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Equine Health Resource


Synonyms: Woolsorter's Disease, Cumberland Disease, Maladi Charbon, Malignant Pustule, Malignant Carbuncle, Mizbrand, