Sinonim

Splenic fever, Siberian ulcer, Charbon, Milzbrand

 

Etiology
Anthrax is a zoonotic disease caused by the sporeforming bacterium Bacillus anthracis . Anthrax is most common in wild and domestic herbivores (eg, cattle, sheep, goats, camels, antelopes) but can also be seen in humans exposed to tissue from infected animals, contaminated animal products or directly to Bacillus anthracis spores under certain conditions.

Depending on the route of infection, host factors, and potentially strain-specific factors, anthrax can have several different clinical presentations. In herbivores, anthrax commonly presents as an acute septicemia with a high fatality rate, often accompanied by hemorrhagic lymphadenitis; in dogs, humans, horses, and pigs, it is usually less acute. Bacillus anthracis spores can remain infective in soil for many years. During this time, they are a potential source of infection for grazing livestock, but generally do not represent a direct infection risk for humans. Grazing animals may become infected when they ingest sufficient quantities of these spores from the soil. In addition to direct transmission, biting flies may mechanically transmit B anthracis spores from one animal to another. The relative importance of this mode of transmission during epizootics or epidemics has yet to be quantified but is frequently suspected. Feed contaminated with bone or other meal from infected animals can serve as a source of infection for livestock, as can hay that is heavily contaminated with infected soil. Raw or poorly cooked contaminated meat is a source of infection for carnivores and omnivores; anthrax resulting from contaminated meat consumption has been reported in pigs, dogs, cats, mink, wild carnivores, and humans.

Clinical Signs

• Sudden death (often within 2 or 3 hours of being apparently normal) is by far the most common sign
• Very occasionally some animals may show trembling, a high temperature, difficulty breathing, collapse and convulsions before death. This usually occurs over a period of 24 hours
• After death blood may not clot, resulting in a small amount of bloody discharge from the nose, mouth and other openings

• Due to the rapidity of the disease treatment is seldom possible
• High doses of penicillin have been effective in the later stages of some outbreaks

 

Prevention
Infection is usually acquired through the ingestion of contaminated soil, fodder or compound feed. Sterilisation of meat and bone meal used in animal feed (and more recently its complete removal from cattle feed) has been the main factor responsible for the rarity of anthrax in the UK over the last few years.