LOUSE POWDER STUDIES IN NORTH AFRICA ($943) by F. L. Soper, W. A. Davis, F. S. Markuam, L, A. Ri#HL and Paul Buck INTRODUCTION Severe and extensive outbreaks of typhus fever occurred in both Algiers and Morocco during the winters of 1941-1942 and 1942-1943. A survey visit to this area by Mr. Richard ALLEN of the American Red Cross, and Dr. George K. StropxE of the International Health Division of the Rockefeller Foundation in January 1943 led to negotiations with Dr. Edmund Sercentr, Director of the Pasteur Institute of Algiers, with Dr. GRENOILLEAU, Director of Health for Algeria, ard Dr. Gaup, Director of Health for Morocco,. for colla- boration in studying methods of typhus control, based on the use of insecticidal powders. The American Red Cross sponsored the studies which were undertaken with the approval of the State Department. The Rockefeller Foundation Health Commission assigned Doctors Fred L. Soper, William A. Davis, Floyd S. MarxHam and Louis A. Rieu, to the project. Through transportation facilities provided by the War Department an the Surgeon General’s Office this group came to North Africa late in June 1943 and established contact with the Pasteur Institute of Algiers, the Health Department of Algeria and the Medical Section of NATOUSA. Plans were made for the initial testing of materials and methods in collaboration with the Pasteur Institute of Algiers. Demonstra- tions of epidemic control measures were planned in both Morocco and Algeria, if epidemic typhus again became a serious problem during the ensuing winter season. The initial activities were devoted to: (1) evaluating the effecti- veness of different louse powders on natural infestations ; (2) study- ing locally available excipients for the preparation of louse powder; (3) testing the feasibility of mixing DDT powder in the field ; (4) determining the duration of effect of insecticides in the face of constant reinfestation ; (5) developing methods for the rapid 184 ¥. L. SOPER, W. A. DAVIS, F. 8. MARKHAM, L. A. RIEHL, P. BUCK application of powder to the individual ; and (6). developing admi- nistrative methods for rapidly and economically delousing com- munities for the purpose of blocking the spread of epidemic typhus. Considerable difficulty was encountered in securing adequate supplies, transportation and personnel for the field studies, and the program proceeded more slowly than had been anticipated. How- ever, during the following months the initial testing of materials and methods in a civilian prison was completed, and field demons- trations of delousing without the removal of the clothing had been made in Prisoner of War Camps and in the county of L’Arba, Algeria. The anticipated epidemic conditions required for field control demonstrations had not developed in North Africa when the rapid increase of typhus in Naples, Italy, led to a transfer of this part of the program to that city on December 8th, 1943, under the auspices of the Allied Military Government. This epidemic in a non-immune population, well seeded ‘with typhus at the beginning of winter, afforded an unexcelled opportunity for the rapid and dramatic demonstration of, the practical value of the method of delousing without removal of clothing developed in Algeria. The present report covers (1) intensive studies carried out at the Maison-Carrée Prison near Algiers on the relative efficacy of factory- prepared MYL powder and powders containing DDT prepared with local excipients and applied by various methods; (2) ‘the extensive field application of insecticide to the general population of the town and county of L’Arba in Algeria, and (3) a rapid field test in a Prisoner of War Camp, of the new factory prepared U. S. Army — 10% DDT pyrophyllite powder. The most important developments of the work in North, Africa were: (1) the demonstration, on naturally acquired infestations, that both MYL and DDT ‘are highly efficient pediculicides, (2) the development of the air-blown application of louse powder without removal of clothing from the body of the person being deloused ; (3) the demonstration that lousy people will take the trouble to come to’ accessible delousing stations to get relief ;' (4) the deve- lopment of administrative methods for the rapid disinsectization of both military and civilian populations. PERSONNEL ENGAGED IN STUDIES. In Algiers, Dr. Edmund Sereent, Director of the Pasteur Insti- tute, took a personal interest in the program from the beginning and assigned Dr. Béauer as the representative of the Pasteur Ins- titute to follow the scientific aspects of the. work. Dr. Paul Buck was assigned from the staff of the Pasteur Institute to work with the Foundation group in the actual application of insecticide and Arch, Institut Pasteur d’ Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 185 in ascertaining the degree of louse infestation before and after treatment. Col. W. S. Stone of the Medical Section of NATOUSA was kept informed of the plans of these studies and was of great assistance in making available needed materials with which to work. Col. Stone ‘was also instrumental in assigning a number of officers from Malaria Units to work in the field application of insecticide at L’Arba. Several of these officers later took an active part in the Naples campaign. Dr. SERGENT was responsible for making arrangements with M. le Directeur de la Sécurité Générale du Gouvernement Général for the studies at the Maison-Carrée Prison and with M. le Préfet du département d’Alger and the Président de la Délégation spéciale of L’Arba for the work in that county. All details of the work and the observations herewith reported are the direct responsibility of the Rockefeller Foundation Health Commission Typhus Team and Dr. Paul Buck. MATERIALS Insecticides Initial plans called for the study in North Africa of various newly synthesized insecticides in an attempt to develop a formula better than the MYL of the United States Army. By the time the work began in North Africa, however, the laboratory tests of the new insecticide, DDT, had proceeded far enough to warrant concentrating efforts on field studies of MYL and DDT preparations. MYL Insecticidal Powder of the U. S. Army. -- The MYL powder tested in the Maison-Carrée Prison was part of a shipment of powder manufactured by the McCormick Company of Baltimore which had arrived in Algeria in April 1943. This material was packed in 2 ounce shaker tins. The MYL powder used in the field at L’Arba was material ordered early in 1943 from the McCormick Company and packed in specially designed 2 ounce envelopes. The shipment arrived in Algeria in July of the same year. DDT (2,2-bis (p-chlorophenyl)-1,1,1-trichloroethane). — When the North African studies began there was available a small lot of 5 pounds of DDT wich had been received for field tests from Mr. Knipiine at the Orlando Laboratory of the U. S. Department of Agriculture. An additional 30 pounds of DDT was received later from the Medical Section NATOUSA, which also furnished the 10% DDT pyrophyllite powder used in the Prisoner of War camps. t, XXIII, n* 8, septembre 1946. 