8 Kawai et al (1936) Taihoku 259 medical students 8.5 8.5 8.1 2.0 - U.6 - - Morioka et al (1936) Tainan 1+29 prisoners 18.0 6.3 5.6 - 0.7 9.0 1.0 0.7 Namikawa (1936) Taihoku 971 Japanese schoolchildren 1.2 0.3 - 10.5 - 0. Narlhara et al (1938) Taihoku i.3b3 Chinese schoolchildren 5.5 8.3 12.2 0.8 - 15.6 - o.h Narihara et al (1938) Hokuto ** male schoolchildren 3.0 10.b 0. - - 15.2 - - Ro (19*K)) Hokuto *** female schoolchildren 1.9 11.5 3.8 - - 12.8 - - Ro (19^0) North Formosa 139 "rural persons" 11.5 13.7 2.9 — 2.2 ‘ WakeshiraaA Koo (1933) Incidence of intestinal protozoa as ascertained hy fecal examinations. TABLE XXII * 1 case with Ghiloraastix meenill. mm 0,5 percent " 11 *** 0,6 percent H " CHAPTER VIH THE ACUTE RESPIRATORY DISEASES AND TUBERCULOSIS The acute respiratory diseases appear to be the major cause of death in Formosa. In the years 1932, 1933, and 1934 approximately 25,000 deaths per year were reported as the result of these infections, yet it is likely that this figure fails to include many respiratory disease deaths. TABLE XXin Deaths from Acute Respiratory Diseases in Formosa (Japanese Year Book, 1933, 1934, 1935) Disease 1932 Rate per Deaths 1,000 1933 Rate per Deaths 1,000 1934 Rate per Deaths 1,000 Influenza 222 0.05 209 0.04 236 0.05 Bronchitis* Bronchitis, 4,980 1.08 4,855 0.96 5,143 1.02 acute 1,027 0.22 0 0. 0 0. Pneumonia 17,877 3.89 17,862 3.53 22,934 4.53 Pleurisy 1,298 0.28 1,629 0.32 1,815 0.36 ♦The figures for bronchitis appear to include also the figures for bronchitis, acute. That there is but little seasonal change in the death rates for the Is- land as a whole from the acute respiratory diseases is evidenced by the following monthly death rates for 1932 (from the Statistical Report of the Formosa Government, 1934): TABLE XXIV Disease Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Influenza 8 8 19 12 16 36 44 12 9 6 20 22 Bronchitis* 552 418 497 387 372 360 439 383 296 373 405 498 Bronchitis, acute 101 87 96 79 70 70 94 76 63 92 101 98 Pneumonia 1537 1334 1829 1609 1750 1673 1774 1361 1094 11751228 1510 Pleurisy 113 99 139 114 128 128 112 111 86 81 93 94 ♦The figures for bronchitis appear to include also the figures for bronchitis, acute. Taihoku Disease Rate Deaths per ipoo Shinchiku Rate Deaths per ;ooo Taichu Rate Deaths per 1,000 Tainan Takao Rate Rate Deaths per Deaths per 1,000 1,000 Taito Rate Deaths per 1,000 Karenko Rate Deaths per 1,000 Boko Rate Deaths per 1,000 Influenza 82 0.08 25 0.04 19 0.02 55 0.04 29 0.04 4 0.06 8 0.08 Bronchitis^980 Bronchitis, 0.99 619 0.87 1,125 1.03 1,362 1.10 736 1.09 37 0.59 60 0.63 61 0.94 acute 264 Pneu- 0.27 94 0.13 174 0.16 296 0.24 156 0.23 20 0.32 5 0.05 18 0.28 monia 3,083 3.12 1,937 2,73 4,259 3.89 5,484 4.42 2, 547 3.78 179 2.86 259 2.72 129 1.98 Pleurisy 281 0.28 86 0.12 352 0.32 390 0.31 156 0.23 4 0.06 14 0.15 15 0.23 ♦The figures for bronchitis appear to include also the figures for bronchitis, acute. The relative size of the respiratory disease problem in the different prefectures is somewhat shown by the following figures (Statistical Report of the Formosa Government, 1934): Deaths from Acute Respiratory Diseases in Formosa, 1932. TABLE XXV 28 The'respiratory disease problem would appear to be the most acute in Taichu, Tainan and Takao. It is likely that the marked and rapid variations in temperature and the heavy rainfall contribute to the high mortality from the respiratory diseases in certain localities. That the death rate from-the pneumonias is much greater in Formosa than in the United States is suggested by the following comparison for the year 1932. TABLE XXVI Death rate per Disease 1,000 population U. S. Formosa Influenza 0.30 0.05 Bronchitis 0.036 1.08 Pneumonia (all forms) 0.76 3.89 Pleurisy 0.02 0.28 It is probable, however, that since the introduction of the sulfonamides into medical practice these high pneumonia mortality rates have been favor- ably modified in Formosa as has been the case in the United States. TUBERCULOSIS Tuberculosis is a disease of considerable importance in Formosa and the decrease in tuberculosis mortality which has been evident since 1850 in the United States has apparently not occurred in Formosa. Thus we find the pulmonary tuberculosis death rate per 1,000 population recorded as 1.37 per- cent in 1906, 1.43 percent in 1916, 1.54 percent in 1926 and 1.37 percent in 1935. There has apparently been very little done in the way of public health education regarding tuberculosis and very little provision for early case finding. Our records show only one tuberculosis sanitorium. Careless disposal of sputum and congested living quarters undoubtedly contribute to the high tuberculosis death rate. 29 TABLE XXVII Deaths from Tuberculosis in Formosa, 1932 (Statistical Report of the Formosa Government, 1934) Total m Rate Deaths per 1,000 Japanese Formosa Foreigners Tuberculosis of respiratory sys- tem (including trachea, bronchi and lymph nodes)... 6,709* 1.46 291 6,341 77 Tuberculosis, pul- monary 6,511 1.42 280 6,160 71 Tuberculosis, of other organs 897 0.20 49 836 12 ♦This total apparently also includes the total for tuberculosis, pulmonary. The relatively high mortality suffered from tuberculosis in Formosa is somewhat shown in the following comparison: TABLE XXVin Death Rate per 1,000 Population, 1932 Type Formosa United States Tuberculosis (all forms) 1.66 0.628 Tuberculosis, of respi- ratory system 1.46 0.564 The distribution of tuberculosis deaths through the eight (8) prefec- tures of Formosa in 1932 is shown in Table XXX. The deaths would appear to be quite evenly distributed through the prefectures with the exception of Shinchiku. This prefecture appears to have a low rate, more comparable to that found in the United States. If we accept the commonly used thumb-rule that for every annual death from pulmonary tuberculosis at least six (6) active cases should be discoverable, it would appear that in Formosa in 1932, there were 39,066 active cases of tuberculosis. Of those active cases apparently less than one- fifth were hospitalized (see Table XXDO. 30 TABLE XXIX Tuberculosis Cases and Deaths in Government and Other Public Hospitals in Formosa, 1932 (Statistical Report of the Formosa Government, 1934) Diseases Government Hospital in-patient p°tfent Cases Deaths Cases Public Hospital Cases Total Cases Tuberculosis, pulmonary 444 97 1,339 5,667 7,450 Tuberculosis, other than pulmonary 115 13 506 793 1,414 The amount of tuberculinization of the child population can be roughly estimated from the following results obtained in 1939 in the prefecture of Taihoku. Mantoux testing of over 37,000 school children showed 24.7 per- cent of the Japanese children and 45.5 percent of the Chinese children to be tuberculin positive. 31 Disease Taihoku Shinchiku Taic hu Tainan Takao Talto Karenko Boko Deaths Rate per 1000 Deaths Rate per 1000 Deaths Rate per 1000 Deaths Rate per 1000 Deaths Rate per 1000 Deaths Rate per 1000 Deaths Rate per 1000 Deaths Rate per 1000 Tuberculosis, of respiratory system (includig trachea, bronchi, and lymph nodes) 1,424* l.U 474 0.67 1,461 1.33 2,124 1.71 1,008 1.50 72 1.15 91 0.95 55 0.85 Tuberculosis, pulmonary 1.396 i.a 466 0.66 1,420 1.30 2,052 1.65 1,069 1.59 72 1.15 90 0.94 55 0.85 Tuberculosis, of other organs 209 0.21 127 0.18 186 0.17 239 0.19 96 0.U 7 0.11 20 0.21 13 0.20 * This total also apparently includes the total for tubercul< *>sis, pulmonary. Deaths from Tuberculosis in Various Prefectures of Formosa, 1932 (Statistical Report of the Formosa Government, 1934) TABLE XXX 32 CHAPTER DC THE ACUTE INFECTIOUS DISEASES The statistics of the acute infectious diseases in Formosa are incomplete and open to question since it is admitted that many of the private physicians of the Island are remiss in reporting their cases. It is said that the resistance of many of the private practitioners to reporting their cases is based upon the fact that the policies with regard to disinfecting premises where infectious disease has occurred are extremely drastic and often involve the closing of the house and the confiscation or destruction of food and other supplies. From the League of Nations Reports the figures in Table XXXI are available. If we accept these at their face value the following conclusions would appear justified for the eight (8) Reportable Acute Infectious Diseases (small- pox, scarlet fever, diphtheria, cerebrospinal meningitis, encephalitis lethargica, plague, yellow fever, and typhus fever) through the period 1926-1938: 1. Diphtheria stood first both as to incidence and deaths and did not appear to be decreasing; its peak year was 1936. 2. Cerebrospinal fever stood second both as to incidence and deaths and did not appear to be decreasing; its peak year was 1935. 3. Scarlet fever stood third both as to incidence and deaths and did not appear to be decreasing; its peak year was 1934. 4. Smallpox had its peak year in 1926 and was definitely decreasing from 1926-1938. Between 1932 and 1938 the number of cases of smallpox reported annually was negligible. 5. The reports on encephalitis lethargica are only available for three years: 1936, 1937 and 1938; the disease was apparently increasing. 6. There were no cases of plague, yellow fever, or typhus reported through the 13-year period. Apparently the last smallpox epidemic of serious proportions occurred in 1920 when there was an outbreak of 838 cases. A slight outbreak occurred in March and April 1939 when 67 cases were reported from the prefecture of Tainan. 33 Disease 192b 192? 