ANTHRAX (Gk. rirl9pu;, coal, carbuncle, malignant pustule: Fr. charbon). A specific, in fectious disease produced by a pathogenic micro organism, Bacillus anthrueis. The disease is also known in different countries as charbon, in flammation of milt; milzbrand, • earbanehio, mjeltbrant, miltbrand, and Siberian plague. In man, it is also called malignant pustule, or car buncle. It is, further, often referred to as splen ic fever and wool-sorter's disease, and. in correctly, as malignant (edema.
Anthrax was the first disease in which the causative relation of pathogenic bacteria was demonstrated. Bacillus anthracis is found in the blood and the tissues of affected animals. The disease is most prevalent among herbivorous ani mals. Its relative frequency in cattle, horses, sheep, and goats varies considerably, according to the region. The camel and various members of the deer family are frequently affected. The disease is rare in swine, and only occasionally met with in the carnivora, such as the dog, eat, panther, lion, tiger, and bear. Anthrax is fre quently transmitted to man, especially through abrasions of the skin of the hands.
Enzobtic outbreaks of anthrax have been known from time immemorial, and in all parts of the globe. In cattle, veterinarians distinguish three forms of anthrax: apoplectic, acute, and sub-acute. In the first type, the animal sud denly drops to the ground as in a poplexy, and dies in convulsions after a few hours. The acute form without external swellings is the one most frequently observed in cattle. The temperature is increased from to •2° C. Muscular trem bling. general prostration, and labored breathing are prominent symptoms. Death supervenes, with signs of asphyxia, in from ten to twenty four hours. In the sub-actite form, which is rare, the symptoms are essentially the same as in the acute form, but less pronouneed.
In both horses and cattle an external form of anthrax occurs, during which tumors or carbun cles develop under the skin. These tumors are distinguished from those of black-leg by the fact that they do not emit a crackling sound on be ing stroked. Before death the discharges of the body may become mucous, or even bloody. In animals which die of anthrax, blood-clots are found on nearly all the vital organs, and the spleen is enlarged to from two to five times its normal size. The symptoms of anthrax are usu
ally characteristic, but a definite diagnosis may always be made by an examination of the blood for the presence of the anthrax bacillus.
In countries subject to the ravages of anthrax. the disease is usually restricted to well-defined areas, which seem to be permanently infected. Anthrax is most common in localities subject to inundation. Ponds of stagnant water and streams polluted with the waste from tanneries and morocco factories may serve as sources of infection. Perhaps the most common means for the spread of anthrax infection is found in the bodies of animals dead of the disease. The an thrax bacillus may gain entrance to the body of an animal in the inspired air, in food or water, or in wounds of the skin. The rapidity with which the different symptoms of anthrax develop depends largely upon the relative resisting power of the animal. The virulence of the anthrax ba cillus is only slowly affected by desiccation.
The bacillus in blood drawn from affected ani mals and dried is destroyed by exposure to di rect sunlight for a period of eight hours. An thrax spores may retain their vitality in the soil for an almost indefinite period, especially if sit uated at some depth. where they are protected from the action of light and oxygen. Putrefac tion destroys the vegetative form of the bacillus, but does not affect the spores. In the fila mentous form the bacillus is killed by a few min utes' exposure to a temperature of 55° to 5S° C. The spores are very resistant to dry heat, a tem perature of 120° to 140° C. for three hours being required to kill them. In 1880, Pasteur, Chain holland, and Roux tried numerous experiments in attenuating, the virus of anthrax by exposure to the air. The oxygen of the air was found to have the effect of rendering the bacillus less pathogenic, especially when cultures were spread out in a thin layer. Toussaint was the first to obtain an attenuated anthrax virus by exposure to heat. Pasteur and others demonstrated that repeated passage through more and more refrac tory organisms increases the virulence of the an thrax bacillus.