186 =F. L, SOPER, W. A. DAVIS, F, 8. MARKHAM, L. A. RIEHL, P. BUCK Cresylacetate-2,4. — 2,4 Dinitro Cresylacetate was tested in combination with DDT in a single experiment at Maison-Carrée. Hair Lotion. — The air lotion used at L’Arba was a modification of that described by Davis(:). An emulsion of the active ingre- dient, pheny! cellosolve, was made in water by the use of a ‘sodium alkyl sulphate, .Tergitol 07, at a concentration of 0.1 per cent. Since phenyl cellosolve and Tergitol 07 are miscible liquids, ¢ a stock emulsion may be prepared and used as required: : The emulsion was easily and simply prepared. Five per cent by volume of the stock solution of phenyl cellosolve and Tergitol 07 was placed in a container of convenient size, such as a. one-litre wine bottle. After the proper volume of water had. been. added and the bottle corked, the mixture was shaken vigorously before application. The suspension separates on standing for several hours but can be quickly re-established by shaking. Diluents for Insecticide (Barytes, barium sulphate, Ba,SO.). _ Barytes is mined at Maison-Carrée only a short ‘distance from..the prison where tests were carried out. Two samples of this material were received from the Cie « Produits barytiques Nord-africains >. The sample «Blanc Extra Fin» as found to be sticky but the « Extra Blanc» proved to be a suitable fine smooth white powder with little or no tendency to stickiness. It passed a 200 per inch mesh screen easily and had a pH of 6.8 but was very heavy, being over three times the weight of pyrophyllite used in the preparation of MYL. Cement Dust, — The Société Lafarge, at Point Pescade, a suburb of Algiers, furnished a finely ground limestone which is used. in the manufacture of cement. Chemical analysis showed this limestone to consist mostly of calcium carbonate with some magnesium car- bonate and oxides of silica, aluminium’ and iron. ‘This limestone powder was a dirty gray-brown in color, was gritty to the touch and had a pH of 9.0. It was, however, much lighter than the barytes, weighing approximately the same as does pyrophyllite. Preparation of Insecticides (1) Solvent Method. — Suitable quantities of DDT concentrate (100%) and the excipient were weighed out. The DDT concentrate was then completely dissolved in a volume of acetone sufficient to yield a workabiy wet paste when the solution was added ‘to the excipient. The resulting paste mixture was stirred thoroughly and continuously until the bulk of the acetone had evaporated leaving the active ingredient evenly distributed on the excipient. The (1) Davis, W, A. 1943, Journ. Am. Med. Assn ; Vol. 123, ‘p.. 825. ° Arch. Institut Pasteur d'Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 187 slight amount of acetone remaining evaporated when the mixture was spread in a thin layer on a paper-covered surface for final drying. (2) Mechanical Methods, — A, Hand Mixer : Weighed amounts of the active ingredients and excipients were placed in the baffle chamber of a small hand operated mixer and rotated for specified time intervals. The mixing chamber was fitted with baffleplates and excentrically placed on the surface of a revolving disc so that maximum distribution and mixing of the components could be obtained. When more than one sample was prepared for use in the same experiment the batches were mixed for equal periods of time. B. Bread Mixer: Two batches of 10% DDT powder were pre- pared in a bakery-type bread mixer. The machine consisted of a large cast iron tub which rotated freely in the horizontal axis and an eccentrically places set of mixing paddles which caused the tub to revolve slowly as the paddles moved through the contents of mixing chamber. From iime to time during the mixing period the paddle action was augmented by manual redistribution of the mate- rials in the tub. DDT concentrate becomes hard and lumpy on standing and must be milled shortly before mixing. Since the melting point of DDT is relatively low, the heat generated at the grinding surfaces of the mill produces a slight stickiness which prevents a smooth blend with the excipient in a bread mixer. This can be avoided if a certain amount of excipient be added to the DDT concentrate at the time of milling. Hot table. — When clothing is examined to determine the inci- dence and degree of lousiness, searching the seams becomes a labo- rious task, and any simple means of driving out the lice greatly facilitates their discovery. The louse has a limited adaptation to temperature, and a slight increase of heat causes it to move about and leave the seams. The louse generally crawls upwards and, even though negatively phototropic, will expose itself to light to escape heat applied beneath it. The heat applied must be moderate to avoid stupefaction or even death of the insect. , During the early work at the Maison-Carrée Prison it was found that effective use could be made of sunlight to heat a black metal surface which served as a «hot table» on which clothing was exa- mined. Lice present in the clothes emerged from the seams and crawled about the exposed surface of the garments. As the season advanced a kerosene stove was placed below the metal surface with fair results. Later, a cylindrical barrel frame with a superimposed rack for suspending clothing at an angle in the warm current of air rising in the barrel was placed around the kerosene stove. “This arrangement was not entirely satisfactory but proved useful in the final examination of clothing not obviously infested. t. XXII, n° 8, septembre 1945, 188 =F. L. SOPER, W. A. DAVIS, F. 8. MARKHAM, L. A. RIEHL, P. BUCK Applicators of Insecticide Shaker Tins. — Previous experience led to the use of a special type of shaker tin for the application of MYL, which is too moist ond sticky to sift well from the tin in which it is packed. The shaker tins used in North Africa were made by drilling one or two rows. of holes in the side wall about the base ofa cylindrical tin can having a diameter of three and one-half inches. With the perfora- tions in the side wall (not in the bottom of the tin) it is possible to keep the powder flowing continuously by rotating the tin slightly with each shake. Agricultural Dusters. — The agricultural dusters used were of two types (trade names, Toxine and Corona) both used by the wine growers in North Africa for the dusting of their vineyards. The Toxine duster is a bellows type knapsack duster in which the dust is picked up by an air stream directed downwards on the sur- face of the powder and carried out through an aperture placed near the top of the chamber. The Corona duster is a bellows type knapsack duster in which the powder drops from the hopper into a tube below. The air stream picks up the dust as it passes through the tube. Attempts were made to adapt the Hudson Rotary Powder: ‘Duster No. 608 for the application of MYL powder: to clothed individuals, but the physical properties of this powder as well as the mechanics) design of the duster rendered its use impractical. “ Hand Dusters ; Hudson, Cadet-Major, Plunger Type. — The powder chamber is immemiately in front of the compression chamber, ‘for- ming with it a continuous tube with an air valve located in center of partition separating the two chambers. The outlet aperture for dust consists of an axial tube, beginning about one-third of the length of the chamber from its distal end. Powder tends to pack around the outlet tube and discharge as «slugs». The axial inlet and. outlet tubes, together with its small capacity cause this duster to be relati- vely inefficient. However, it can be used in an emergency to good advantage, as was demonstrated later in the Naples epidemic. Dobbins « Superbuilt » No. 133. Plunger Type. — Air. passes from compression chamber through a.tube placed at the circumference of the powder chamber and enters the powder chamber at the distal:ent. Outlet consists of a series of apertures well back of the distal: end opening into a delivery tube placed diametrically opposite the inlet tube. When the duster is held so that the outlet tube is on the upper side, the air, en route from the inlet to the outlet, must pass upward through the powder carrying some of it into the air space of the powder chamber and thence out through the delivery outlet.’ This (together with the similar Hudson Admiral Duster: N*. 765) proved to be a highly satisfactory tool for applying louse powder.