T3 - PH - VET A ANTHRAX PUBLIC HEALTH AND WELF^B^^EQHNICAL' BULLET IN' PH&W GHQ SCAP APO 500 /i94-7 "V . ■ mt Definition —'nthrax (enieHWfirer) is an acute seffticemia (bacteremia) caused by Bacillus anthracis and characterized by enlarge- ment of the spleen, • ’2, History —The history of anthrax is marked by three events of great importance; first, it was one of the first scourges to be des- cribed in ancient literature; secondly, its description by Koch in 1876 marks the beginning of modern bacteriology; and third, when Pasteur im- munized animals against anthrax in 1881, this was the first example of artificial immunization against disease by means of an attenuated culture of the•specific cause of that disease. 3- Distribution—This is general throughout the world, especially in Russia, Asia, Japan, Africa-, the tropics and all warm climates. It affects chiefly herbivora--cattle, sheep and horses, less-often'and. less severely, swine, dogs and chickens. It is,sporadic in man as a local affection of the skin, the lungs, or the intestines. U* Etiology—Bacillus Anthracis—The vegetative form of this mi- croorganism is found in the blood of advanced cases, and in the tissues of those that have recently died,- It is a non-motile gram'positive rod, 2-A microns long, arranged in short chains in the tissues and encapsu- lated. .The organism is readily found in stained smears from the tissue or blood. The spore form exists permanently in the soil, having origi- nated from bacilli dropped in the excretions of either the sick or dead. They form in the feces of the sick, but sporulation occurs only in the presence of air. Under favorable conditions of moisture and temperature, propagation continues in the soil. Spores are carried in hides, brushes, water., fodder, grain, vaccine, bone meal, bones, and other animal products, 5. Modes of Infection a. Soil Infection —Once the soil becomes infected it remains so for jrears. New invasions result from inundation of pastures with tannery refuse, from improper disposal of anthrax cadavers, and from flesh-eating animals and birds that carry the germs in feces or upon the feet. Spores are not found in the buried carcasses and the bacilli is soon destroyed by decomposition of the tissues, b. Ingestion —Cattle and sheep usually contract the disease from infected pastures and streams. Fodder and .grain may also carry the causative organism and occasionally cause- a'sporadic stable infection. Swine, dogs, cats and chickens sicken after eating anthrax cadavers, licking infected blood and hides, or any object that has recently been contaminated. Ingestion is favored by prolonged drought combined with extreme heat, conditions which lead to drinking of polluted water and close grazing. c. Biting Insects —Horses are often inoculated in the skin from blood-sucking flies and mosquitoes, and cattle are likewise exposed, t. d. Wound Infection —Contaminated hands and instruments may in- oculate an operative wound in animals. e. Vaccination Anthrax —In virulent outbreaks any biological product may respond unfavorably when used for vaccination in herds that are exposed. Vaccinations at the height of an intense development of disease, or repeated vaccination at brief intervals during the outbreak may be followed by deaths from anthrax. f. Human Infection —It is largely an occupational disease occurring among those handle hides, hair, wool and bones, or those who come in contact with anthrax cadavers, such as farmers, butchers and veterinarians. Cheap shaving brushes are an occasional source of infection. 6, Morbid Anatomy —Rigor mortis fails and the carcass rapidly undergoes decomposition. The skin sometimes presents edematous swell- ings or necrotic patches, but usually it is normal. The body openings often exude dark-red blood. Beneath the skin, the serous and mucous mem- branes and in the muscles, extensive hemorrhages are frequent. Body cavities * contain blood-stained serum. The spleen is greatly enlarged, hemorrhagic, and degenerated. The liver and kidneys are swollen congested and soft. Hemorrhagic inflammation is nearly always present in the duo- denum and the abomasum. The blood fails to clot. The lungs are congested and the respiratory mucosa is heavily sprinkled with In gen- eral, the post-mortem changes of acute septicemia and toxemia are similar, regardless of the cause. 7. Symptoms —The disease occurs most frequently in summer months in pastured animals, but often it attacks stabled animals. The period of incubation under natural conditions is not readily determined. After ingestion it is probably one or two weeks; after bites and wounds it may be less. 8, Form of Anthrax a. Peracute Anthrax —A rapid fatal general infection of sheep, a frequent form in cattle and occasional in horses. Bloody foam is often expelled from the mouth and nostrils, and blood from the anus and vulva. This is known as the apoplectic form and is the most prevalent in the be- ginning of an outbreak. b. Acute Anthrax —A general infection ushered in with a temp- erature of 105 to 107 degrees F. (4-0 to 4-1 degrees C.) The onset is sudden with marked depression, congestion of the visible mucosa with some hemorr- hages, muscular tremors, cessation of the milk secretion, a rapid pulse, and a high fever. Other manifestations vary according to the intensity of the invasion in different parts of the body. Necrosis and inflamma- tory edema of the skin, enteritis with bloddy diarrhea, hemoglobinuria from kidneys and swollen lymph glands. The terminal symptoms are those of the peracute type with normal or abnormal tomporature. The course is from#one to two days, sometimes longer. (l) In Cattle —The course is somewhat shorter, twelve to twenty-four hours, with swelling at the throat, neck, chest, flanks or back. But enteritis with bloddy diar- rhea is the usual localization. (2) In Horses —Sv/elling of the mammary glands and the sheath with a normal to high temperature of 106 degrees F, (41 degrees C.) On second day, the swelling becomes extensive, cool and painless, appetite poor and the breathing fast, while the temperature drops to 102 or 104, degrees F. (39 to 4-0 degrees C.) As death ap- proaches, colicky pains often appear, the temporat re falls below normal and death occurs suddenly usually on the third day. When swellings develop in the pharyngeal region (edema of the glottis) inspiratory dyspnea develops early. Swellings similarly occur in the lower abdominal and thoracic area. When anthrax appears in horses It often attacks only one or two individuals on a- farm, a suggestion that it is carried by biting flies. (3) In Swine --The chief affection is an inflammatory edema of the throat (edema of the glottis) that soon leads to death from suffocation and septicemia. Bloody froth on the lips, swelling of the throat and face symptoms of choke and petechial hemorrhages of the skin and other symptoms of a general infection along with some swellings over the chest and abdomen. Death usually occurs in from 12 to 36 hours but recovery is occasio- nal. While swine are less susceptible than cattle, they are easily infected from eating contaminated re- fuse, and the disease in swine is limited almost entirely to farms where other species have died of anthrax. c. Subacute Anthrax —This term applies to convalescents from the latter period of an outbreak and to an animal that possesses a natural resistance. One may expect occasionally to find individuals in which the disease is atypical with respect to both course and form. 9. Prognosis —In heavily infected districts, and under exposure to swarms of flies, the disease is highly destructive to all species of domestic animals. When the infection is less abundant and less virulent only a small part of a herd suffers, but the mortality in the sick is from 90 to 100 per cent. Recoveries are mainly confined to local ex- ternal infections, and the last to be attacked in an enzootic. iO. Dia gnosis ■ —Sudden dea ths in pastured st ock may--.be- caused- by . other acute infeot.io.ns~--blackleg, hemoryhagic septicemia, by lightning stroke, 'and by-; .load or = other poisoning, Cattle not infrequently>die at pasture, especially in the spring,' without a diagnosis being made even when the cases are thoroughly investigated,, Recognition depends largely on- finding the bacillus in the blood of the sick or the tissues of the fresh cadaver. Because of the imprrtanc