Anthrax (dark discoloured spleen in animals) or anthrax (old name for charcoal, charcoal-like scab on the skin of humans) is a disease in animals and humans caused by the bacterium Bacillus (B.) anthracis. Anthrax is a notifiable zoonosis and an occupational disease of veterinarians, farmers and workers who process animal products.
Worldwide, especially frequent in warmer areas (Africa, Asia, South America) with intensive grazing livestock. Only very sporadically in Western, Northern and Central Europe (due to regulated carcass disposal and officially ordered protective vaccinations). The Mediterranean region and Eastern Europe are most affected.
Herbivores are particularly susceptible to the pathogen, especially cattle and sheep, less frequently horse and goat. Carnivores, pigs and humans are less susceptible. Epidemiologically, old washing places (places for the disposal of animal carcasses) are of particular importance as reservoirs of the pathogen.
Anthrax pathogens enter the soil through animal excreta, burial of carcasses and effluent from farms (e.g. tanneries, wool mills) and can survive there for decades. The anthrax spores (permanent forms) can resurface through flooding or digging and re-infect animals. Introduction of the pathogen from other countries is possible via animal products, fertilisers and feed (bone meal, carcass meal, blood meal, hides, skins, hair, contaminated plant feed). Infection in animals usually occurs through ingestion of anthrax spores in feed or drinking water.
Infection in humans usually occurs through minute skin lesions (cutaneous anthrax). Intestinal anthrax occurs after eating raw or insufficiently cooked meat from diseased animals. Inhalation or pulmonary anthrax occurs when very fine spore-containing dusts or droplet mists (aerosols) are inhaled.
In animals, there is an acute to peracute, septicaemic course with poor blood clotting. Before death, blood (especially dark, tar-like) may be discharged from the body orifices. Small ruminants die particularly rapidly.
In cutaneous anthrax in humans, blisters with bloody contents develop first, followed by an ulcer and finally a dry, adherent blackish scab.
Transmission to humans rarely occurs directly from the sick animal. Most often, there is indirect transmission through imported contaminated animal products. In 1979-1981, an anthrax epidemic occurred in a textile factory in Switzerland due to the processing of goat hair from Pakistan; 19 employees were diagnosed late and no deaths occurred.
B. anthracis has a special significance in connection with bioterrorism and biocrime. During the series of attacks in the USA in 2001, when "white powder" was sent by mail and 5 deaths occurred, the pathogen strain "Ames", which was used as a bioweapon, could be isolated in a laboratory of the Austrian Armed Forces from a mailbag of the US embassy in Vienna.
Since 2000, cases of injection anthrax caused by spore-contaminated heroin in drug addicts have also been reported in Europe, involving the same or very similar strains, so that a hitherto unknown source of infection may be assumed.
Indications for anthrax in animals are a previous occurrence of the disease (known anthrax areas) or the proximity to processing plants (e.g. tanneries).
It is important to obtain samples (blood) for bacteriological examination without contaminating the environment with the pathogen. Suspect carcasses must therefore not be opened. Clinically suspect animals must be isolated and must not be slaughtered.
Cultivation of B. anthracis shall only be carried out in a safety level 3 laboratory. Cultural cultivation is considered a safe method of detection. Pathogen identification is carried out using a combination of microscopic, cultural and molecular biological methods. Detection of the two virulence plasmids pXO1 (coding for protective antigen) and pXO2 (coding for capsular antigen) confirms a virulent B. anthracis pathogen strain with the capacity for exotoxin and capsule formation.
Last updated: 10.10.2023