- Arch, Institut Pasteur @'Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 189 DeVilbiss Hand Power Sprayer Outfit and Modified Dust Guns. For use with portable power compressor units. — The DeVilbiss Sprayer outfit N°. TZ-601 is a hand operated unit consisting of a compressor to which is attached a spray gun fitted with a glass or metal container for liquids. The gun was modified to use positive rather than negative pressure, but was found to be unsatisfactory because of the continued demand for high pressure required for its operation. The modified De Vilbiss sprayer gun and several others built through the cooperation of the Surgeon’s Office NATOUSA and the U.S. Army Air Corps shops were used with varying degrees of success when attached to gasoline driven air compressor units. In general the limitations of this type of equipment are: (a) the ability of the compressor unit to maintain sufficient pressure to operate two or more guns continuously ; (b) the ability of the powder chamber to withstand the abrasive action of the excipient dust; (c) the faci- tity with which the powder chamber can be refilled and (d) the need for mechanically trained operators to care for the equipment. METHODS Determination of louse infestation The degree of louse infestation was determined with varying degrees of thoroughness. In work at the Maison-Carrée Prison the degree of lousiness of each individual’ was determined by removing all of the clothing and carefully examining the inner surfaces and seams for lice. In preliminary survey work, when an incomplete search revealed the presence of ten or more lice, the individual was registered at 10(‘) plus. In post-treatment examinations all garments were examined and complete counts made. The examinations were generally made in bright sunlight and negative garments were often subjected to hottable treatment to aid in the discovery in insects. The classification of post-treatment of lice as to stage of develop- ment was found to be very useful in evaluating the insecticide tested. Each insect was recorded as newly hatched, immature or adult. The post-treatment finding of only newly hatched lice indicates that the insecticide, although not ovicidal, has a persistent action which destroys the instars before they reach the nymphal or adult (1) Previous experience in community surveys had shown that popula- tions can be roughly divided into two groups ; those having not over 9 lice and those having 10 or more. Most of the persons falling in the first group will be found to have not more than 5 lice. t. XXIII, n* 8, septembre 1945. 190, L. SOPER, W. A. DAVIS, F. §. MARKHAM, L. A. RIEHL, P. BUCK SN stages. The finding of immature forms on treated garments is not necessarily an indication for repeated treatment. At L’Arba the subjects were not disrobed to determine the degree of louse infestation. A louse-index based on a rapid examination of the clothing about the collar and over the shoulders was considered sufficient for the purpose of this study. At Maison-Carrée Prison all examinations were carried out by members of the Rockefeller Foundation Typhus Team or Dr. Buck, with a few specially trained prisoners working under their direct supervision. Application of Powder Shaker Tin. — If bedding is to be treated the blankets are first spread out flat on the floor or table top and lightly dusted with powder from the shaker tin. The blanket-is then folded once-over. Next, the upper garments after having been turned inside-out are laid one by one in the center of the folded blanket and dusted indi- vidually. Particular care is taken to ensure thorough powdering of the neckband, and the seams about the shoulders, arms and waist. Coats, shirts and under-shirts are treated alike. The lower garments after being turned inside-out are treated in the same fashion. The side-seams of the trousers and the seams about the waistband, seat and crotch of both the trousers and underwear are heavily pow- dered. A certain amount of powder can be worked under the overlapping seams of the trousers by a brisk hack and forth bru- shing movement over the surface of the garment. The inside of the hat or cap is then powdered and added to the pile in the center of the blanket. Finally the corners of the blanket are folded over the dusted clothing so as to form a closed bundle which is given several smart blows at the sides and top in order to fluff the powder throughout the treated garments and blanket. If blankets are not being treated, the overcoat or waistcoat may be used as the covering of the bundle of clotifing in the final step. Mechanical Dust Pumps. — Essentially the same technique is employed in applying powder with both the hand operated and the powder-driven compressed air dust pumps. © The following paragraphs are quoted from the directions for powdering prepared 2 November, 1943: « Powdering Technique » «In using the duster, the operator should remember that powder should be distributed on the inner surfaces of the inner garments and on the skin itself. Those doing the work for the first time should: have the clothing removed from the first persons powdered to observe: the results obtained. If properly done, the entire inner garments should be more or Arch. Institut Pasteur d@ Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 191 less completely covered with powder and there should be visible powder on the body hairs of the chest, back, thighs, armpits and of the pubic and perineal regions. Since body lice are most often found in the seams of the clothes about the neck, armpits, waist, shirt-tail and crotch of the pants, these areas are particularly important ones to be powdered. « The dusting of individuals should follow a certain routine to avoid missing some parts of the clothing as must occur at times where each person is handled differently. The following routine has been found useful : 1. — Dust inside of hat and replace hat on head. 2. -— With arms extended at shoulder height at the sides (not in front of the body) insert delivery tube up first the right and then the left sleeve and pump powder in between the skin and the innermost garment. Powder should reach well into the armpit and the position of the gun should be shifted to get powder all about the shoulder. « In case the subject is wearing more than one layer of clothing, dust should be applied between his underwear and shirt as well as between the underwear and the skin. 3. — The delivery tube is next inserted at the back of the neck and a liberal charge of powder shot down the back, care being taken to dust the neckband itself. 4. — The tube is next inserted inside the clothing from in front and powder sprayed first on one side, then on the chest and lastly on the other side, special care being taken to again reach the armpits, 5. —- The tube is next inserted, after the trousers are loosened, inside the innermost garment and a good dose of powder delivered to the crotch and pubic area, With the tube still in contact with the skin, the under- clothing is powdered, special attention being paid to the waist and side seams. 6. — With the trousers still loose, the tube is inserted down the rear of the pants next the skin and powder is shot down over the buttocks and rear of the crotch, « Note: if more than one layer of clothing is being worn, steps 3, 4, 5 and 6 above are repeated for the second layer from the skin. » SECTION |: STUDIES aT THE MAISON-CARREE PRISON The Maison-Carrée Prison had, at the time of these studies, approximately 1,000 prisoners, accomodated in three wards, two for males, one for females. Only small demonstrations were attempted in the ward for females and no further reference will be made to the work there. The male prisoners, most of whom were Arabs, differed in prison status, clothing and living conditions. A considerable number of prisoners were employed as trusties in handling the others. These trusties received better food, cloth- ing and quarters than did the other prisoners. Special concessions were made also for mechanics, cooks and other specialized workers. Some prisoners, especially those serving short sentences, had friends or relatives with sufficient funds to supply them with extra food, soap and clothing. These were considerably better off than were prisoners depending entirely on prison issues. The latter were obviously under-nourished and had little or no soap for washing t. XXIII, n° 8, septembre 1945, 192 F, L, SOPER, W. A. DAVIS, F. S. MARKHAM, L. A. RIEHL, P. BUCK the trousers, jacket and blanket which comprised their entire wardrobe. The prison routine calls for the use of woolen clothing in winter and heavy cotton in summer. Due to the war and scarcity of mate- rials, summer clothing had not been issued to many of the priso- ners and numbers of them continued to wear winter woolens throughout the summer. The work of the prisoners at Maison-Carrée varied according to the length of sentence imposed. Thus the prisoners in Ward I were of two groups, those condemned for life and those confined for minor offenses. The minor offenders were hired out in gangs to do agricultural work outside the prison grounds, whereas the lifers worked in the open courtyard of the ward at relatively light labor