1928 1929 1930 1931 1932 1933 1931* 1935 193b 1937 1938 ca Cj 0) o a o a. <3 O Deaths — K a © o Deaths 1 Cases Deaths Cases Deaths as ® « S Deaths to 0) o 4 Deaths w 0) m a 0 Deaths Cases Deaths - - - — 1 Cases Deaths Cases a 43 aj v Q Smallpox 93 1 0 1 0 0 0 82 8 2 0 bl 8 1 1 5 0 2 1 2 0 0 0 0 Diphtheria 2^3 b3 1+11 7b 32k b5 385 *>7 1+02 71 w+o 10*+ 523 88 bbO 101 832 ll+l 720 125 8b5 153 803 137 915 • • • Scarlet fever b 3 9 0 12 1 25 1 23 0 58 1+ 57 1 bb 0 1+18 12 227 11 b3 5 82 3 78 e e e Oerehro- spinal meningitis 100 bl 33 21 21 Ik 33 27 11 3 10 b 10 8 20 17 272 ib7 273 lb2 198 122 98 50 lb5 e e • Encepha- litis lethar- gica • • e e e. • e e • # e e 1 1 27 9 3b • e • Plague - Yellow fever Typhus * * ... si* jjnif iee "data not yet puhl ished or received11, Heportable Acute Infectious Diseases In Formosa (League of Hations Reports)* TABLE XXXI 34 TABLE XXXII Data on Smallpox Vaccination in Formosa Year Total Positive Negative 1927 221,348 170,360 50,988 1928 203,424 184,692 18,732 1929 146,383 136,128 10,255 1930 1,058,921 575,808 483,113 1931 328,090 225,307 102,783 1932 910,519 427,163 483,356 The Japanese Year Book reports the following deaths from measles and whooping cough: TABLE XXXIH Deaths from Measles and Whooping Cough in Formosa (Japanese Year Book, 1933, 1934, 1935) Disease 1932 1933 1934 Measles 730 732 2,320 Whooping cough 393 447 525 It would appear therefore thatthenonreportable diseases, measles and whooping cough, each cause more deaths annually than does any one of the reportable acute infectious diseases (including the reportable enteric diseases but excluding diarrhoea and enteritis). The seasonal incidence of the acute infectious diseases can be some- what inferred from the following figures for 1932 (Statistical Report of the Formosa Government, 1934). (See Table XXXIV) 35 TABLE XXXIV Deaths in Formosa from Acute Infectious Diseases, 1932 Disease Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Smallpox 8 _ Measles 119 96 134 75 114 66 61 35 13 5 8 4 Scarlet Fever - 2 - - - - _ _ _ - _ Whooping Cough 18 12 26 11 26 28 55 63 29 22 45 58 Diphtheria 11 16 9 4 5 1 6 4 3 9 6 12 Meningitis (excluding tuberculous) 33 41 37 49 61 86 87 70 61 47 51 44 TABLE XXXV Acute Infectious Disease Deaths in Various Prefectures, Formosa, 1932* Disease Taihoku m B Rate cd Per P 1,000 Shinchiku w _ B Rate g per g 1,000 Taichu Tainan £ Rate || 'Rate os per Is per g 1,000 g 1,000 Takao w £ Rate g per g 1,000 Taito Karenko j9 Rate j9 Rate per per g 1,000 g 1,000 Boko £ Rate la per g 1,000 Smallpox 4 0.004 - 4 0.04 Measles 47 0.05 43 0.06 323 0.30 257 0.21 35 0.05 16 0.26 6 0.06 3 0.05 Scarlet Fever 1 0.001 1 0.01 Whooping Cough 117 0.12 35 0.05 83 0.08 104 0.08 40 0.06 - 8 0.08 6 0.09 Diphtheria 53 0.05 6 0.008 9 OjOCB 10 0.006 3 0.004 - 4 0.04 1 0.02 Meningitis 133,0.13 138 0.19 90 0.08 189 0.15 75 0.11 12 0.019 13 0.14 17 0.26 (excluding Tuberculous) Report of the Formosa Government, 1934. Though no figures showing the actual incidence, distribution and death rate are available for certain of the acute infectious diseases, it is of some interest to show the number of admissions to the Government and Public Hospitals for these diseases as in Table XXXVI. 36 TABLE XXXVI Number of Cases of Selected Acute Infectious Diseases Treated (In-patient or Out-patient) at Government or Public Hospitals, Formosa, 1932* Number of Cases Disease Treated Rabies 24 Poliomyelitis 21 Spirochetosis icterohemorrhagica., 56 Tetanus 1,143 Mumps 1,342 Erysipelas 1,096 Actinomycosis 130 ♦Statistical Report of the Formosa Government, 1934. CHAPTER X OTHER INFECTIOUS DISEASES Skin Diseases Many kinds of skin diseases have been reported from Formosa. Because of nomenclatorial difficulties and a lack of papers containing statistical data, it is not possible to indicate the relative prevalence of the different skin diseases in any degree of accuracy whatsoever. Among the fungous infections Matsumoto (1939) lists Tinea imbricata, caused by Endodermophyton cruris,from Formosa, although he makes no state- ment concerning its prevalence. According to the same author favus is a com- mon disease in the coastal areas. Yoh (1940) discussed 388 cases of fungous diseases of the head observed by him in Taihoku Prefecture. The organisms in- volved were as follows: Grubyella ferruginea (Microsporon ferrugineum). 296; Bodinium violaceum (Trichophyton violaceum), 68; Trichophyton coccidium. 23* Trichophyton glabrum, 1; and Trichophyton gypseum, 1. Takashi and Yoh (1940) studied 947 cases of head fungous infections among native children of central Formosa. The following fungi were cultured: Microsporon ferrugineum. 583; Trichophyton violaceum, 311; and Trichophyton glabrum. 31; and Trichophyton coccidium, 67. Leprosy, is quite prevalent in Formosa. Matsumoto (1935) gives the inci- dence as 0.6 percent as compared with 0.55 percent in the Japanese Mandated Islands, and 0.028 percent in Japan proper. The statistics of the Government of Formosa (1934) reveal that there were thirty-five deaths due to leprosy in 1932. Deaths due to leprosy were reported from all prefectures and districts except Karenko, indicating a general distribution of the disease throughout the island. In 1932 there were 179 hospital cases (7 deaths) recorded. Scabies is said to be common among the Chinese. Yaws. According to Asai and Chin (1940) yaws now occurs only among the aboriginal Paiwans in the southern mountains of Formosa. According to these authors 1,871 cases from 51 colonies of these natives were treated in 1932. In 1938 at Rikiriki the authors examined 1,700 of the Paiwans and found 107 with yaws. In 1939 they found 139 cases in the same region. Although salvarsan and neosalvarsan have been used extensively among these natives, there are many relapses and many cases seem to be resistant to this type of treatment. Venereal Diseases Prostitution is apparently a well-organized and common practice in For- mosa. Although periodic physical examinations of prostitutes are required, it is said that in many establishments they are given special treatment prior to the examination and are consequently pronounced free of disease. The majority of the prostitutes examined are Japanese and it appears that the profession is practiced largely by Japanese women. The following table is taken from the statistics of the Formosan Government for 1932. 38 TABLE XXXVH Prostitutes Examined in Formosa in 1932 Prefecture Japanese Formosan Chinese Korean Taihoku 20,724 58 2,071 Taichu 4,555 - 1,013 Tainan 3,751 3,561 1,374 Takao 5,969 - 1,060 Karenko 2,149 - 562 Boko 5,245 - - Total 42,393 3,619 6,080 These data may be misleading since it is possible that in attempting to protect their own personnel, the Japanese may have been more strict in enforcing physical examinations among the Japanese women. The inefficiency of the system of examination and control is indicated by the fact that only about one-tenth of one percent of the prostitutes examined are reported to have syphilis and only two to three percent to have gonorrhea. Some idea of the prevalence of venereal diseases can be obtained from the data on hospital admissions. In 1932, two percent of all hospital admissions were for gonorrhea, about one percent were for syphilis, and one half of one percent for chancroid. Trachoma Trachoma is prevalent in Formosa as well as in other parts of the Japanese Empire. Between eight and nine percent of all admissions (including out-patients) to hospitals are for trachoma. About one-tenth of one percent of the prostitutes examined from 1927 to 1932 were found to have this disease. 39 CHAPTER XI HELMINTHIASES (Except Hlariasis) Helminthiases are common in Formosa. About six percent of all hospital admissions are for intestinal parasitic infections. These conditions warrant that measures be taken to prevent, insofar as possible, these infections among Naval personnel. The helminthiases are not reportable diseases in Formosa and consequently it is necessary to ascertain their prevalence on the basis of results obtained by individual investigations and surveys. The best general sources of information on the prevalence of helminthiases are Yokogawa and Morishita (1931, 1933) and Suzuki (1929). Nematodes Nematode infections, in general, are heaviest in Taichu and Taihoku Pre- fectures, although data are incomplete from Karenko and Taito Districts. Accord- ing to Suzuki (1929) infection rates are the highest in the foothill regions where as high as 90 percent of the people may harbor one or more species of parasitic nematodes. About 80 percent of the rural population of the plain areas have nematode infections, and about 75 percent of the people of coastal rural areas harbor one or more species of parasitic round worms. Table XXXVIII gives a general summary of the results of several surveys and investigations. Hookworm. Necator americanus. Ancylostoma duodenale. and Ancylostoma braziliense are all known ot occur in Formosa. The last was not recorded until 1928 when Yokogawa (1928, 1929) found it among the aborigines in central Formosa Necator americanus seems to be more common than Ancylostoma duodenale. Ancylostomiasis incidence varies from less than one percent in urban centers to more than sixty percent in rural areas. The highest incidence of ancylosto- miasis is found in Taichu prefecture. In this prefecture the rate for the foothill country is 62.8 percent; for the valleys, 60.8 percent; for the plains, 57.6 percent; and in coastal areas 53.7 percent. The second heaviest rate is that of Taihoku. In this prefecture the rate is 27.4 percent in the valleys, 27.5 percent in the foothills, 26.1 percent in the plains, and six percent along the coast. In Takao Prefecture infection rates of 13.5 percent to 17.5 percent were found. In Tainan the rate is 8.6 percent in the plains region (most of the prefecture). Ancylosto- miasis was found to be rare in Shinchiku Prefecture by Suzuki (1929). Oi (1927) records ah incidence of 14.5 percent for the Loochoo Islands. Ohama (1940) recorded an incidence of 93 percent on Isigaki Island in the Loochoo Archipelago. Ascaris lumbricoides. Ascariasis is the most common helminthiasis in Formosa. Rates from 22 percent to 95 percent, varying according to locality and class of people examined, have been recorded. -Suzuki (1929) found 75.77 percent of 39,675 persons examined to be harboring this nematode. After six years, age seems to exert little influence on the rate of infection. Ascariasis is slightly more prevalent in the valleys and foothills (over 82 percent) than in rural districts along the coasts (74.5 percent) and on the plains (68.6 percent). Ascariasis is more common in Taichu than in the other prefectures; Taihoku is next. High rates have also been observed in parts of Karenko District. 40 Locality Number Examined Description Hookworm Ascaris lumbricoides Trichuris trichiura Enterobius vermicularis Strongyloides stercoralis Reference Per- cent Per- cent Per- cent Per- cent Per- cent Talhoku City 971 Japanese schoolchildren 1.0 22.2 22.1 1.6 Narihara et al (193$ Taihoku " 1.363 Chinese schoolchildren 2.2 53.6 37.8 1.5 - Narihara et al (193$) 1*4.34. hospitalized children 1.0 78.1 23.4 6.8 - Muto (1940) Shlnohiku 2,000 general population 15.0 94.5 - - - lokogawa et al (1926) Talhoku 555 outpatients 13.0 35.0 46.5 2.9 1.3 Yamazaki (1925) Karenko District 716 general population 3 vfflages 56.0 59.5 74.7 0.6 0. 0i (1927) Yoshino (Karenko) 243 schoolchildren 30.0 90.0 86.5 0,8 0. 01 (1927) Karenko City 220 hospital patients 25.4 44.0 52.0 0.9 0.4 0i (1927) Karenko " 40 fishermen 20.0 45.0 87.5 0. 0. 0i (1927) Karenko " 168 schoolchildren 52.2 82.7 88,0 1.2 2.4 0i (1927) Karenko District 104 "nativesM of plains 55.8 77.8 88.4 1.8 0. 0i (1927) Karenko " 77 "natives" of highlands 75.3 20.7 50.7 3. 0. Oi (1927) Taihoku City 259 medical students 7.8 22.7 - - - Morioka et al (1936) Tainan Prefecture 1,688 residents of foothills 10.5 64.5 22.4 0. 