Anthrax is an acute zoonotic disease, primarily of herbivorous animals, which is transmissible to human beings. The causative organism is Bacillus anthracis, often referred to in earlier, and especially in French, texts as bactéridie, the name first bestowed on it by Casimir Davaine in 1863. Humans are infected only secondarily through contact with animals or animal products, and thus the disease in human beings must be considered in relation to anthrax in animals.
The species of domestic animals most commonly affected are cattle, sheep, and goats; pigs, dogs, and cats are less susceptible. Since an enlarged spleen is a classic observation in animals with anthrax, the disease has also been known as splenic fever or splenic apoplexy. In humans the cutaneous form is known as malignant pustule, and the pulmonary or intestinal, industrial type, as woolsorters disease or industrial anthrax. In French the equivalent of splenic fever is sang de rate, in German Milzbrand; other French synonyms include charbon and pustule maligne.
Etiology and Epidemiology
Because B. anthracis produces resistant spores in suitable soils, the disease has long been endemic in many areas throughout the world, with a majority of the outbreaks occurring in Europe and Asia. The Americas, Africa, and Australasia are less affected. Once contaminated with anthrax spores, an area can be extremely difficult to clear, as has been demonstrated on the island of Gruinard off the west coast of Scotland, which was experimentally contaminated during World War II. This is of prime importance for the eipdemiology of the disease because it is rarely spread directly from animal to animal, but almost always through ingestion of contaminated food, either by grazing or, in cooler climates, through imported winter foodstuffs.