weaving mats and baskets for which they received a small stipend. The lifers in Ward I had not been issued summer clothing whereas most of the short termers wore cottons. The majority of prisoners in Ward II had been, sentenced to forced labor. These men worked at hard physical labor preparing fiber for basket and mat weaving. This work was done under guards in a large room where the prisoners were crowded together on the floor. Prisoners in both Wards I and II were provided with fiber mats and blankets and slept in groups of 80 in large dormitories where they were confined from 5:30 in the afternoon until 7 AM. Because of the intimate contact and crowding, particularly in Ward II, the opportunity for a daily interchange of parasites was excellent. Under these conditions only the most industrious of the prisoners were able to keep themselves relatively free of lice. The steam sterilization plant at the prison was little used, because of shortage of fuel and mechanical breakdowns. The first visit to Maison-Carrée was made on 23 July with Dr. Béauet at which time arrangements were made with the Direc- tor of the prison for beginning work. Work began with a preli- minary pre-powdering louse survey, July 26 to 29. This survey (Table I, Groups 1, 2, 3, 4) revealed 153 lousy prisoners among 158 examined, 116 of whom had more than 10 lice each. Further surveys of unpowdered individuals were made from this time on through the end of October (Table I, Groups 4, 13, 14, 23 and 24) with the finding of even higher degrees of infestation. From these results it is clear that any reduction from the July level noted in the louse burden of test groups must be attributed to the insecticide used. The materials and methods used on 24 groups of prisoners at Maison-Carrée are outlined in Table II. Experiment I The initial test at Maison-Carrée was to compare the action of repeated doses of 5% DDT in barytes and of MYL on natural Arch. Institut Pasteur d'Algeérie. LOUSE POWDER STUDIES IN NORTH AFRICA 193 infestations in an environment where exposure to reinfestation from untreated persons could be almost entirely prevented. Ward I was chosen for the first test with observations in Ward IL to serve as a check against the possibility of a seasonal reduction of louse incidence being attributed to the use of insecticide. The prisoners were called by number and checked off as the clothing of each man was dusted by hand (shaker tins). TABLE I: LousE couNTs oN UNPOWDERED GROUPS aT MAISON-CARREE PRISON = Group | Namber} with | over 9 © oOver9| Per | Average Pate Ward Number oa Lice Lice Lice Cent Number | ined Lousy | of Lice 7/26-29 1 41, 2, 3 108 104 77 7 96 4 2 : 50 49 39 78 98 10 + 8/9 2 4 48 48 hh 92 160 40 + 8/29 2 13,14 20 20 20 400 100 10 + 9/8 2 13,44 20 20 47 85 100 10 + 9/13 i 13,44 20 20 20 100 100 10 + 9/20 a 13,44 20 19 46 84 95 39 9/27 2 13,44 47 47 16 | 88 400 38 9 30 2 23,24 20 20 48 90 400 37 10/8 2 23,24 49 49 47 36 100 72 10/15 2 23,24 48 48 47 % 100 157 10/22 7 2 - 23,24 18 18 16 89 100 02 10/29 2 23,24 418 48 5 83 100 90 The 108 men examined in Ward I (Groups 1, 2, 3) were divided into three groups of 36 men each, and hand dusted (shaker tins) as follows : af The clothing and blankets of the men in Group 1 were treated with 5% DDT in barytes (barium sulphate) and redusted with the same material 17 days later; those of the men in Group 2 were dusted twice at a 7 day interval, and those of Group 3 twice at a 14 day interval with MYL. All other inmates of Ward I were treated with MYL twice with an interval of 14 days to prevent them from grossly reinfesting the study groups. t. XXIII, n° 3, septembre 1945. F. L, SOPER, W. A. DAVIS, F. 8. MARKHAM, L. A. RIEHL, P. 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Institut Pasteur d’ Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 195 Insecticide MYL was applied also to the garments of all new pri- soners coming to Ward I and to those returning to the ward after a stay in the prison infirmary. So far as is known, the only prisoners in Ward I to escape the initial dusting were three who assisted the guards in the adminis- tration of the ward and 15 who worked in the bakery. These assistant guards were dusted three days and the bakers 13 days after the rest of the prisoners. This failure to dust all simultaneously is probably of little importance, since these 18 men all enjoyed spe- cial privileges, had separate quarters and were much cleaner than the common run of prisoners. The clothing and blankets of Groups 1, 2 and 3 were examined at intervals after both first and second treatments. In pre- treatment examinations, counts were discontinued on any given individual when 10 lice had been found, but post-treatment exami- nations covered the entire inner surface of all clothing worn and both sides of blankets. The first post-treatment counts on Groups 1, 2 and 3 showed that both DDT and MYL had been very effective in reducing the louse burden of the treated prisoners (Table If). The two to four day counts indicated that the immediate effect of DDT had been somewhat less than that of MYL, but the 7, 10 and 14 day counts definitely favored DDT. The DDT-treated group showed a steady decline in numbers of lice up to the 17th day; when it was retreated. The hatching of young had apparently ceased by the 10th or 11th day. In the MYL treated groups, 2 to 4 day counts were lower than 7 day counts and in the group not re-treated until the 14th day, there was a decline in the louse infestation between the 7th and 14th days with hatching of young forms practically nil between the 10th and 14th days. The striking reduction in adult forms in all three groups is most significant, since the egg laying function on which the species depends for continued exis- tance is a function of adult life. The second treatment of Group I with DDT seventeen days after the first, was followed by examinations at 7, 13, 25 and 39 days after this second treatment, with practically no lice being found. The tast examination of this group, made 67 days after the second treatment (83 days after the first treatment) showed that about a third of the group was again lightly infested. This infes- tation was so slight that the prisoners still considered themselves louse-free. Examinations of the MYL treated groups (2 and 3) failed in both cases to reveal the presence of an appreciable number of lice for some weeks, As was to be expected, evidence of reinfestation was found earlier, in groupe 2, retreated after 7 days, than in groupe 3, which was re-treated at an interval of 14 days. t. XXIII, n° 8, septembre 1945, F. L. SOPER, W. A. DAVIS, F. S. MARKHAM, L. A. RIEHL, P. BUCK 196 *syuno0o yeijsed o10m 19g A[DE UO ByUN0D TV » py ~ iv J] PIGAA Uy SaBTOSjad 10} ydmin — 2 N . J 919", Uy eyep oes noseas ames 94) 3ujsnp sasuosjid poyzazjuD oy SNOppPUCD ejquagduioD 10g ¥ _ aeysay — :7y (1) W 8 61 SE FO} 8s | 68h é W v8. &8 S8/0t oO J & 13 0 J 0 0 } 0€ 9S 82/6 0 V V 63 0 0 0 0 0 $8 ey WH6 0. 0 ¥ ee 0 0 9 0 0 es 08 2/6 0 0 0 e& } 1 0 0 & ee %% Lal8 o | o cl y weofs jr [+ | o | 9 ge Lk 03/8 pe7¥esj-02 dnowg peujmexg 20N - I+ lo Jo 0 | 9 se % L¥/8 payeesj-02 dnoig . $ ya | & & at 9§ 0 0 0 | 0 | 0 ¥€ 0 &} J 0 9 se ot £18 ro} je | sg z | « [es [so [x | ¢ | w | 2 Te [8 joo | o sy | se | co | one . paqeely-o1 dnoig I g ze 0 SI ¥€ 0 | é | Ww | ¥ | st | ¥E 8 L Sth g & 9£ v6 L-4/8 quemyeory TYV yat | Ste | 4¥ &% oe ¥e fb | We | 69 9% £€ 48 Wes | WL | 8S 92 98 96 8 a O8/L Vv N I +6 . v N I +6 . v N I +6 “sod ee | 8 sot Laas _-| eo] see oo eee | OO] - ante yueu “mexy aor “ON Nj oN aon “ON N x (M917 “ON as No | peer i" sivp pF 103J8 poreel}-0y skep 2 deqje pezees}-0y skep LZ] 10138 pajeeay-oy e10j30q od esidqdoada-TAW adqdordg-TAW soidaeg- Lad %/o g skvg € dnoay @ dnoig ¥ dnoig — —— _— aan _ — ¥ SdNOUD GALVAUL-AU NI SATAUNS ASNOI GALVadaY *‘NOSIUd AFHUVD-NOSIVAL : | LNAWIVAAXY — ‘[[[ ITAV | Arch. Institut Pasteur @’Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 197 In all three groups, negligible infestations were found at the end of 56 days after first treatment. The difference in the degree of infestation of groups 1 and 3, re-treated after 17 days and 14 days, and of group 2, retreated after only 7 days is probably significant. Discussion. — A study