0. Suzuki (1929) Tainan n 5,312 " " plains 18,6 63.9 44.2 0. 0. Suzuki (1929) Taichu " 3.896 " " foothills 24.5 90.4 96.1 0.1 0.1 Suzuki (1929) Taichu " 2,808 " " plains 57.6 92.8 95.2 0.1 0,3 Suzuki (1929) Taichu n 2,522 " " coast 53.7 90.4 92.5 0.1 - Suzuki (1929) Taichu " 5.627 " " valleys 60.1 94.0 95.4 0.1 0.1 Suzuki (1929) Shinchiku " 1,195 " " foothills 0.1 50.6 15.2 0. 0. Suzuki (1929) Shinchiku " 2,003 " 11 plains 0.1 51.2 12.3 0. 0. Suzuki (1929) Taihoku " 1,663 " " foothills 27,5 94.8 44.3 0.2 0. Suzuki (1929) Taihoku " 2,680 " " plains 25.3 88.5 50.7 0. 0.2 Suzuki (1929) Taihoku M 2,129 " " coast 6.0 55.6 13.5 0. - Suzuki (1929) 'aihoku " 1,354 " " valleys 27.4 85.4 12.7 0. 0. Suzuki (1929) Prevalence of Parasitic Nematodes as determined by fecal examinations TABLE XXXVIII 41 Trichuris trichiura. The prevalence of whipworm infection, as determined by stool examinations, is similar to that of ascariasis. Rates from 12 percent to 95 percent were recorded by Suzuki (1929). According to this investigator 52.8 percent of the entire population harbors whipworm. Taichu Prefecture has by far the greatest incidence, 93 to 96 percent. In Taihoku Prefecture the incidence varies from 12.7 percent in the valleys to 50.7 percent in the plains; along the coast it is 13.5 percent. In Tainan the rates vary from 23 percent in the valleys and foothills to 44 percent on the plains. In Shinchiku 12 to 15 percent was observed and the rate for the plains of Takao Prefecture was found to be 19.4 percent. Trichiuriasis is also common in Karenko District. Enter obius vermicular is. This species is relatively rare with infection rates from less than one percent to seven percent according to various surveys. Suzuki (1929) found Enterobius in 0.05 percent of all fecal samples examined. Strongyloides stercoralis. Infection rates as high as 2.4 percent have been found. In more than 39,000 examinations Suzuki (1929) found only 0.06 percent with Strongyloides. Trichostrongylus orientalis. This parasite is relatively rare. Suzuki (1929) found only 0.02 percent of the people infected with it. Cestodes Taenia saginata. This tapeworm is described by Yokogawa and Morishita (1931, 1933) as common in Formosa. It can be safely assumed that most of the cases of taeniasis reported by various authors are caused by Taenia saginata. Yokogawa et al (1928) found eggs or proglottids in 10.3 percent of the stool examinations made in Shinchiku Prefecture. In more than 30,000 examinations in all parts of the island Suzuki (1929) found 0.32 percent with tapeworms. Taenia soliurm Yokogawa and Morishita (1931, 1933) state that only one case of taeniasis due to this species of cestode worm is recorded from Formosa. Hymenolepis diminuta. Yokogawa and Wakejima (1932) described this ces- tode as rare among the school children of Formosa. Normally a parasite of rats there are scattered records of its occurrence in humans in Formosa. Hymenolepis nana. As In other areas this species is more frequently found in man in Formosa than is Hymenolepis diminuta. Mayeozoka (1935) examined 4,931 aboriginal children, 1,948 Chinese children, and 739 Japanese children in Taito Prefecture and found this very common (10-40 percent); it was noted as rare in adults. Diphyllobothrium mansoni. This species has been recorded in man several times from Formosa. In these infections man plays the role of an accidental second intermediate host by drinking water containing infected Cyclops, a fresh-water copepod, or by the direct entry of the larva through cutaneous lesions. The resulting plerocercoid larva may develop in any part of the body. The definitive hosts are dogs, cats, and wild carnivora. Suzuki (1929) found nine cases in the foothills. 42 w *h 3 *H 3 g CO •H 7 1934 5.194,980 77 7 210 2 21 b 19 b 33 11 1 - - - 57 7 418 39 80.4b 9.33 1935 5.315.642 110 4 23 b 2 20 5 le 2 38 lb 3 - - - 3b b 4b2 35 8b. 91 7.58 193b 5.^51,8b3 102 12 205 b 13 2 23 4 44 15 2 - - - 30 5 419 44 7b.8*5 10.50 1937 . 5,b09,o42 102 b 212 - 1^ U 20 - Sb l4 2 - - - 30 2 436 Pb 77.73 5.9b 1938 5,7^,959 120 10 193 - l4 4 24 3 42 7 - - - - 28 5 421 29 73.2b b.89 Total 1904- 1938 lU2,388,580 3.283 275 5.987 54 2k0 58 593 87 894 20b 45 1 3 - 1,600 158 12645 839. 88.81 b.b4 Annua] aver- 4,068,245.14 93.80 7.8b 1710b 1.54 b.8b l.bb lb.94 2.49 25.54 5.89 1.29 0.03 0.09 - 45.71 4.51 3b3.29 23.97 age Incidence uer 1,000 ,000 •nouulation 23.0b 1.93 4205 Q_»38 ljb9 0.41 4.1b O.bl b.28 i±45. 0, J2 0.01 0.02 31.24 1.11 88.81 5.JS9 Case fatality 8.38 0.90 24.17 14. b7 23.04 2 .22 - 9.88 b.b4 Percent by species 25.9b 32.78 47-35 b .44 1.90 b.91 4.69 10.37 7.07 24.55 0.3b 0.12 0.02 12.65 18.83 ino.00 100.00 1. Cases of snake-Mtes and deaths therefrom in Formosa In (from To, 19^1) D3 Prefecture and district T. mucro- squa- matus 1 T. grami- neus A. acutus Naja naja atra B. multi- cinc- tus V. russellii formo- sensis Un- known Total Annual average Per- cent Taihoku 880 1,055 28 39 168 2 145 2,317 115.85 27.06 Shinchiku 305 7^9 28 38 103 1 162 1,386 69.30 16.19 Taichu 206 262 21 83 118 3 116 809 40.45 9.44 Tainan 135 ui 4 52 69 1 84 486 24.30 5.68 Takao 345 711 55 67 83 2 130 1,395 69.75 16.29 Taito 662 47 57 50 4 189 1,155 57.75 13.49 Karenko 162 520 31 53 47 29 173 1,015 50.75 11.85 Total 2,181 4,100 214 389 638 42 999 8,563 428.15 100.00 Annual average 109.05 205.00 10,70 19.45 31.90 2.10 49.95 428.15 Percent by species 25.47 47.88 2.50 4.54 7.45 0.49 11.67 100.00 2. Cases of snake-bites in different prefectures of Formosa in 1919-1938 (from To, 1941)* Habitat Jan Feb Mar Apr May June July Aug Sept Oct Nov Deo Total Annual average Percent Mountain forest 32 29 50 91 166 194 193 229 201 173 104 42 1,504 83.56 19.12 Plain 10 9 26 43 71 100 92 120 129 83 59 21 763 42.39 9.70 Rice field 15 7 27 38 66 82 106 110 83 94 61 18 707 39.28 8.99 Dry field 22 26 43 109 162 222 202 205 193 175 104 55 1,518 84.33 19.29 Roads 18 11 a 74 152 170 218 219 243 204 97 40 1,487 82.61 18.90 River 1 3 7 14 35 36 53 46 36 28 17 9 285 15.83 3.62 House 16 23 21 46 126 134 158 174 176 119 73 24 1,090 60.56 13.85 Unknown 10 7 15 27 67 69 59 87 64 55 a 13 514 28.56 6.53 Total 124 115 230 442 845 1,007 1,081 1,190 1,125 931 556 222 7,868 437.11 100.00 3* Seasonal distribution of the cases of snake-bites according to habitat 1921-1938 (from To, 1941)* D5 Key to Formosan Terrestrial Poisonous Snakes (Systematic arrangement according to Maki, 1931) 1, Ectopterygoid bone absent; teeth In upper jaw only .. Fam, Typhlopidae* Ectopterygoid bone present; teeth In both Jaws 2 2, Maxillary horizontal; a mental groove present or absent 3 Maxillary vertically erectile 9 3* A mental groove present 4 A mental groove absent Fam. Amblyoephalldae* A* Anterior maxillary teeth not grooved nor perforated •• Fam. Colubridae* Anterior maxillary teeth grooved or perforated Fam, Elapidae 5 5* Median dorsal scale row enlarged, hexagonal* subcaudals single Bungarua multlclnctus Median dorsal scale row not enlarged* subcaudals divided 6 6. Vertebrae with long ribs which enable the distention of neck; scales in 21 to 23 rows on body Na.1a na.1a atra No elongated ribs on cervical vertebrae; scales in 13 to 1$ rows on body 7 7. Two small solid teeth on maxillary behind a pair of large grooved fangs •••••••••••.•••• ••••••••• 8 No teeth on maxillary behind a pair of fangs Callloohis macclellandii formosensls 8. Dark crimson red above with three broad black longitudinal stripes; ventrals from 249 to 269 Hemibungarus sauteri sauteri Dark crimson red above with three broad black longitudinal stripes; the lateral ones being interrupted by black cross-bands edged by narrow white markings; ventrals from 238 to 248 ••••• Hemibungarus sauteri batorii 9* Loreal pit absent Fam. Viperidae Vioera russellii formosensis Loreal pit present Fam. Crotalidae 10 10, Head abovfc covered with large symmetrical shields ...Genus Agklstrodon 11 Head above covered with small scales Genus Trimeresurus 12 11, Anterior subcaudals unpaired; snout ending in an upward pointed appendage; ventrals 162-168 A, acutus All subcaudals paired; snout not turned upward; ventrals 132-156 A. halva blomhoffii * All typhlopids are non-poisonous , some of the colubrids and amblycephalids are more or less poisonous but their habit Is so Inobtruslve that they are rarely In conflict with man. D6 12. Tall prehensile; nostril in a single nasal; color in life yellowish green, green or bluish green above 13 Tail not or but slightly prehensile; nostril between two nasals or in half divided nasal; color in life brownish, with dark brown spots 15 13. The third upper labial broadly in contact with the subocular; with a lateral whitish line on each side of body 14 The third upper labial separated from the subocular by a series of scales; no lateral line on each side of body T, gramineus kodairai 14, With a red line below the lateral whitish line on each side of body •••• T, gramineus formosensis Without a red line below the lateral whitish line on each side of body T. gramineus ste.inegeri 15. The first lower labial divided; the second upper labial separated from the loreal by the prefoveal shield* scales in 17 - 21 rows around middle of body T, gracilis The first lower labial not divided; the second upper labial forming the anterior border of the loreal pit; scales in 25 - 30 rows around middle of body •••• 16 16. Internasals in contact behind the rostral* ventrals 140 - 155; subcaudals 40 to 55; about 8 scales between supraoculars T. monticola orientalis Internasals separated by two or three scales behind the rostral; ventrals more than 200; subcaudals 60 to 95 > scales between supraoculars 12 - 18 T. mucrosquamatus D7 APPENDIX E CHECKLIST OF THE MURIDAE OF FORMOSA Checklist of the Muridae of Formosa The following list, together with the collecting localities has been compiled from Kuroda’s (1938) list of Japanese mammals. The nomenclature as used by this author has not been modified. Rodents other than the murid species have not been included since there is no evidence that any of them are of medical importance. Naturally not all of the species are listed here; how- ever, it was thought to be desirable to present a complete checklist. The localities recorded here are those for Formosa only. 1. Microtus kikuchii Kuroda, 1920 Localities: Collected only at altitudes over 6000 feet. 2. Eothenomys melanogaster (Milne-Edwards), ssp.? Localities: Arisan, Shikayosha, TOseigun. 3. Apodemus agrarius ningpoensis (Swinhoe), 1870 Localities: Baksa, Taihoku, Kagi. 4. Apodemus semotus Thomas, 1908 Localities: Collected at higher altitudes in all parts of the island. 5. Micro my s minutus Tokuda & Kano, ssp., 1937 Localities: Tamsuy (Tamsui), Shikayosha, Rumanoansha. 