Anthrax

Bacillus anthracis

Changed on: 17.05.2021
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Animal disease categories: D E

Profile

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.

Occurrence

Worldwide, especially frequent in warmer regions (Africa, Asia, South America) with intensive grazing livestock. Anthrax occurs 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.

Host animals

Herbivores are particularly susceptible to the pathogen, especially cattle and sheep, less frequently horses and goats. Carnivores, pigs and humans are less susceptible. Epidemiologically, old places for the disposal of animal carcasses are of particular importance as reservoirs of the pathogen.

Mode of transmission

Anthrax pathogens enter the soil through animal excreta, burial of carcasses and wastewater 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, skin, fur, 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 tiny skin lesions (cutaneous anthrax). Gastrointestinal infections occur after eating raw or insufficiently cooked meat from diseased animals. Inhalation anthrax occurs when very tiny spore-containing dust particles or droplet mists (aerosols) are inhaled.

Incubation period

The incubation period in ruminants averages between 3-5 days. In humans it varies and depends on the dose of exposure and the mode of transmission.

Symptoms

In animals, there is an acute to peracute, septicaemic course with poor blood clotting. Before death, blood may be discharged (especially dark, tar-like) from 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.

Therapy

Various antibiotics are available for the treatment of infected humans, depending on the symptoms and severity of the infection.

Prevention

Control is achieved by regulated carcass disposal and protective vaccination in endangered areas with a previous incidence of anthrax.

Situation in Austria

In Austria, the last cases occurred in cattle in Styria in 1979, in Salzburg in 1980 and in the district of Schwaz in Tyrol in 1988.

Professional information

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, 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 five 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 in drug addicts caused by heroin contaminated with spores have also been reported in Europe. The same or very similar strains were involved, so that it may be possible to assume a previously unknown source of infection.

RKI guide anthrax

Diagnostics

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. Suspected 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. The pathogen is identified by 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.

Contact, Forms

Institute for Veterinary Investigations Mödling, Centre for Biological Safety

Robert Koch-Gasse 17
2340 Mödling

Phone: +43 50 555-38112
Fax: +43 50 555-38529

E-mail: vetmed.moedlingno@Spam@agesno.Spam.at

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