of the behaviour of the louse population on groups 1 and 3 before re-treatment suggests that for the maximum result with the minimum amount of insecticide, the period between treatments may well be longer than 17 and 14 days. Theoretically an insecticide which is fully effective immediately against all froms present except the ova but which has no delayed residual action should be repeated at about 14 days to catch the early post-treatment-hatched lice before them come into active egg laying. With the demonstration of continued activity of the insec- ticide this period may be lengthened accordingly. From the epidemiological standpoint, it should be emphasized that the post-treatment counts are complete. counts based on a thorough search in the seams of the clothing and an examination of blankets. The degree of lousiness found 83 days after treatment began was not such as to have permitted the rapid dissemination of typhus in the ward, had it been introduced. It seems reasonable to suggest on the basis of these counts that a population which has been thoroughly powdered twice may be considered safe from important outbreaks of typhus for at least a three month period. The results in Ward I suggest that the complete eradication of lice in an institution or even in a community may be feasible with the proper application of either MYL or DDT. Experiment Il Experiments II and JII carried out in Ward 2 were designed to test, under conditions favoring reinfestation, the action of single doses of 5% DDT, of 10% DDT, prepared in various ways and of factory prepared MYL, applied in various ways. An additional accidental variable was introduced in Experiment II through the failure of mechanical equipment used to apply the same amount of insecticide as was applied by hand. Whereas in Experiment I, the possibility of reinfestation was reduced to a minimum, reinfestation was favored in Experiments II and HI. Only the clothing of the prisoners in these experiments was powdered ; their infested blankets were ignored. The remaining prisoners of Ward 2, where conditions were more favorable to rein- festation than in Ward I, were not powdered. Intimate con- tact continued between treated and untreated individuals both day and night. In Experiment II eight groups of ten men each were treated with varying combinations of DDT, barytes and cement dust, some by hand shaker application, and others by agricultural mechanical t. XXIII, n° 8, septembre 1945. F, L. SOPER, W. A. DAVIS, F. S. MARKHAM, L. A. RIEHL, P. BUCK 198 60 8% ey or Va aT og f'OV 6S Ot 0's OT 6's 3's Os aayye shep 9g o'r sy 6°0 oT VT oy LY os os 63 VS oF BF ay 60 daze Shep 1% oF st 80 VT 0% Vy Gy 66 WL 60 ey 0 L's ad 20 qayye shep Fy 80 eo ey oF 80 fe” ge £3 "6 9% VT 670 3% 3% oF aaye skep 7 suid sud sad snid said snyd suid snd snd sad sad sold sad sod snd aaojeq Aepiy v N 1 Vv N I v No i Vv N I Vv N 1 ‘yape pue ydmAu ‘aeqysut ‘a8eys qovo Jo ao; Jo wequinu sseseay : g NOILOAS 6 G 6 0 L 8 q 9 9 J Z 8 9 6 6 aoqye skep QZ V 9 6 J 6 oF g 8 8 3 6 6 3 8 6 dae skep 1 ¥ 6 OF J oF OF S 8 8 y Sg oF & 8 1) 3 dayye sAep HF J g ov ¥ oT OF ¥ oF 0 J 6 OF & oF 0} aoqye shep f 8 OF OF 01 0 OF 6 or OF or or OF OF oF OF er0jéq Kep ¥ +6 sod xa +6 sod xq +6 80d xq +6 sod xq +6 sod xq *suolyeysezur AAvey Jo Jequinu puke TONeIsezU] JO TOMNQWISIG * Y NOLLOGS 6 8 L 9 g dN0u9d ‘20 g 20 QE ‘20 g “20 SY "20 9 yunouy dung puey pueyq puey dung uoneoyddy ]eormeqos yeoraeqoey; Teotaeqooy; quaajos qUsAOS THN soydaeg seydieg soydieg soy 41ey soydaeg yueniiq Lad °/oS Lad °%o ¢ Lad %og Lad %og Lad °%/o0¢ appryoesuy ‘GarlIddy LNOOWVY FHL GNY NOLLVOrIdd¥Y JO GOHLAN AHL ‘NOILVUVdaud JO GOHLEA AHL ‘INANTIG JO ADIOHD AHL ‘[Qq AO NOLLVYLNADNOD FHL ONIAMVA AO SLINSAY : [[ LNAWIYadxyY — ‘Al FTV Arch. Institut Pasteur d’Algérte. 499 LOUSE POWDER STUDIES IN NORTH AFRICA (panui]uo?) J] LNAWiuadxy — ‘AT ATavyE 6¢ 8°6E 8°01 OY | LL rae 61 80 9% VE oS WT or 6°0 dae skep gz ¥L oF 6 LI 6 a3 9°0 80 £0 8% LG VI 8} 8'T 80 qaqje shep 1% sayd soyd suid sod snjd | said 870 th £% sy a3 Ve 6) 6 63 Jaye shep yp said | sod suyd said snyd | suid ey 9% 2% re ae 6° 20 v0 9°€ Jaiye sdup 2 sad sud snd suid soja snid suid snjd sald snd sntd said soid sold snd eaojaq dep 5 Vv N I v N I Vv N I v N I v N I “sjupe pue qdadu ‘aeqysuy ‘o8eys Goes Jo ad}] Jo Jequinu aseseay *° q@ NOLLOUS 9 L L 6 04 ol } 9 8 & L 6 t 8 6 aayjye sfep gz A 8 8 6 oF oF 0 9 6 e oy oF J 4 6 doyye skep 7g OF oF OF OF OF oF 3 9 6 8 6 Ov g 8 oT Joye shep +f L OF 01 or 0 Or & 6 Or g or oF £ 9 or aaqje skep 2 OF oF oF OF oF OF 8 oF oF oT oF or OF oF OF asojeq Sep F +6 sog rq +6 0d XY +6 S0d xq +6 Sod xq +6 Sod xy | “suoiessejuy AAvaq JO JOqUINT PU UOWeIsazu! Jo TOYNqIIsIq : V NOILLOWS 4 &t oF VW oF dowd 20 OF ‘20 8 “Z0 LE .yUDOMLY 800N 800N puep dung poey uoneoyddy jeoraeyoayw yeolueqoeyy [ea eqoow V9 © oe 4 £0 oF “y ye Ve 09 or 6} o's OF 9778 siep 8z ve 16 0% 0% Vs 6°) 0 Ve L0 a8 rs "0 qaye skep FZ V3 es $70 Lt 6'e 0 rr er 9°0 VE Ze 10 soya ese 7 ev v4 re L0 oF ey £0 ct 9 gO os oy aoiye shep L 80 28 6's 60 £0 3 80 80 9¢ 60 Lk vg gaye shep ¢ eer 9°8T Tes Sat 8°S% OVE 6°) ow S'8t 9°St £'62 0°8t asojoq Avp F Vv N I Vv N I Vv N I Vv N 1 ‘y[npe pue qydurdu ‘seqsuy ‘gZeis yous JO aa}j JO sequinuU eseloay + g NOILOGS t L 8 3. oF oF 3 6 6 ¥ 8 6 Joe Shep 9% £ g 8 ¥ OF ot t L 6 £ L 6 10x38 Shep 1% } 9 6 ¥ L oF 0 L 6 5 9. oF aayje Shep FF z L 6 3S OT OF B 8 OF g 8 OF soye step £ 3 8 6 4 ¥ 8 or g 6 oO e 6 OF aoe siep ¥ OF oF OF of 0 ob 6 oF ot 6 OF Or aaojaq Aep + +6 sod xq +6 sod xg +6 sod or family dwelling places. Permanent Central Powdering Station. The name, age, sex and address of those coming to the permanent powdering station were recorded. Checking these lists presented Arch. Institut Pasteur d’Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 211 many difficultics but insofar as possible the individuals who came to the station were credited to the lotissements, douars or other sub- divisions where they resided. This detail was somewhat simplified after the introduction of numbered tickets. The station was kept open until 7 PM., every dey and the bulk of its patrons were older men, youths and children ; women seldom came. In addition to the central powdering station a certain amount of dusting was done in the markct-place on Wednesdays and Sundays, the local market days. Records of this work were kept and treated in the same manner as those at the central station. Institutional Delousing. Early in the L’Arba program arrangements were made with the local school authorities for the delousing of the school children in their class rooms. The effectiveness of the treatment would thus be demonstrated in homes throughout the community and it was hoped that this would facilitate the general acceptance of the program by the adults. With the assistance of the directors and teachers the work was carried out in both fhe boy’s and girl’s schools. The only differ- ence in handling of the two groups being the application of the hair lotion to the hair of the girls. Most of the boys were their hair very short and it was casier to treat them with powder than with lotion. Records were kept of the names and addresses ant the incidence of lousiness among the pupils. DISCUSSION OF RESULTS. During the course of the delousing project in L’Arba 9,376, or 66.8% of the 14,030 Arab inhabitants of the commune were pow- dered. There were 4,241, or 30.2%, dusted twice and 4,671, or 33.2%, were not treated. Tables VII and VIIT show the number of percent of first and second ircatments and the number of persons treated per man hour of labor. Table IX presents a comparaison of results in house-to-house con- tacts and the use of temporary powdering points. The breakdown of powdered individuals into sex and age groups is given in Tables X and XI. Personnel, — The primary problem of the L’Arba program was the shortage of female assistants to work with Arab women. It is impractical to attempt large scale delousing in the region relying only on professional personnel such as doctors and nurses to powder the Arab women. With the greatly inflated family incomes t. XXIII, n° 3, septembre 1945. 212, L, SOPER, W. A. DAVIS, F, S. MARKHAM, L. A. RIEHL, P. BUCK TABLE VII. — FIRST AND SECOND Persons not powdered Location Census eee Number Percent Lotissement Eglise.. ...... ese aaeerrisee oe 293 24 8.2 Lotissement Djipoulog,........... 