6. Rattus rattus rattus (Linnaeus). 1758 Localities: None given. 7. Rattus rattus alexandrinus (Geoffroy), 1803 Localities: Tamsui, Suiriko, Tainan, Riran. 8. Rattus rattus rufescens (Gray), 1837 Localities: Common in houses throughout the island. Pescadores (Boko) Islands. 9. Rattus coxinga (Swinhoe), 1864 Localities: Collected in all parts of the island from lowlands to 8000 feet. 10. Rattus culturatus Thomas, 1917 Localities: Collected from all parts of island at altitudes above 7000 feet. 11. Rattus lose a CSwinhoe), 1870 Localities: Tamsui, Boryo, Bokusa. 12. Rattus norvegicus norvegicus (Erxleben), 1777 Localities: Reported as common inside and outside of houses in Taihoku. 13, Mus musculus taiwanus Horikawa, 1929 Localities: Reported from Taihoku, Shinchiku, and Taichu Prefectures; Karenko District; Boko Islands. 14. Mus formosanus Kuroda. 1925 Localities: Taihoku, Horigai. 15. Bandicota nemorivaga (Hodgson), 1836 Localities: Probafcly an introduced species. Now reported from all parts of the island. E3 APPENDIX F A LIST OF FORMOSAN TICKS F1 A List of Formosan Ticks This list has been compiled largely from Ogura (1936) and Sugimoto (1937)* It should not be regarded as a complete checklist since the literature has not been examined in its entirety* The nomenclature is, in general, that of the above authors* Notes on hosts and distribution refer to Formosa only. 1. Boophilus (Uroboophilus) annulatus australis (Puller), 1899 Hosts : sheep, cattle, water buffalo, goats, dogs, rabbit, man Records: throughout Formosa and the Loochoo Islands. 2. Boophilus (Uroboophllua) annulstus caudatus (Neumann), 1897 Hosts : cattle, water buffalo Records: no localities given. 3# Boophilua (Uroboophilus) dlstans Minning, 1934 Hosts : cattle, goats, sheep, water buffalo Records: no localities given. 4* Amblyomma testudinarlum C* L« Koch, 1844 Hosts : cattle, water buffalo, pigs, wild hogs Records: Taihoku (?), Taiohu Prefecture, Tainan Prefecture, Takao Prefecture. 5. Amblyomma cyprlum Koch and Neumann, 1899 Hosts : turtles, cattle, water buffalo Records: no localities given. 6. Amblyomma formosanua Schultze, 1933 Hosts : turtles Records: locality data not available. 7. Amblyomma yajimal Kishida, 1935 Hosts : water buffalo Records: recorded only from Formosa. 8. Haemapbysalis formosensis Neumann, 1913 Hosts : dogs, wild hogs, deer, bear Records: Talhoku Prefecture, Taito District, Takao Prefecture. 9* Haemapbysalis flaya Neumann, 1897 Hosts: horses, wild hogs, deer, dogs, cattle Records: Taihoku Prefecture, Karenko District, Taito District. F2 10. Haemaphvsalis hvstricis Supino, 1897 Hosts : dogs, deer, wild hogs, bear, etc. Records: Tait5 District, Taihoku Prefecture, Loochoo Islands. 11, Haemaphvsalis inermls Birula, 1895 Hosts : deer, cattle, fox, dogs, etc. Records: Taihoku Prefecture, 12. Haemaphvsalis mlshiyamai Sugimoto, 1935 Hosts : man, wild hogs, deer Records: Taihoku Prefecture, Karenko District, Taito District (?), 13. Haemaphvsalis fomosensis Neumann, 1913 Hosts : dog, wild hog Records: no localities given. 14. Haemaphvsalis birm&niae Supino, 1897 Hosts : many species of mammals Records: no localities given. 15. Haemaphysails blspinosa Neumann, 1897 Hosts : man, many species of birds and mammals Records: no locality data available. 16. Rhlplcepbalus sanguineus Latreille, 1806 Hosts : dogs, cattle, water buffalo Records: no locality data available. 17. Dermacentor taivanensls Sugimoto, 1935 Hosts: wild hog Records: Taihoku Prefecture, Taichu Prefecture, Taito District. 18. Dermacentor atroslgnatus Neumann, 1906 Hosts : man, dog, water buffalo Records: reported from Taichu Prefecture only. 19. Ixodes acutitarsus (Karsch), 1880 Hosts : dogs, cattle, man, wild hog Records: TaitS District, Takao Prefecture, 20. Ixodes shinchlkuensis Sugimoto, 1937 Hosts : dogs Records: Formosa only, Shinchiku Prefecture (4»000 feet). 21, Ixodes taivanensls Sugimoto, 1937 Hosts s deer, dogs, cats, wild hogs Records: Taichu Prefecture, Shinchiku Prefecture, Taihoku Prefecture. F3 22. Ixodes ricinus (Linnaeus), 1758 Hosts : many species of homolothemic vertebrates including man Records: none available; var. nivazaklenBls Sugimoto, 1937, occurs on the Looohoo Islands. 23. Indocentor bellulus Schulze, 1935 Hosts t 7 Records: no specific localities given. 24. Afgaa persicus Oken, 1818 Hosts : domestic and wild birds, cattle, man Records! there are no records of this species in Formosa; however, because of its cosmopolitan association with the domestic fowl its presence in Formosa is not unlikely. F4 A SUPPLEMENT TO THE EPIDEMIOLOGY OF DISEASES OF NAVAL IMPORTANCE IN FORMOSA (NAVMED 266) NAVMED 460 Bureau of Medicine and Surgery Preventive Medicine Division Epidemic Disease Control Section September 13, 1944 TABLE OF CONTENTS* Page Chapter I Hospitals, Physicians and Other Medical Workers 2 II Malaria 4 V Rickettsioses 5 VII Enteric Diseases 6 VIII The Acute Respiratory Diseases and Tuberculosis 15 IX The Acute Infectious Diseases 17 X Other Infectious Diseases 25 XI Helminthiases 31 Bibliography 33 Appendix - Poisonous Plants 38 A SUPPLEMENT TO THE EPIDEMIOLOGY OF DISEASES OF NAVAL IMPORTANCE IN FORMOSA Since the publication of the Epidemiology of Diseases of Naval Im- portance in Formosa CNavMed 266) additional information has become available. Because this information adds much to the communicable disease picture in Formosa, it was considered desirable to make it available in the form of a supplement. The sequence of this supple- ment follows as closely as possible that of the original manual. Bureau of Medicine and Surgery Preventive Medicine Division Epidemic Disease Control Section September 13, 1944 HOSPITALS, PHYSICIANS, AND OTHER MEDICAL WORKERS (Chapter D There was a distinct increase in the medical personnel in the years preceding the outbreak of the Pacific war. The Government-General of For- mosa in 1938 gave data regarding the prefectural distribution of hospitals, physicians and other medical workers (Table D, The Dome! News Agency (Dome! Jiji Nenkan, 1943) reported that in 1940 there were 12 government hospitals in the principal cities. Public phy- sicians subsidized by the government were in charge of the medical affairs in certain areas; The ratio of physicians to the population was one (1) to 2,400. The following were the statistics at the end of 1940: Government { llo spitals - ( Private 14 Physicians 2,401 Midwives 2,026 21 General Practitioners 133 263 Dentists 466 Nurses 349 TABLE I Prefectural Distribution of Hospitals, Physicians and Other Medical Workers in Formosa in 1938 (Taiwan Jijo, 1939) Shin- Taihoku chiku Taichu Tainan Takao Taito Karenko Boko Total. Government Hospitals Public Hospitals Private Hospitals 5 5 70 1 1 11 1 2 52 2 4 67 2 4 22 1 1 2 16 1 14 18 238 Government 78 4 ~r~ 5 6 - 1 1 99 h Hospitals 118 11 24 49 22 5 8 4 241 Public Hospitals 37 1 4 4 . 1 - 2 1 50 ? oPractitioners Public * 306 107 294 387 182 7 28 10 1,321 43 37 47 54 43 18 24 6 272 General Practitioners** 24 ~63" 29 30 17 - - - 163 ■g Government 3 - - - - - - - 3 £ Government Hospitals 8 - - 2 - - - - 10 g Public Hospitals q Practitioner - - - - - - - - - 96 32 87 99 63 3 9 5 394 Midwives 337 140 347 568 325 19 22 1,796 Nurses 142 - 5 16 3 - - 4 170 Tooth Extractors (?) 1 - - - - - - 1 2 Specialists in acupuncture Specialists in using moxa 68 5 21 74 36 1 5 2 212 cautery 72 5 21 66 26 1 5 1 197 Osteopaths 204 13 68 123 63 9 10 4 494 Masseurs 41 3 9 46 20 1 2 1 123 Stomach specialists (?) 19 - 4 10 5 1 2 - 41 Specialists in bone setting 2 - - 2 10 1 1 - 16 r* wGovernment 12 2 ~T~ ~Z~ 1 1 1 2 Hospitals 16 3 5 9 5 2 2 2 44 j3 o Public Hospitals 6 - - 1 1. - 2 - 10 Ph Practitioner 28 12 17 32 34 3 5 - 131 Druggists 137 ~2T 38 90 11 8 12 4 324 Druggists (Chinese herbs) 302 236 487 542 271 11 39 29 1,917 Drug manufacturers Manufacturers of patent 16 1 - 6 - - - - 24 medicine 155 99 202 299 96 6 10 9 876 Sellers of patent medicine 1,279 678 1,448 1,741 1,021 116 209 72 6,5 64 Medicine peddlers 928 1,028 1.773 1,962 786 20 132 43 6,672 * Public physicians are physicians subsidized by the government and placed in charge of medical affairs in certain areas. **General practitioners are those persons in the private practice of medicine whose training and professional standing are somewhat below that of the physician practi- tioners. MALARIA (Chapter II) There were some studies done on malaria in Formosa in the later thirties but most of them were on its control and remedies. No statistics available except the 3,782 deaths (2,007 males and 1,775 females) reported by the Depart- ment of Overseas Affairs in 1935 (Tomuku Tokei, 1937). Results of blood exami- nations for Plasmodia in Formosa from 1934 to 1938 are given in Table II. TABLE II Result of Blood Examinations (Taiwan Jiji, 1939) Year Number of Places Examined Number of Persons Examined Number of Malaria Carriers Percent of Carriers 1934 164 2,618,668 72,307 2.76 1935 169 2,559,399 78,909 3.08 1936 187 2,771,841 83,991 3.03 1937 186 2,811,820 85,575 3.04 1938 190 3,273,543 107,246 3.26 Miyabara (1937) reported that 958 of the 1,600 population on Botel Tobago were examined and 634 (66.2 percent) were found to have enlarged spleen and 153 (16 percent) were found to harbor Plasmodia. Maruyama (1935) found that 36.8 percent of the Yami population on Botel Tobago had splenomegaly and that the splenomegaly index among the children below 15 years of age was as high as 60-70 percent. Omori (1937) recorded three (3) species of Anopheles from this island, viz., sinensis, minimus and maculatus. The relative prevalence of the three (3) species of Plasmodium vivax: malariae: falciparum in Formosa was 46:9:45 according to Hatori and Kinoehita and 43:9:48 according to the Sanitary Division of the Police Bureau of the For- mosa Government (1935). However, Miyabara (1937) found that in Botel Tobago 41 percent were vivax. 35 percent were malaria and 24 percent were falciparum. This situation indicates that p. malar iae is important in Botel Tobago though it is not so in the main island. 