06... cece ee 452 32 7.0 Lotissement Medjabri.... 6... kee eee 522 66 12.6 Lotissement El Fass........,.. nan 804 100 124 Lotissement Moll........0...-. eee eee aes 365 53 14.5 Lotissement Boulevard de France... ..... ..... 47t 69 14.8 Lotissement Due dAumale..................... 209 43 20.6 Lotissement Boulevard, Lamartine............... 101 22 21.8 Lotissement Rue Carnot......... 0 .........0000. 77 5 6.8 | . Lotissement Rue Blandan.... ..........-....4. 207 37 17.9 | TOTAL for Lotissements..,.......... 3.508 454 12,9 Ecole de Gargons..... 0.00.0... cece eee eee 407 7 4.7 Ecole Primaire de Filles.... .... see ee nee ee 234 4 17 Civil Prison..... co. eee eee eee ties 20 0 0 Powdering Station .-....... 0.00. ..e ccc eee eeee GRAND TOFAL.......... eee 4.462 462 41.4 a Census made by delousing personnel as part of the work of the delousing program. Arch Institut Pasteur d’Algérte LOLSE POWDER STUDIES IN NORTH AFRICA 213 TREATMENTS IN L’ARBA VILLAGE. Persons Persons Total Total Persons powdered powdered twice treated number number ~~ a ree per man Number Percent Number Percent treatments J man hours hour 269 91.8 198 67.6 467 88 5.3 420 93.0 286 63.3 796 112 6.3 456 87.4 340 65.4 796 95 8.3 706 87.6 424 52.7 4.128 176 6.4 312 85.5 fos 41.9 465 86 5.4 402 85.4 224 47.6 626 88 7A 166 79.4 69 33.0 235 32 7.3 79 78.2 30 29.7 409 6 18.4 72 93.6 33 42.8 105 10 10.5 170 81.4 7h 35.7 264 14 47.4 | 3.050 8&7 1 1.834 52.3 4.881 707 6.9 400 98.3 353 86.7 733 74 10.2 | 230 98.3 449 63.7 379 a 9.2 20 100 18 400* 33 4 8.3 41a** 413 ** 88 4.8 3.700 88 9 2 346 06.4 6.046 Ons 6.6 * (ther prisoners had heen released during interval between treatments. ** Treated at L'Arba powdering station, but assigned and counted in individual lotissements. t. XXIII, n° $, septembre 1945. 214 ¥F. L. SOPER, W. A. DAVIS, F. S. MARKHAM, L. A. RIEHL, P. BUCK f TABLE VIII. — FIRST AND SECOND ~ TNA Persens not powdered Location _ Census ee Number Percent Douar Tenout.......... cece eee cee cere e ene 166 * 0 0 Douar Sakamody 450 ** 0 0 Douar Zerbout........ ... eee 1.186 ** 306 25.8 Douar Bousequine............6 66 cece eee eee 1.435 ** 495 34.5 Douar Sohane...... 0... 0 cece cece eee cee eees 1.287 ** 79 64.5 Douar Khodja and Bakir.............. sceeeeeee 3.195 ** 2 540 80.5 Powdering Station.......... cesses cece e eee TOTAL for Douars..............05.6 7.649 4.110 53 7 Mohieddine District.............-.00e cee uc neers eee Bohane District.......... cree nee Powdering Station Farm Sainte Angéle 55 * 0 0 Farm El Taous, 126 * 25 19.8 Farm Grandou...... .... 138 * 0 0 Farm Ben Assen 979 * Bh 8.6 Farm Coaderc......... 2. cece eee eee ee eee 5* 0 0 Farm Claret...... 2 ..e cece eee cee eee ees 37° 0 0 Farm Tordjmann 97 * 0 0 Farm Vallot 31° 0 0 Farm Vidal............ .eeeee eee Q5 * 0 0 Farm Bouchtop.............2..s.005- 35° 0 0 Farm Belgodene...............00:cce ees eeeeetee 26* 0 0 Farm El Euldj......... 00... cece cece eee tees 38* 0 0 Farm Valero, ........ 26. cece cee ecto ee eee 127 0 0 Farm Saint Philippe 61° 0 0 Farm Lagae.............. 13* a 0 Farm Ben Nouar e! Louz........ ..-.. .0.- sees 166 * 0 0 Farm Mohieddine. ...... ...cese eee cee cree B84 * 0 0 Farm Kadem............0 cece cece eee teens ot 4 3.7 EH} Farm Mokhfi......... 00... cee cece eee eee 906 * 0 0 Farm Sarraoui....... 2. .e ccc ce cee cece ees 31° 0 0 Farm Cherabas... 20.0... cece e cece cere en cee 153 * 0 0 Farm Cheragas........ seen cence eee cece eens 55 * 0 0 Farm Rachdi..........-.. 0... cece cece eee cree 55° 0 0 Farm Bealaoudi.... ....... 60-202 ce cee eee 69° 0 0 Powdering Station ...........6. casce ceae eee TOTAL for Farms..............-.... 1.914 50 2.6 GRAND TOTAL, .......... cc. 0cc eee 9.849 &.160 49,2 * Census taken by the powdering team at ihe time of treatment. — ** Census according to the ration cards supplied by the Office of the Mayor, L’Arba, — *** Complete census not available. — *’ Due to weather conditions and impassa- Arch. Institut Pasteur d'Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 215 TREATMENTS OUTSIDE L’ARBA VILLAGE. Persons Persons Persons Total Total powdered powdered twice treated number number Ie ea per man treatments | man hours Number Percent Number Percent hour 166 100 vA 42.8 237 63 3.8 467 100 252 50.0 M9 75 9.6 880 74 2 474 4.4 1.051 113 9.3 940 63 5 83 5.9 1.025 M12 9.2 496 38.5 424 9.4 617 76 8.1 607 19.5 95 3.0 702 113 6.2 287 *” 287 60 4.8 3.556 46.3 795 10.3 4.351 612 7.4 104 90 194 47 4A 182 88 an 24 11.3 age 42"” 3 4.0 55 100 55 400 410 dur 80.2 rel 32.5 142 138 400 95 68.8 233 255 19.4 147 52.6 402 5 400 * 5 37 100 28 43.7 65 97 400 8f 83.5 478 34 400 29 93.5 60 25 100 20 80.0 45 35 100 27 7A 62 36 100 12 46.2 38 38 100 29 76.3 7 12 100 & 33.3 16 6L 100 52 85.2 443 43 100 43 400.0 26 166 100 58 34.9 224 84 100 53 63.4 137 26 96.3 u 40.7 37 296 100 205 69.3 50t 31 160 23 74.2 54 153 100 " {53 55 400 " 55 55 100 " oo 69 400 69 166%” 166*’ 38 4.8 1.864 97.4 983 B14 2.847 465 G4 5.706 57.8 4.956 19.8 7.662 41.186 6.6 bility of roads no visit made for second treatment. — *’’ Treated at L’Arba powdering station, but assigned and counted in individual douar (farm) totals. t. XXII, n° 3, septembre 1945. F. L. SOPER, W. A. DAVIS, F. S. MARKHAM, L. A. RIEHL, P. BUCK 216 “duyepaod Jo ou) ye asn 107 Apeer pue uaqer snsaes) ‘SutapMod jo aut ye ueyey susuay , a TEE 69 €8é 089°% 0°09 0S0°1 6°88 08¢ T It 861 SLL 1 Tet enee ss SyUiog Jujt -1epModg peyso07 Aj]8ad 06.) Aaesodurey 10} [e}0] G4 946 Wk O'L9 699 V6 688 9°8 ¥8 816 aSNOH-0]-asnoy LOJ [eIOL 6°9 E8E 0e9°S 0°09 0S0°T 6°88 Osa VI 861 gLL'1 chet “ yRIOL 9 9LI 82l°T L°6S SOF 9°18 40L VEL 00L 408 ToT yy SSBF TT 907 £8 $6 962 rs9 ovE 718 9cy O'S 99 GEG yea ETUC POPY "407 e°9 ait 904 €'€9 98% 0°86 O2F O'L &§ ray costes, moynodif{q -407 gy 948 T#"T 0°49 es9 116 688 8 ¥8 £16 settee [RIO], es 88 L9F 9°49 861 8°16 696 a8 V £63 verses ess *, 9S]3q) 40°] 69 898 $40'T 8°99 cy & 16 069 88 09 089 “torts sy paeasng 107 anoq sanoy uem | syuomyeo yueoseg daquiay quooleg aaqmoNn quao1ed doquon ued aad a i Ne Ot aaquing Jequiog sasuay woo poreeay ad[Ma} padapmod potepaod porepmod joa stosaad (eo. Teo suosieg suosded suosiedg “SNOILVLS SNIVAGMOd AHVHOdWaL GNV DNILSAG ASNOH-OL-3SN0H AO NOSIUVdWO'T) — ‘X] AIdvy, Arch. Institut Pasteur @ Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 27 of war time Arabe women are not willing to work outside their homes. With the return of peace and the easing of transportation and food problems it may be practical to import female assistants from the urban centers where some Europeans and less orthodox Arab women are to be found. On the other hand, if a community were actually confronted with epidemic typhus, local leadership would probably become more effective in solving this problem. TaBLE X: DISTRIBUTION OF TREATED INDIVIDUALS BY SEX AND AGE GROUPS AMONG THE ARAB INHABITANTS OF L’ARBA VILLAGE. No. of Untreated Treated Powdered twice Age group indivi- ee fe ee duals No. fo No. lo No. Jo Men over 16...........+.. 1.074 369 34.5 7102 65.35 206 19.2 Boys 2-16.............085 948 54 5.7 894. 94.3 563 59.4 Women over 16.......... 4.079 56 5.2 F 4.023 94.8 7M 63.9 Girls 2-46..0.0...0...0... 808 24 | 2.9 784 97.1 643 75.9 Infants 0-2............4.. 