5 RICKETTSIOSES (Chapter V) Two-Week Fever. As early as 1908, Horiuchi et al reported from Taihoku 29 cases of an unknown fever which according to these workers was similar to typhoid fever but could be differentiated by serum reaction. In 1911 Kato reported two (2) cases of typhus-like fever from Kagi region (Aisan). Cases of more or less the same nature were also reported from Karenko, Takao, TaitO, and B3ko under various names, such as “unknown fever”, “sporadic typhus”, “mild type typhus” and “two-week fever”. It is not possible to determine whether or not all the re- ported cases were the same disease. However, the so-called two-week fever as described by the later workers is widespread on the island. Shimokawa and Gabe (1940) made clinical studies of 147 cases- (117 males and 30 females) in the Laboratory of Internal Medicine, Medical College,. Taihoku Imperial University, and reported that headache was the most common initial symptom with anorexia and fatigue ranking next. Most of the cases had chills but only a few were accompanied with shivering. Among other symptoms there were insomnia, backache, sore throat, diarrhoea, muscular pain, nausea and vomiting. The duration of the fever is from seven (7) to 19 days and 121 cases had the fever for 12-17 days, averaging 14.136+0.193 days. One hundred and one cases had a temperature of 39.1-40.CPC. with an average of 39.438+0.436° C. According to Kaku (1940) the Rickettsia from the patients of the two-week fever reacted positively only with proteus strains OX19 and HX19 but negatively with both strains X2 and XK. Kyu (1934, 1937) made extensive studies on the transmission of the disease. Rats were collected from the endemic areas in Taihoku for experimental investi- gations and various blood sucking insects were tested. He concluded that in For- mosa the natural carriers of the organism responsible for the disease are Rattus rattus rufescens and Rattus norvegicus both of which are common on the island. Of the blood sucking insects which live on these rats, the rat fleas, Xenopsylla cheopis and Ctenocephalus felis, are the most easily infected and are undoubtedly the main agents in the transmission of the virus not only among the rats, but also from rat to man. Leptosylla musculi is probably rarely capable of trans- mitting the virus from rat to rat but not from rat to man. The body louse, Pedi- culus humanus corporis, may be infected but with difficulty. This may account for the situation that the disease is not prevalent among the aborigines where this louse is mostly found and is comparatively frequent among people who do not harbor this parasite. 6 ENTERIC DISEASES (Chapter VID Diarrhoea and Enteritis. Twelve thousand eight hundred and seventy eight (12,878) deaths due to diarrhoea and enteritis in 1935 were reported by the Department of Overseas Affairs of Japan (Tomuku Tokei, 1937); 6,483 were males and 6,395 were females. Typhoid Fever and Paratyphoid Fever. The official report of the For- mosa Government (Taiwan Sotokufuho, 1940-1941) gives the following figures for the incidence of typhoid fever and paratyphoid fever in Formosa in 1940 and 1941: 1940 1941 (Jan.-July) Cases Cases Deaths Typhoid Fever 2066 1005 185 Paratyphoid Fever 114 52 14 The prefectural and seasonal distribution of the two diseases is shown in the following tables: TABLE HI Prefectural Distribution of Typhoid Fever in Formosa from May 1940 to April 1941 Taihoko Shinchiku Taichu Tainan Takao Tait5 Karenko Boko Total 1940 May 51 3 11 33 50 4 4 156 June 95 6 14 39 47 - 7 2 210 July 128 14 26 31 46 - 10 1 256 Aug. 151 10 30 33 48 - 14 2 288 Sept. 79 8 .25 36 44 1 7 1 201 Oct. 106 12 23 35 47 - - - 223 Nov. 93 11 15 26 39 _ 4 - 188 Dec. 95 4 9 20 34 - 10 - 172 1941 Jan. 57 2 20 7 33 - w 4 3 126 Feb. 38 - 4 10 37 - 3 - 92 Mar. 31 2 11 22 25 - 5 1 97 Apr. 31 2 9 19 44 - 5 - 110 Total 955 74 197 311 494 1 73 14 2,119 TABLE IV Prefeetural Distribution of Paratyphoid Fever in Formosa from May 1940 to April 1940 Taihoku Shine hiku Taichu Tainan Takao Taito Karenko B(3ko Total 1940 May 6 1 1 1 9 June 11 1 - 1 2 - - - 15 July 12 1 - 1 2 - - - 16 Aug. 17 - - - - - - - 17 Sept. 8 - 1 1 1 - - 1 12 Oct. 8 - - - 1 - - - 9 Nov. 5 - - - 1 - - 1 7 Dec. 9 - - - - - - - 9 1941 Jan. 3 — _ 1 • • 4 Feb. 3 - - - 2 - - - 5 Mar. 4 - - 1 4 - - - 9 Apr. 1 - - - 2 - - - 3 Total 87 2 1 B 17 - - 3 115 Ri (1937) reported an epidemic of typhoid fever in Taihoku City in 1936 About 90 cases were admitted to the Pediatrics Department 'of Taihoku Hospital, with 14 deaths (15.6 percent). In Shinchiku Prefecture 239 cases of typhoid fever occurred from 1932 to 1937 (Kinugasa 1938). According to Ko (1938) 1,108 patients were admitted to the Taichu Hospital within a period of three (3) years from 1934 to 1936. One hundred eighty two (182) cases (16.4 percent) were infantile typhoid fever; 141 Japanese and 41 Formosans. Asahi and Aida (1937) gave the following statistics for typhoid fever in Taichu City from 1927 to 1936: TABLE V ■ Cases and Deaths of Typhoid Fever in Taichu City Per 10,000 Year Population Incidence Population Deaths Percent Mortality 1927 45,044 23 5.1 7 30 1928 47,947 33 6.8 10 30 1929 50,750 44 8.6 9 20 1930 54,209 57 10.5 23 40 1931 57,359 37 6.4 10 27 1932 61,857 35 5.6 8 22 1933 64,991 37 5.6 10 27 1934 68,414 73 10.6 16 21 1935 71,742 125 17.4 23 18 1936 74,839 133 17.7 19 14 Average 64,006 59.9 9.4 13.7 24.9 So (1935) reported 51 in-patient cases of infantile typhoid fever in Tainan area from 1933 to 1935. One hundred thirty two (132) infantile cases of typhoid and eight (8) infantile cases of paratyphoid were admitted to the Takao Hospital within a period of five (5) years from 1930 to 1935 (Ko, 1936). Their distribution ac- cording to sex was: typhoid, 54.5 percent male, and 45.5 percent female; paratyphoid, 87.5 percent male, 12.5 percent female. In Kagi (Kubota, 1940) there were recorded 162 cases of typhoid fever treated in Kagi Hospital from 1937 to 1939. Among these there were 46 deaths, the case fatality being 28.40 percent. In Karenko District, reported typhoid cases were comparatively few. There were only ten (10) cases from 1931 up to June 1932 (Matsumoto, 1937); there were nine (9) cases occurring in Karenko-Kai in June and 31 in Yoshino village from July to December, 1932. The distance between the two localities is about four (4) kilometers. In Boko Islands 81 cases of typhoid fever and seven (7) cases of para- typhoid fever were reported from 1933 to 1937 (Watanabe, 1938). Their annual distribution was as follows: 1933 1934 1935 1936 1937 Total Typhoid 9 19 12 23 18 81 Paratyphoid 2 4 1 7 Taichu Taihoku Tainan Kiirun Takao Kagi Shinchiku ShOka Heito Year Cases Rate Cases Rate Cases Rate Cases Rate Cases Rate Cases Rate Cases Rate Cases Rate Cases Rate 1927 23 5.1 425 19.8 77 8.8 53 7.9 34 6.7 8 3.8 31 10.2 1928 33 6.8 565 25.3 89 9.9 139 20.1 46 8.5 60 11.6 5 2.3 49 15.4 1929 44 8.6 484 20.7 77 8.3 90 12.4 71 12.0 51 9.4 2 0.9 30 9.0 1930 57 10.5 565 23.1 72 7.7 114 15.-2 80 12.3 63 10.8 22 4.6 2 0.8 19 5.4 1931 37 6.4 261 10.1 77 7.7 42 5.3 108 16.1 47 7.3 23 4.7 0 0. 32 8.7 1932 35 5.6 358 13.4 43 4.1 53 6.5 34 4.6 42 6.6 8 1.5 1 0.3 20 5.3 1933 37 5.6 224 8.1 76 7.1 63 7.7 42 5.4 64 9.5 18 3.4 1 0.2 26 6.6 1934 73 10.6 345 12.1 55 5.0 46 5.4 80 9.8 28 3.9 33 6.0 7 1.3 30 7.1 1935 125 17.4 329 11.4 115 10.2 61 6.9 105 12.0 21 2.8 59 11.0 10 1.9 30 6.8 1936 133 17.7 411 14.0 37 3.1 128 14.2 85 9.0 15 L9 34 6.1 25 4.6 16 3.4 The distribution of incidence and mortality rate per 10,000 population of typhoid fever in the important cities of Formosa is shown in Table VI. Typhoid Fever in Some Formosan Cities (Aschi and Aida, 1937) TABLE VI 10 Dysentery. In the official report of the Formosan Government (Taiwan Sotokufuho, 1940-1941) 454 cases of dysentery were listed in Formosa in 1940 and 300 cases and 60 deaths in the first seven months of 1941. The prefectural and seasonal distribution of the disease is here given for a period of a year, May 1940 to April 1941: TABLE VII Prefectural Distribution of Dysentery in Formosa from May 1940 to April 1941 Taihoku Shinchiku Taichu Tainan Takao Taito Karenko Boko Total 1940 May 33 4 4 3 1 45 June 37 2 2 3 - - - 4 48 July 33 2 1 1 - - - 1 38 Aug. 46 - 1 - 4 - 1 1 53 Sept. 41 1 2 1 2 1 1 1 50 Oct. 37 - 1 7 4 - 1 - 50 Nov. 37 - 1 6 10 - - 1 55 Dec. 17 - - 3 1 - 1 3 25 1941 Jan. 7 — 2 1 1 _ _ 2 13 Feb. 12 1 1 3 4 1 - - 22 Mar. 12 - - 11 4 - 1 - 28 Apr. 22 1 - 4 9 1 2 2 41 Total 334 11 15 40 42 3 8 15 468 The incidence of bacillary dysentery in the important cities of Formosa is shown in Table VIII. According to Shimada (1936) dysentery was rather common among the children in Taihoku. There was an average of about 60 cases every year, being about five (5) percent of the total patients in the Pediatrics Department of Taihoku Hospital. .Most of the cases occurred in May and were Japanese of the ages 2-7 years. About 72.5 percent of the cases were bacillary dysentery. Of this 93.9 percent were of the atypical type, 7.3 percent of Ohara type and only 0.3 percent of Shiga type. There were only one-twentieth as many amoebic cases as bacillary cases. 11 TABLE YE! Bacillary Dysentery in Formosan Cities (Kojima et al, 1940) City Number of Cases 1934' 1935 1936 1937 1938 Average Rate per 10,000 Population 1934 1935 1936 1937 1938 Average Kiirun 50 62 56 107 137 82.4 5.91 7.09 6.24 11.52 14.37 9.16 Taihoku 87 101 87 41 134 90.0 3.07 3.50 2.98 1.85 4.08 3.19 Shinchiku 2 1 - 4 9 3.2 0.37 0.18 - 0.70 1.56 0.58 Taichu T- 1 1 10 12 4.8 _ 0.14 0.13 1.30 1.51 0.94 Shoka 4 2 1 ? - 1.8 0.78 0.37 0.18 ? _ 0.33 Kagi 9 1 2 15 23 10.0 1.28 0.14 0.26 1.87 2.67 1.29 Tainan 3 1 7 20 - 6.2 0.27 0.08 0.60 0.16 _ 0.53 Takao 9' 6 14 22 34 17.0 1.10 0.69 1.49 2.17 3.09 1.80 Heito 5 1 - 1 3 2.0 1.20 0.22 - 0.20 0.59 0.43 Note: The data for Kiirun includes only bacillary dysentery, while those of other cities inclucfespart of the amoebic dysentery cases. In the city of Kiirun there was a marked increase in the reported dysen- tery cases in recent years, especially bacillary dysentery. This upward trend is clearly shown in Table IX. The types of the bacillary dysentery and their prevalence in Kiirun are given in Table X. In Kiirun 35 strains were isolated in September to November 1939 by Kurimoto and 18 strains agreed with Komagome B, one (1) with Nakamura type (Ishiama, 1941). Tomoishi (1933) reported that over 70 cases of dysentery in children were treated in Kagi Hospital from November 1932 to October 1933. It was proven that 34 cases were amoebic dysentery and 30 cases were bacillary dysentery. Of the latter according to Minota's classification the following types were determined: Type II 59.1% Type IV 13.6% Type V 9.1% Nakamura Type 4.6% Paradysentery Type A (Ohara- Minota Type) 13.6% In Pescadores 74 cases of bacillary dysentery and ten (10) cases of amoebic dysentery were reported from 1933 to 1937 with their annual distribution as follows (Watanabe, 1938): 1933 1934 1935 1936 1937 Total Bacillary Dysentery 8 23 6 17 20 74 Amoebic Dysentery 3 4 1 - 2 10 TABLE IX Cases of Dysentery in Kiirun from 1920 to 1938 (Kojima et al, 1940) Year Bacillary- Dysentery Amoebic Dysentery 1920 0 10 1921 0 15 1922 0 11 1923 0 3 1924 1 3 1925 0 12 1926 6 10 1927 5 14 1928 11 3 1929 14 5 1930 17 4 1931 42 5 1932 44 3 1933 55(4) 3 1934 50(3) 4 1935 62(4) 4 1936 56(4) 4 1937 107(13) 0 1938 137(33) 2 Note: 1. The data before 1930 were based on Endo’s report. 