275 8 2.9 267 97.4 192 69.8 Problems of Community Delousing. — The favorable reception of the delousing treatment by the citizens of L’Arba is better indicated by the low percentage of refusals (1.7% Table VI), than by the per- centage of over-all coverage in the community as a whole. The obvious effectiveness of the anti-louse powder and the personal convenience and ease of applying it without removal of the cloth- ing were primarily responsible for the results attained. Racial discrimination, a question which was raised during the formative phase of the program, never became a problem because the European, both at school and in the home, accepted the treatment without protest. Aside from the personnel difficulties already mentioned, the major problem of the project was administrative : What practical method would reach the greatest number of people ? The treatment was acceptable, but experience showed that it was not as actively sought for as might be expected in such a generally infested popu- lation. The character of the response may perhaps be explained in large part by two factors: the almost Oriental indifference of the Arab born of long association to the discomfort and danger con- nected with blood-sucking ectoparasites, freedom from which the majority of the people have seldom or never known, and the multi- tude of proscriptions that so completely hedge and limit the acti- vities of Arab women. t. XXIII, n° 3, septembre 1945, 218 oF. L. SOPER, W. A. DAVIS, F. S. MARKHAM, L. A. RIEHL, P. BUCK By far the simplest administrative procedure is to set up a central powdering station and invite the people to come to it for treatment. But during the month of its operation the central powdering station in L’Arba was utilized by only 10% of the village inhabitants as compared to 8.7% of the farm dwellers and 3.9% of those living in the douars. Moreover, 92.7% of the patrons at the central sta- tion and 95.8% of those treated at the market place in L’Arba were males (Table XI). It is very probable that had other delousing work been going on simultaneously in the lotissements the response at the central station would have been much greater. Nevertheless, it is evident that this system would fail to reach most of the females and very young males. It appears, therefore, that the treatment must be made more convenient by bringing the facilities closer to the home and establishing rather direct contact with the people as was done by the house-to-house work and the use of temporary powdering stations in the lotissements, farms and douars. TABLE XI, — SEX AND AGE DISTRIBUTION OF TREATMENTS IN THE DOUARS AT THE POWDERING STATION AND IN THE MARKET PLACE OF L’ARBA. Number and Percent of Various Age Groups Treated | Loeati Total Males Females Males Females Infants Seation 16 + 16 ++ 2-16 2-16 0-2 treat- Oe Ne a ees i a ments . : - : No. lo No 9Jo No fy No. Fo No. %p Douars Tenout....... 166 36 | 24.7 39 | 23.3 42 | 25.3 34 | 20.5 15 9.0 Sakamody. . 467 133 | 28.3 91 | 19.5 4123 | 26.3 405 | 22.5 45 3.2 Zerbout...... 880 180 | 20.5 230 | 26.4 244 | 23.9 207 | 23.6 52 5.9 Bousequine. 940 487 | 19.9 233 | 24.8 223 | 23.7 237 | 25.2 60 6.4 Sohane...... 496 129 | 26.0 127 | 25.6 419 | 23.9 108 | 21.9 13 2.6 j Kodja and Bakir,..... 607 220 | 36.2 95 | 15.7 173 | 28.5 94 | 15.3 25 44 Districts Mohieddine..| 405 4 | 13.3 30 | 28.6 36 | 343 18 | 474 7 6.7 Bohane...... 182 34 | 18.7 46 | 233 42) 23.4 42 | 23.4 18 8 TOTAL... .[3.843 933 | 24.3 891 | 23.2 969 | 23.2 [ 845 | 24.9 205 5.4 Powdering Station....] 667 486 | 729 5 007 132 | 19.8 37 $8.35 7 14 Market Place} 2416 446 | 67 6 1 0.5 61 | 28.2 7 32 1 0.5 TOTAL.,..] 883 632 | 71.6 6 0.7 493 | 21.9 ah 49 8 0.9 Arch. Institut Pasteur d’ Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 219 -Considering the distance involved and the difficulties of commu- nication the response in the douars is worthy of comment. Many of the people in these mountain districts travelled on foot for several hours to reach the wayside powdering station in the hills. In two of the six douars all of the inhabitants came in for the first treatment while in two others between 65 and 75% of the residents were dusted. In the remaining two, Khodja and Bakir, which were the largest and the ones therefore where travel and communication the most difficult, the response was poor. They brought the over-all percentage for all the douars down to 46.3. This figure is to be compared with 87.1% coverage in the lotissements of L’Arba village, where pre-census and house-to-house clean-up work established direct contact with the greater part of the population. In the douars explanation of the program and notification of the time and place of the dusting was the sole responsibility of the Chefs de Fractions and the success of the work there was determined by the extent of their cooperation. Unlike the people in the village those in the douars had not the benefit of a convincing preliminary demonstration such as that in Lotissement Bugeaud, which greatly facilitated the work in the other lotissements of L’Arba. In the village of L’Arba itself where 87.1% of the population was dusted, 72.2%, (Table X) of the untreated group were males over 16 years of age. Of the adult males only 65.5 % were dusted, whereas 94% of the rest of the population were powdered. Most of the adult males were employed, many of them on night shifts, in the military installations and depots in the area and it is believed that absence from home and personal inconvenience rather than a reluc- tance to be treated accounts for the high proportion of untreated males over 16 years of age. This interpretation is supported by the fact that in the douars where the men were engaged in the fields the proportion of treated and untreated adult males was about the same as that observed in the other population categories (Table XI). While the reaction to different administrative methods varied from one part of the community to another it is believed that in normal times a sustained delousing program would meet with a very favorable response in a population familiar with its benefits. Second Treatments. — A single treatment gave prompt relief from the discomfcrts of being lousy, which persisted beyond the date set for retreatment. The result was that the people could not be convinced of the need of exerting themselves to seek a second treat- ment so soon. In the douars where the most effort was required to get treatment, only 10.3% of the inhabitants presented themselves for the second powdering (Table VIII). In the village of L’Arba where relatively little effort was involved, only 52.3% were treated a second time (Table VH). The smallest percentage of second treat- t. XX11I, n° 8, septembre 1945. 220 F, L. SOPER, W. A. DAVIS, F. S. MARKHAM, L. A, RIEHL, P. BUCK ments was among adult males, again the group that would have to exert itself the most to be re-treated. Costs of the L’Arba Delousing Project. — The figures listed are based only on necessary expenditures for insecticides, payroll, trans- portation and storage ; staff salaries are not included : Total expenditures ..........--e eee e eee $ 1580.10 Total people treated (once) .............. 9406 Cost per Person 2.6... ccc eee eee eee eee 16.8 Total number treatments given........... 13,708 Cost per treatment ............ 02 ee eee eee 11.5 Cost of insecticide per treatment ........ 6.5 Cost of labor per treatment ............. 1.6 Cost of transportation par treatment .... 2.5 The high cost of the insecticide was largely due to the fact that it was packaged in specially designed shaker envelopes which had to be hand filled. The use of the hand dust pump made the special envelopes unnecessary but the production costs were included in the purchase price of the insecticide. Bulk powder is preferable for use in dust pumps and much less expensive. Transport charges were inordinately high due to the scarcity of vehicles and the market price of fuel. Much of the work in the douars and farms was done with a truck hired at the rate of $ 20 per day. In normal peacetime the cost per treatment would probably be reduced to about one third that of the experimental program. Treatments per Man-hour. -— Tables VII, VHT and IX include data on the number of persons treated per man-hour of work in the village, the douars, farms and institutions. Man-hours are calculated on the basis of the total number of hours for which the workers were paid-not the actual time spent in dusting, census-taking etc. The time spent going to and from a given place of work is included in the man-hours charged against each farm, douar, or lotissement. In the lotissements of the village the time spent in travel was slight, whereas it represents a very considerable part of the man-hours charged against the work in the douars. In small units such as lotissements Lamartine, Carnot and Blandan the women and girls were done by a single worker going from house to house while the men and boys were done at the central station. The result in these small units is an appearance of greater efficiency when compared with the larger units where several crews were at work. Control of Lice. — Among the working class people and farmers of the L’Arba