2. The figures in parentheses indicate the cases based on the examination of the dead bodies. According to Miyagawa and Endo (1933) the mortality rate of dysentery in Taihoku City and Kiirun was 13.3 percent for bacillary dysentery and 4.66 percent for amoebic dysentery. Sasaki (1937) reported 26 cases of pseudocholera infantum occurring in central Formosa within two years (1935-1936). Twenty-three (23) cases were Japanese and three (3) were Formosans; 18 were boys and eight (8) were girls. Eight (8) cases were reported from Kagi, in 1935. TABLE £ Bacillary Types and Their Prevalence in Kiirun from January 1935 to the End of 1938 (Kojima et al, 1940) Types Number Strains Examined Number Cases Examined Percent Komagome Type B 232 213 52.72 Schmitz Type 40 39 9.65 Kawase Type II 38 38 9.41 Komagome Type AI 31 31 7.67 Komagome Type B2 27 26 6.43 Komagome Type B3 19 18 4.46 Kawase Type III 14 14 3.74 Ohara Type 8 8 1.98 Kawase Type I 4 4 0.99 Komagome Type All 4 4 0.99 Komagome Type Bx 6 6 1.49 Unknown 3 3 0.74 Total 426 404 Cholera. There were two cases and one death reported from Takao Prefecture in 1940 (Taiwan Sotokufuho, 1940); the fatal case occurr'ed in February and the other case in March. Intestinal Protozoan Infections. There has not been much work done on the prevalence of intestinal protozoa in the southern part of Formosa. K5 (1941) made fecal examinations of 1,287 persons who had the habit of eating betel nut in Toko-gun of Takao Prefecture. His results are recorded in Table XI. Narihara and Ch5 (1941) examined the feces of 503 students (95 Japanese and 408 Formosans) of Takao Prefectural Tento Agriculture School and found 19.85 percent to be parasitized with protozoa. Of these 10.73 per- cent were by Endolimax nana which was most common. Endamoeba coli, Enda moeba histolytica. Giardia lamblia and lodamoeba butschlii were in order the next most common. No. Examin- ed Total Positive Total Negative Enda- moeba histoly- tica Enda- moeba coli loda- moeba Endo- limax nana Dienta- moeba Tricho- monas hominis Chilo- mastix mesnili Giardia lamblia Per- Per- Per- Per- Per- Per- Per- Per- Per- Per- No. cent No. cent No. cent No. cent No. cent No.cent No. cent No. cent No. cent No. cent Male 527 148 28.09 379 71.91 30 56.9 38 7.21 11 2.08 44 8.34 2 0.38 2 0.38 2 0.38 19 3.60 Female 760 284 37.36 476 62.63 49 6.44 63 8.28 13 1.71 88 11.57 8 1.05 11 1.44 8 1.05 34 4.47 Total 1,287 432 855 79 101 24 132 10 13 10 53 Fecal Examination of Residents of Toko-gun Who Habitually Eat Betel Nut TABLE XI 15 THE ACUTE RESPIRATORY DISEASES AND TUBERCULOSIS (Chapter VIII) There were 31,418 deaths of acute respiratory diseases reported in For- mosa in 1935; 5,145 were from bronchitis, 22,141 from pneumonia and 1,653 from pleuritis (Tomuku Tokei, 1937). Pneumonia. According to Oda (1937), in the cities of over 100,000 popu- lation in Japan the incidence of pneumonia is 1.33-2.63 per 1,000, while in the seven (7) large cities of Formosa it is 0.61-1.49 for the Japanese and 2.57-5.50 for the Formosans. Cho and Shu (1940) reported that 232 cases of lobar pneu- monia were admitted to the Medical College of the Taihoku Imperial University from 1931 to 1938, with the highest number of 57 in 1934 and lowest 12 in 1931. The age distribution and seasonal prevalence of the incidence and deaths are given in Tables XII and XIII. TABLE XII The Distribution of the and Deaths of Lobar Pneumonia in Taihoku According to Age Age Below 6 6-10 11-20 21-30 31-40 41-50 51-60 61-70 Above 70 Total Number of Cases 29 16 36 53 38 32 17 9 2 232 Percent of Total Cases 12.5 6.9 15.5 22.8 16.4 13.8 7.3 3.9 0.9 Number of Deaths 9 2 6 10 8 7 6 3 2 53 Case Fatal- ity Rate 31.0 12.5 16.7 18.9 21.1 21.9 35.3 33.3 100.0 22.8 Rin (1936) reported that in a period of five (5) years from January 1931 to December 1935 there were 432 cases of infantile pneumonia in Takao Prefecture Of these cases 133 were lobar pneumonia, 226 were catarrhal pneumonia, 21 were pneumonia of unknown type, 37 were pleuropneumonia and five (5) cases were accompanied by typhoid fever. Lobar pneumonia had its highest incidence in March, next highest in April and May and lowest in August and September. Catarrhal pneumonia was most common in June, May and July and least common in October,, November, and December according to the order listed. The mor- tality rate of lobar pneumonia was 15 percent and that of catarrhal pneumonia was 24.5.percent. TABLE XIII The Seasonal Distribution of the Cases and Deaths of Lobar Pneumonia in Taihoku Cases Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. Total No. of Cases 25 32 42 31 22 23 5 9 9 8 12 14 232 Percent of Total Cases 10.8 13.8 18.1 13.4 9.5 9.9 2.1 3.9 3.9 3.5 5.2 6.0 No. of Deaths 1 9 7 9 3 5 2 5 1 5 3 3 53 Case Fatality Rate 4.0 28.1 16.7 29.0 13.6 21.7 40.0 55.6 11.1 62.5 25.0 21.4 22.8 Tuberculosis. There were 8,416 deaths from tuberculosis in Formosa in 1935 (Tomuku Tokei, 1937). The Government-General of Formosa reported (Taiwan Jijo, 1939) that the annual number of tuberculosis cases reaches about 80,000*90,000 with over 8,000 deaths. The facilities for the tuberculosis patients are the Taiwan Government Matsuyama Clinic (capacity 150 in 1939), tuberculosis ward of the For- mosa Red Cross Branch Hospital, and the isolated wards of other hospitals. In 1939 it had been planned to establish a prefectural tuberculosis clinic in Taihoku prefec- ture and another in Tainan prefecture. According to Soda (1934) the death rate of tuberculosis in Formosa, as compared with that in Japan, was lower among the young but much higher among the old people, and in Formosa the death rate was higher among the old in the southern part than in the northern part. The reason for this is not known. Oda et al (l936) made studies on the tuberculin reaction of the inhabitants of Formosa and the results may be summarized as follows: The positive reactions to tuberculin among the public school children in Formosa is about 30-40 percent (as in Kiirun, Taihoku, Taichu, Kagi, and Tainan). Three hundred and eight (308) of the college students were tested with a.positive rate as follows: 70.3 percent among the Japanese and 78.9 percent among the Formosans. Of the 328 factory workers tested 89.1 percent of the Japanese and 96.0 percent of the Formosans showed a positive reaction. Among the 732 middle school children the positive rate increased from 38.0 percent to 50.7 percent for the Japanese and from 48.4 percent to 65,6 per- cent for the Formosans within a period of one and a half years. In Tainan Prison 1,143 persons were tested and 93.97 percent had positive reaction to tuberculin. The authors also reported that from November 1934 to October 1936 there were 447 Japanese and 266 Formosan cases treated in the Department of Internal Medicine, Taihoku Hospital; these groups making up 6.8 percent and 6.2 percent of the total out-patients respectively. 17 ACUTE INFECTIOUS DISEASES (Chapter DO Diphtheria. The official report of the Government-General of Formosa (Taiwan Sotokufuho, 1940-1941) shows that there were 1,394 cases of diphtheria in 1940; 847 cases and 130 deaths through July in 1941. The seasonal and prefectural distribution of the disease for the year, May 1940 to April 1941, is given in Table XIV. TABLE XIV Prefectural Distribution of the Cases of Diphtheria from May 1940 to April 1941 in Formosa Taihoku Shlnchiku Taichu Tainan Takao Taito Karenko B5ko Total 1940 May 16 6 8 15 15 1 1 62 June 13 4 23 14 10 3 3 - 70 July 23 5 16 23 15 3 8 1 94 Aug. 70 13 15 8 10 - 5 1 122 Sep. 58 29 21 32 8 - 4 3 155 Oct. 60 29 28 26 12 1 4 2 162 Nov. 82 38 30 20 18 2 5 3 198 Dec. 62 30 25 31 32 1 11 1 193 1941 Jan. 70 23 26 22 25 2 4 1 173 Feb. 27 18 14 24 26 1 2 - 112 Mar. 39 7 8 19 14 2 5 1 95 Apr. 18 2 11 30 23 3 5 - 92 Total 538 204 225 264 208 19 57 13 1528 Asahi and Aida (1938) in their epidemiological observations of diphtheria epidemics in Taidm City, give the figures of the incidence and deaths of this disease in the principal cities of Formosa for a period of five (5) years (Table XV). TABLE XV Incidence and Deaths of Diphtheria in the Principal Cities of Formosa (1932-1936) Place 1932 1933 1934 1935 1936 Cases 41 45 58 51 53 Taichu Deaths 2 1 3 0 3 Case Fatality 4.8 2.2 5.1 - 5.6 Cases 244 206 297 253 311 Taihoku Deaths 33 12 29 30 39 Case Fatality 13.5 5.8 9.7 11.9 12.5 Cases 30 29 49 64 43 Tainan Deaths 1 3 5 4 2 Case Fatality 3.3 10.3 11.1 6.2 4.6 Cases 26 40 23 20 31 Kiirun Deaths 2 3 2 2 3 Case Fatality 7.6 7.5 8.6 10.0 6.4 Cases 5 7 13 7 23 Takao Deaths 0 4 2 3 3 Case Fatality - 57.1 15.3 42.8 13.6 Cases 4 10 4 16 6 Kagi Deaths 1 1 2 2 0 Case Fatality 25.0 10.0 50.0 12.5 - Cases 20 46 56 22 20 Shinchiku Deaths 4 5 8 3 2 Case Fatality 20.0 10.8 14.2 13.6 10.0 Cases 2 2 6 4 2 Shoka Deaths 0 1 0 0 0 Case Fatality - 50.0 • — - - Cases 6 8 6 14 14 Heito Deaths 1 0 5 3 3 Case Fatality 16.6 - 83.3 21.4 21.4 Cerebrospinal Meningitis. Epidemic cerebrospinal meningitis y/as intro- duced to the southern coastal region of Formosa in 1903-1904. It has occurred sporadically in different places since that time. In 1934 there were 155 cases in northern Formosa and in 19/39 there were 342 cases in Tainan Prefecture. In Taiwan Sotokufuho (1940-1941) 634 cases of epidemic cerebrospinal meningitis were reported in 1940 in Formosa and 210 cases and 77 deaths in the first seven (7) months of 1941. The prefectural distribution from May 1940 through April 1941 is given in Table XVI. TABLE XVI Prefecture! Distribution of Cerebrospinal Meningitis in Formosa from May 1940 through April 1941 Taihoku Shlnchiku Taichu Tainan Takao Tariff Karenko Boko Total 1940 May 6 1 4 7 10 7' 2 37 June 2 - 2 2 2 1 2 1 12 July 2 - 1 5 3 3 - - 14 Aug. 2 - 1 3 6 - - - 12 Sep,. 2 - 1 3 4 1 1 - 12 Oct. 2 - - 2 3 1 1 - 9 Nov. 2 - - - 1 4 - - 7 Dec. 2 1 1 4 3 3 5 - 17 1941 Jan. 3 1 3 3 26 7 4 47 Feb. 8 - 4 3 27 22 5 - 69 Mar. 3 - 1 4 9 12 4 33 Apr. 4 1 4 2 7 1 2 - 22 Total 38 4 22 38 101 62 26 1 291 Noda and Sugita (1941) made an epidemiological investigation of the disease in For- mosa, based on the records of 20 years from 1919 to 1938. They found that both morbidity and mortality of the disease are higher in Formosa than in Japan. In Japan the number of cases per 100,000 population in the same period was 1.23 while in Formosa it was 3.57, nearly three times as high. The mortality rate was 56.95 percent in Japan and it was 60.52 percent in Formosa. The distribution of the disease (cases per 100,000 population) in the different prefectures of Formosa was as follows: Taito-cho 28.99 Tainan-shu 4.89 Karenko-cho 9.97 Taihoku-shu 3.70 Taichu-shu 2.78 Takao-shu 2.52 Shinchiku-shu 1.57 Boko-cho 0.50 The rate per 100,000 for urban districts was 3.52 and that for rural districts was 3.68. The seasonal distribution of the disease in Formosa may be shown in the following order of frequency: March (34.54 percent), April (18.20 percent), February (1415 percent), January (7.14 percent), December (5.67 percent), May (5:64 percent), June, November, July, August, September and October. According to Kiribayashi et al (1941) there were 156 cases in Taichu Prefecture in a period of 14 years from 1926 to 1939, 61 cases in 1935, 20 cases in 1936 and 30 cases in 1939. There were 211 cases, 210 Formosans and one (1) male Japanese, which occurred in one outbreak in Taichu Prefecture during March and April 1940. This epidemic is summarized in TablesXVH and XVIII. TABLE XVII Cases of Cerebrospinal Meningitis According to Counties in Taichu Prefecture, 1940 Region County Jan Feb Mar Apr May Total Percent Taiko-gun 16 10 2 28 13.27 Coastal Shoko-gun - 19 33 2 - 54 25.59 Hokuto-gun 2 - 1 - 3 1.42 Hogen 2 1 7 6 1 17 8.05 Taiton - - 13 - - 13 6.16 Central Taichu-shi - - 4 - - 4 1-90 Shoka-shi - - 1 - - 1 0.47 Winr in-gun - - 31 7 - 38 18.01 Tosei-gun «. 1 1 0.47 Nanto-gun - - 10 1 - 11 5.21 Hilly Noko-gun - 1 2 1 - 4 1.90 Shinko-gun - - 2 2 - 4 1.90 Chikusan-gur^ - - 31 2 - 33 15.63 Total 4 21 150 33 3 211 Percent 1.89 9.55 71.09 15.63 1.42 TABLE XVIII Cerebrospinal Meningitis, Case Fatality in Taichu Prefecture, 1940 Region Recovered Number Percent Deaths Number Percent Total Number Percent Coastal 51 (60.00) 34 (40.00) 85 (40.28) Central 34 (46.58) 39 (53.42) 73 (84.59) Hilly 28 (25.83) 25 (47.17) 53 (25.11) Total 113 (53.55) 98 (46.45) 211 (100) 21 Yuge (1937) reported that tuberculous meningitis composes 50 percent of the other meningitides among the children in Formosa. Epidemic Encephalitis. Twenty-five (25) cases of epidemic encephalitis were officially reported (Taiwan Sotokufuho, 1940-1941) in 1940 in Formosa, and 30 cases with seven (7) deaths January through July, 1941. All the cases except one (1) occurred in the period June to October. The exceptional case occurred in January in Taichu Prefecture. The disease is most prevalent in Taihoku Pre- fecture. The following is the prefectural distribution of the 55 cases: Taihoku 39 Shinchiku 6 Taichu 7 Tainan 1 Takao 2 Tait5 0 Karenko 0 B5ko 0 Total 55 Kobayashi (1939) reported that in the epidemic area of Okayama Prefecture of Japan as high as 2.05 percent of Culex pipiens pallens and C. tritaeniorhvnchus carried the virus of the disease. However, there is no information regarding the transmission of this disease in Formosa. Smallpox. There was an explosive outbreak of smallpox in Tainan Prefecture in the spring of 1939 (Noda et al, 1939). There were 67 cases occurring from March 14 to April 15, 62 of the cases were in Jo-sansho, Shinka-gun. The locality of the other five (5) was not known. All the cases were Formosans, 34 males and 33 females. The virus was found to be introduced from the opposite coast. From January 1940 to July 1941 only three (3) cases of smallpox were officially reported in Formosa (Taiwan Sotokufuho, 1940-1941), two (2) cases from Taichu Prefecture, and one from Tainan Prefecture, occurring in May 1940. Data on smallpox vaccination in Formosa from 1934 to 1938 are shown in Table XIX. TABLE XIX Smallpox Vaccination in Formosa, 1934-1938 (Taiwan Jijo, 1939) Periodical Vaccination Temporary 1st Time 2nd Time Vaccination Percent Posi- Nega- Posi- Nega- Posi- Nega- Total Posi- Nega- Year tive tive tive tive tive tive Positive Negative Total tive tive 1934 190450 15408 68136 88998 11112 43353 269698 147759 417457 64.60 35.40 1935 203150 10456 88311 77868 628 _ 292089 88324 380413 76.78 23.22 1936 204708 8518 96783 65169 46 29 301537 73716 375253 80.36 19.64 1937 206080 10965 101086 58277 829 3563 307995 72805 380800 80.88 19.12 1938 210885 13188 107341 56275 4445 2484 322671 71947 394618 81.77 18.23 Scarlet Fever. There were 61 cases of scarlet fever in Formosa in 1940 and 21 cases in 1941 through July according to the Formosan official report (Taiwan Soto- kufuho, 1940-1941). The following table will illustrate its prefectural distribution in one (1) year. TABLE XX Prefectural Distribution of the Scarlet Fever Cases in Formosa (May 1940-April 1941) Taihoku Shinchiku Taichu Tainan Takao Taito Karenko Boko Total 1940 May 3 — 1 — •> 4 June 5 - - 1 - - - - 6 My 3 - - - - - - - 3 Aug. 2 - - 1 - - - - 3 Sep. 1 - - - - - - - 1 Oct. 7 - - 1 - - - - 8 Nov. 6 - - 2 1 - - - 9 Dec. 5 - - 1 - 1 - - 7 1941 Jan. 7 7 Feb. 4 - - - - - - - 4 Mar. - - 2 1 - - - - 3 Apr. 1 - - 1 - - - - 2 Total 44 - 2 8 2 1 - - 57 23 Measles. Cho (1937) reported an epidemic of measles in Taihoku from the end of 1935 to the summer of 1936. One hundred and forty one (141) cases (13.9 percent of the total in-patients) were admitted to the Taihoku Hospital. Two-thirds of the cases occurred in March, April and May. Two (2) cases of exanthema subitum (somewhat similar to rubella) were re- ported in 1931, three (3) cases in 1933 in Taichu Hospital, and one (1) case was re- ported in 1934 in Kagi Hospital (Hirotsu, 1937). Twenty-four (24) cases were reported in Taihoku Hospital during a period of three (3) years ending with 1937. This number consists of about 0.021 percent of the total number of child patients which was 11,527 Whooping Cough. There were 1,144 deaths of whooping cough and influenza in Formosa in 1935 as reported in Tomuku Tokei (1937), but no indication was given as to the number of cases for each disease. In the Pediatrics Department of Taihoku Hospital 520 in-patient cases and 1,886 out-patient cases of whooping cough were treated in 1930-1935. One hundred and fifty-four deaths among the in-patients were reported with a mortality rate of 22.5 percent among the Japanese and 35.9 percent among the Formosans. This disease is most prevalent in summer and least preva- lent in Autumn. Tetanus. Tetanus is quite common in Formosa. The incidence rate among the infants in Formosa is about 30 times as high as that in Japan but the incidence rate among the Japanese infants in Formosa is much lower, being about the same as that on Japan mainland. Tables XXI and XXII are from Nabuhara (1938-1939). TABLE XXI Incidence of Infantile Tetanus in Formosa, 1932-1936 1932 1933 "153? 1935 1936 Incidence Incidence Incidence Incidence Incidence (Rate (Rate (Rate (Rate (Rate per per per per per 1,000 1,000 1,000 1,000 1,000 live live live live live Cases births) Cases births)Cases births) Cases births) Cases births) Japanese 6 .77 5 .63 6 .77 6 ..75 10 1.26 Formosan 4851 23.67 4843 22.89 4947 22.57 4987 22.07 4924 21.96 24 TABLE XXII Infantile Tetanus in Formosa in 1936 According to Prefectures Incidence Incidence Rate per 1,000 Births Taihoku 640 17.74 Shinchiku 711 24.01 Taichu 1254 22.78 Tainan 1424 22.81 Takao 759 23.52 TaitS 16 6.76 Karenko 61 17.02 BSko 59 23.03 Total 4924 21.99 25 OTHER INFECTIOUS DISEASES (Chapter X) Leprosy. As it was stated in the manual, leprosy is quite prevalent in Formosa. Its greatest incidence seems to be in the coastal regions. Tables XXIH and XXIV show the incidence of the disease in July 1930 and November 1934 according to the Police Bureau of Formosa (Kamikawa et al, 1936): TABLE XXIII Cases of Leprosy According to Prefectures Prefecture July 1930 November 1934 Taihoku 456 148 Shinchiku 55 35 Taichu 81 36 Tainan 303 188 Takao 103 91 TaitS 19 7 Karenko 13 7 Boko 54 65 Total 1,084 577 TABLE XXIV Cases of Leprosy According to Counties in Taihoku Prefecture County July 1930 November 1934 Taihoku-shi 36 52 ShinjS-gun 19 26 Kaisan-gun 1 2 Tansui-gun 5 6 Shichisei-gun 16 1*5 Kiirun-gun 16 14 Bunson-gun 1 4 Giran-gun 13 8 Rat5-gun 18 18 Suo-gun 7 3 Total 132 148 26 Kamikawa and Rai (1937) made examinations for leprosy in four localities of two prefectures on the western coast of Formosa; viz., Takao and Tainan. Their results are given in Table XXV. TABLE XXV Leprosy in Takao and Tainan Place Number Examined Number Positive Percent Positive Shaj5sh5 2,513 19 0.67 Takao KikS 11,534 27 0.23 Total 14,047 IB 0.33 Sanjosho 6,365 13 0.20 Tainan Tainan Anhei 5,539 3 0.05 Total 11,904 16" 0.13 Grand total 25,951 62 0.24 A government leprosy clinic was established in 1930. This clinic had a capacity of 700 in 1939. A private leprosy clinic was established by an English physician in Tansui-gun (at Yarisho) Taihoku Prefecture with a capacity of 80. Yaws. According to Takahashi, Asai and Chin (1940) the incidence of yaws has shown a distinct decrease in recent years in TaitS District but a moderate increase in Takao Prefecture. Table XXVI gives the cases of both regions for a period of five (5) years (1935-1939). TABLE XXVI Incidence of Yaws in Takao Prefecture and Taito District in 1935-1939* Locality 1935 1936 1937 1938 1939 Total Airyonankei 86 64 64 82 44 340 Airyohokukei 11 11 9 9 0 40 Raishakei 150 166 200 150 230 896 Karusukei 16 12 4 4 0 36 Subonkei 71 31 18 39 20 179 Tokokei 25 25 24 25 25 124 Kokokei (Ko shun-gun) — 0 0 2 7 9 Total 359 309 319 311 326 1624 Taimarikei 30 0 7 4 6 47 Kanaronkei 3 3 3 4 16 29 Taichikukokei 2 1 2 0 0 5 Coast and along Shokei 22 31 35 35 38 161 Total 57 35 47 43 60 242 ♦According to the Divisions of Aboriginal Affairs of both local governments. Venereal Diseases. In Taiwan Jijo, compiled by the Government- General of Formosa, 1939, the result of examinations of prostitutes for venereal disease was given as follows: Prostitutes Number Examined Syphilis Chancroid Gonorrhea Percent Licensed 45,582 103 613 1,228 4.26 Unlicensed 1,042 47 51 231 31.57 Ri et al (1941) reported that 53,291 patients were treated in the Depart- ment of Skin and Venereal Diseases, Medical College, Taihoku Imperial University, from January 1921 to October 1940. Forty thousand six hundred (40,600) cases (76.185 percent) were skin diseases, 12,691 cases (23.815 per- cent) were venereal diseases and 1,786 cases were diseases of urinary organs. The following table shows the percentage of the different venereal diseases compared with that in Japan Proper (according to Ito). 