commune lousiness was almost universal. Indirect qualitative evidence of the success of the work was not lacking. Those who came for a second treatment frequently expressed their delight at being able to sleep undisturbed by lice, many of them for the first time since they could remember. Oftentimes workers were offered two to four eggs, worth 25 or 30 cents each, in exchange for Arch Institut Pasteur d’Algérie LOUSE POWDER STUDIES IN NORTH AFRICA 221 a packet of powder. One or two enterprising young workers had to be discharged when it was discovered that they had stolen enve- lopes of powder and sold them at stiff black market prices as high as 70 cents each. Since there is little conceivable misuse to which the powder could be put these incidents indicate that the value of the insecticide was thoroughly appreciated and suggest that were it possible to market the powder through normal commercial chan- nels the community might do much for itself in suppressing lousiness. Control of Typhus. — There was no opportunity to determine the effectiveness of the delousing at L’Arba in the control of typhus. While typhus had been present in the area during the two previous winters, no cases were reported during the time the work was in progress nor were cases of typhus reported in neighboring com- munes. The opportunity of collecting data on the prevalence of typhus was lost by the transfer of Rockefeller Foundation person- nel to Italy to crganize the campaign against typhus in Naples early in December, 1943. SECTION Ill: PRISONER OF WAR CAMP DEMONSTRATIONS (Field Test of 10% DDT-Pyrophyllite Powder) The experiments in the Maison-Carrée prison and the preliminary field test at L’Arba amply showed the practical nature of the method of applying insecticide to infested individuals without remov- ing their clothing. Recognising the advantage of this technique in the handling of prisoners of war, the Surgeon’s Office NATOUSA invited the Rockefeller Foundation Typhus Team to stage a series of demonstrations in the Mediterranean area. The invitation was accepted and arrangements were made for demonstrations in Alge- via, Morocco, Tunis and Sicily during October and November. A small stock of the U.S. Army’s recently adopted 10% DDT- pyrophyllite louse powder was available and it was decided to field test this new preparation in one of the Prisoner of War (POW) camps where demonstrations were to be held. The following is a brief summary of the conditions under which the test was carried out and the results observed, The work was done with the full co- operation of the Base Section Surgeon, the commanding officer of the POW camp and with the assistance of U.S. Army Sanitary Corps Malaria Control Units in the area. — A stockade made to hold approximately 1500 prisoners at one of the Algerian POW camps was selected and work was started on 18 October, 1943. The commanding officer agreed not to add new prisoners to the stockade after the powdering had been done, but did make some withdrawals during the period of observation. t. XXII, n° 3, septembre 1945, 222 F. L. SOPER, W. A. DAVIS, F. S. MARKHAM, L. A, RIEHL, P. BUCK The prisoners lived in pyramidal tents which were numbered individually and by row. Tents in various parts of the stockade were chosen at random and their occupants thoroughly searched for lice. Using the technique previously described, the examina- tions were made under the supervision of the Typhus Team by 12 enlisted men of the Sanitary Corps under the command of Lt. J. F. Sratuwortu. Records were kept of the name and location of each man examined and of the number and developmental stages of the lice discovered. The clothing of 252 prisoners was examined and 193 (77%) were found to be infested. Of the 193 men 75 (30%) had ten or more lice. The application of powder with Dobbins « Superbuilt » No. 133 hand dusters began on October 19th and was completed the follow- ing morning. It is of interest to note that although the enlisted men of the Sanitary Corps started the dusting of the prisoners, within a short time they had the prisoners themselves doing the dusting under their supervision. All of the garments worn by the prisoners together with extra clothing and blankets were powdered. Between 1300 and 1400 prisoners were dusted. On November 4th, after a lapse of 16 days, two of the Typhus Team returned to the POW camp to supervise the follow-up exami- nation and to observe the effectiveness of this first field test of 10% DDT louse powder. The examinations were made by the same personnel as before. Of the 252 prisoners whose garments had been searched previously, 152 were still in the stockage. The examina- tion of the clothing of 151 of these men failed to disclose lice. On the 152nd man 8 nymphal and 2 adult lice were found. Upon questioning, this man said that he had been admitted to the hospital on the evening of the preliminary examination and that he had returned to the stockage after the dusting crews had finished on October 2ist and thus had escaped being dusted. His statements were confirmed by an inspection of the Infirmary records. It was concluded from these observations that, (1) the technique of applying insecticidal powder without removal of the clothing was a thoroughly practical procedure, even when carried out by unskilled personne! and that (2) the 10% DDT-pyrophyllite powder is a highly effective preparation. Other demonstration were held in Morocco on October 22nd, in Tunis on November 12th and in Sicily on November 16th. SUMMARY Field work to test the efficiency of louse powders on naturally infested population groups and to develop methods for the rapid application of louse powders was carried out in North Africa dur- ing the second half of 1943. The powders tested were MYL and Arch, Institut Pasteur d@’ Algérie. LOUSE POWDER STUDIES IN NORTH AFRICA 223 various combinations of DDT. Observations were carried out in a civilian prison, in a rural county with both European and Arab populations and in prisoner-of-war camps. Administrative tech- niques tested included, (1) House-to-house block dusting (2) Delous- ing stations (3) Local temporary delousing stations open only for a day at a previously notified time and place (4) Farm-to-farm delousing (5) Institutional delousing. In the early tests in North Africa, the powder was dusted by hand from shaker tins to the inner surfaces of garments which had been removed from the wearers. In August, the first demonstration was made of the possibility of satisfactorily powdering the clothing without removal from the body. This was followed by tests of various types of hand and power operated dusting equipment. CONCLUSIONS 1. In a closed population group where everyone is treated and the group protected from reinfestation from untreated groups, two treatments of either MYL or DDT at an interval of a fortnight may be expected to reduce lousiness immediately and prevent a dan- gerous degree of infestation ddring a 3 month period. Louse eradi- cation in such a closed population should be possible with a few additional treatments. 2, Individuals, living, working and sleeping, in close contact with heavily infested population groups, show a very low infestation one month after a single treatment with DDT powder. Monthly powder- ing of native labor groups should almost eliminate ali risk of such groups spreading typhus to the people with whom they come in contact. 3. MYL is more rapidly effective than DDT but has a more limited residual action. DDT continues to influence the degree of Jousiness for several weeks. 4, The mechanical application of insecticide without removal of the clothing gives results comparable with those observed. after careful hand application. There is some suggestion in the results that the insecticide Blown forcibly into the texture of the clothing may have a more prolonged effect than has insecticide shaken on the cloth. 5. Vermin infested populations welcome the application of insec- ticidal powders and will make some effort to be treated. The choice of administrative technique used will depend on the distribution of the population to be treated, the existence of transportation faci- lities, and the personnel available to do the work. t. XXIII, n° 8, septembre 1945.