28 TABLE XXVII Ratio of Various Venereal Diseases Number Cases Percent Percent in Japan Syphilis 6,122 48.2 35.5 Gonorrhea 4,771 37.6 55.5 Chancroid 1,143 9.0 9.0 Lymphogranuloma venereum 655 5.2 0.0 TABLE XXVIII General Incidence of Syphilis in Formosa (Nakagawa et al, 1938) Place Persons Examined Number Examined Percent Positive Bacteriological Lab., Taihoku Hospital Japanese 4,693 22.88 Bacteriological Lab., Taihoku Hospital Formosan 5,307 33.39 Sanitary Div. of Central Re- search Bureau Japanese 5,054 17.51 Sanitary Div. of Central Re - search Bureau Formosan 2,531 26.27 Prostitutes in Taihoku Japanese 446 41.47 Prostitutes in Taihoku Formosan 208 67.30 Out-patients of skin diseases in Taihoku Red Cross Hospital 44,650 11.14 In-patients of same Hospital Japanese 142 6.5 In-patients of same Hospital Formosan 190 8.6 Examinations for syphilis were also made by Nakagawa et al (1938) among the prisoners and the jinrikisha men in Formosa (Table XXIX). TABLE XXIX Results of the Examinations of Prisoners Prisoners Formosan Chinese Japanese Male Female Male Female Male Female No. examined 1699 76 96 1 136 1 No. positive 458 28 23 0 34 0 Percent positive 26.9 36.8 23.9 25.0 Average percent positive 27.3 23.7 24.8 R s suits of the Examina of Jinrikisha Men tions Jinrikisha Men Number Number Percent Examined Positive Positive Formosan 544 65 11.94 Chinese 720 58 8.05 Positive in Positive in Positive in Positive in Urethra and Urethra or Number Urethra Cervical Canal Cervical Canal Cervical Canal Negative Place Examined Number Percent Number Percent Number Percent Number Percent Number Percent Formosan 125 49 39.2 15 12.0 49 39.2 49 39.2 76 60.7 Korean 48 12 25.0 8 16.6 5 10.4 15 31.2 33 68.7 Japanese 148 43 29.0 17 11.4 8 5.4 62 35.1 96 64.8 Total 321 104 32.3 40 12.4 62 19.3 116 36.1 205 63.8 Watanabe (1937) made examinations for gonococcus in licensed prostitutes in Taihoku C?ty and recorded the data in Table XXX. Examinations for Gonococcus in Licensed Prostitutes in Taihoku City TABLE XXX Total Total Positive Negative Ascaris lumbri- coides Tricho- cephalus trichiu- rus Hook- worm Entero- bius vermi- cular is Tricho- strongy- lus orien- talis Meba- goni- mus yoko- gawai Clonor- chis sinen- sis Fascio- lopsis buski ex- amin- ed Per- Per- No. cent No. cent Per- No. cent Per- No. cent Per- No. cent Per- No. cent Per- No. cent Per- No. cent Per- No. cent Per- No. cent Male 527 506 96.01 21 3.99 506 96.01 493 93.72 322 61.10 9 1.70 0 0 7 1.32 3 0.58 1 0.18 Fe- male 760 742 97.63 18 2.37 742 97.63 676 88.94 450 59.21 24 3.15 1 0.13 8 1.05 1 0.1 0 0.0 Total 1,287 1,248 96.96 39 3.04 1,248 96.961,129 87.72 772 59.98 33 2.55 1 0.07 15 1.16 4 0.31 1 0.07 Feces of 1,287 persons with betel nut eating habits from Toko-gun of Takao Prefecture were examined by Ko (1941) (Table XXXI). 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(In Japanese with English summary) 35 Maruyama, Y., 1935. Health conditions of Yami race in Hotel Tobago. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 34 (11): 1962-1966. (In Japanese) Matsmnoto, T., 1937. Uber eine Typhusepidemic Infolge des Typhus in der Prafecture Karenko und die Erfolge der Verhutung Derselben. Taiwan Igakkai Zassi (J, Med. Assoc. Formosa) 36 (4): 853-862. (In Japanese With German summary) Miyabara, H., 1937. Malaria in Hotel Tobago. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (12): 2801-1802. (In Japanese) Miyagawa, F., and Endo, T., 1933. Statistical investigation of the dysentery epidemics in Taihoku and Kiirun. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 32 (12): 1815-1816. (In Japanese) Nabuhara, T., 1938-1939). Infantile tetanus in Taiwan. The Journal of the Public Health Association of Japan, 14 (5): 261-271; 15 (12): 707-710. (In Japanese) Nakagawa, K., Arizumi, S., and Watanabe, F., 1938. Syphilis in Formosa. III. Result of Wasserman reaction of the prisoners and jinrikisha men. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 37 (4): 764-771. (In Japanese with German summary) Narihara, N., and Cho, M., 1941. Results of the faecal examinations of the students of Takao Prefecture! Tento Agriculture School. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 40 (1): 145-146. (In Japanese) Noda, H., Sugita, K., 1941. Epidemiological investigations of the epidemic cerebrospinal meningitis in Formosa. Taiwan Igakkai Zassi (J, Med. Assoc. Formosa) 40 (1): 176-177. (In Japanese) Noda, H., Toyosumi, M., and Sugita, K., 1939. Observations on the recent explosion of smallpox in Tainan Prefecture. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 38 (12): 1780-1781. (In Japanese) Oda, T., 1937. Pneumonia in the tropical region. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (2): 482. (In Japanese) Oda, T., Matsusuke, M., Ko, K., Tokushige, T., andUto, N., 1936. Supplemental report on the studies of the tuberculous internal diseases in Formosa. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 35 (12): 2858-2859. (In Japanese) Omori., M., 1937. Anopheles in Hotel Tobago, Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (12): 2800-2801. (In Japanese) Ri, C., 1937. Mortality rate of typhoid fever in the current year. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (1): 211. (In Japanese) 36 Ri, J., Rin, M., Rirl, K., and Ko, E., 1941. Patients admitted to the Department of the Skin and Venereal Diseases of the Medical College of Taihoku Uni- versity in the last 20 years. Taiwan Igakkai Zassi (J. Med, Assoc. For- mosa) 40 (1): 182-183. (In Japanese) Rin, K., 1936. Clinic and statistical observations of the infantile pneumonia in Takao Prefecture. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 35 (5); 1219. (In Japanese) Sasaki, K., 1937. Observations of Pseudocholera infantum in the central region of Formosa. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (10): 2263-2271. (In Japanese with German summary) Shimada, I., 1936. Dysentery among the children in Taihoku District. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 35 (12): 2864-2865. (In Japanese) Shimata, I., 1937. Seasonal prevalence of the acute infectious diseases among the children in Northern Formosa. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (8): 1891-1905. (In Japanese with German summary) Shimokawa, H., and Gabe, M., 1940. Klinische Seite des Zweiwochen-Fiebers (Febris exanthematica sporadica) in Formosa. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 39 (6): 770-779. So, K., 1935. Statistical observations of typhoid among children. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 34 (5): 671. (In Japanese) Soda, N., 1934. The peculiarity of tuberculosis in Formosa. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 33 (8): 1236-1237, (hi Japanese) Soda, T., Sagita, K., Abe, S., and Tsuchimochi, K., 1937. On Salmonella bacilli discovered from post mortem examinations in Taihoku and the epidemio- logical examinations. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (3): 641-669. (In Japanese with English summary) Sugatani, S., 1933. Clinical and bacteriological studies of diphtheria in the last 10 years. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 32 (12): 1819. (In Japanese) Tanaka, S., 1937. Investigations and clinical observations on microfilaria among Formosan Chinese in Boko Island. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (8): 1815-1825. (In Japanese with English summary) Tomoishi, K., 1933. Statistical observations of infantile dysentery in Kagi. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 32 (12): 1779. (In Japanese) Uchida, C., and Norikane, S., 1936. The pathology of dermatitis caused by “Iranoki” (Laportea pterostidua Wedd.). the indigenous plant of For- mosa. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 35 (9): 1958- 1964. (In Japanese with English summary) Uesaka, N., 1933. Statistical observations of the tuberculosis and syphilis in the Otonasopharyngeal Department in the last 10 years. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 32 (12): 1818. (In Japanese) Wake, I., 1938. Four cases of epidemic encephalitis occurred in Taihoku in the summer of 1938. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 37 (10): 1630-1646. (In Japanese) Wake, I., and Matsukuma, K., 1938. Pathological studies of epidemic encepha litis in Formosa. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 37 (12): 1991-1993. On Japanese) Watanabe, F., 1937. Examination for D. gonococci in licensed prostitutes in Taihoku City. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (12): 2638-2644. (In Japanese with English summary) Watanabe, Y., 1938. Distribution of typhoid fever in the Pescadores seen according to Shimojo's bacterial classification. Journal of the Public Health Assoc, of Japan, 14 (11): 605-619. (In Japanese) Yuge, G., 1937. Statistical observations of tuberculous meningitis. Taiwan Igakkai Zassi (J. Med. Assoc. Formosa) 36 (1): 212-213. (In Japanese) REPORTS Domei Jiji Nenkan (Domei Current Events Year Book), 1943. Taiwan Jijo (Conditions in Formosa), 1939. Taiwan Sotokufuho (Taiwan Gazette) Nos. 62-78, 1940-1941. Takumu Tokei (Statistics of Overseas Affairs), 1937. APPENDIX POISONOUS PLANTS Uchida and Norikane (1936) reported Laportea pterostidua Wedd., an in- digenous plant of Formosa, as causing a peculiar dermatitis in Formosa. The plant belongs to the Family Urticacea and is known only from Formosa. It is a wild plant, commonly found along streams and at the foot of mountains in the southern part of the island and also in the mountains in Karenko District. Besides this species there are two other wild species of Laportea: L. sub glabra Hay in Koshun region and L. kotoensis Hay in Botel Tobago. The leaves of this plant are covered with stinging hairs. The poisonous substance in the hairs, according to the authors is formic acid. The dermatitis caused by this plant is due to the mechanical irritation and chemical content of these hairs. The cutaneous inflammation is of a serous nature and is accompanied by infiltration, swelling, itching and pain. In severe cases vesicles may be formed. The chief characteristic of this inflammation is the peculiar pain which is likened to prickling with needles. The progress of the inflammation varies with different cases. In mild cases it lasts two to four days but in severe cases a longer period will be required for recovery. Ito (1923) reported the following poisonous plants from Formosa: 1. Solarium nigrum L. 2. Solanum lyratum Thumb 3. Capsicum anomalum Fr. & Sav. 4. Datura alba Nees 5. Ipomaea palmata Forst 6. Nerium odorum Soiand 7. Thevetia neriifolia Juss 8. Gerber a odoilam Gaertn. 9. Buddieia asiatica Lour. 10. Plumbago zeyianica L. 11. Pieris taivanensis Hay 12. Schima noronhae Reinw. 13. Semicarpus vernicifera Hay & Kawa 14. Coriaria intermedia Matsum. 15. Coriaria summicola Hay 16. Mallotus philippinensis Mueli. Arg. 17. Croton tiglium L. 18. Euphorbia tirucalli L. 19. Euphorbia neriifolia L. 20. Zanthoxylum pirtaciiflorum Hay 21. Abrus precatorius L. 22 Millettia pachycaroa Benth 23. Canavelia obtusifolia De. 24. Illicium anisatum L. 25. Ranunculus japonicus Langsd. 26. Ranunculus acris L. 27. Phytolacca acinosa Roxb. 28. Urtica thunbergiana S. et. Z. 29. Laportea pterostigma Wedd. 30. Dianella nemorosa Lam. 31. Veratrum nigrum L. var. japonica Bak. 32. Alocasia macrorrhiza Schott. 33. Arisaema ringens Schott. 34. Zantedetehia aethiopica Spr.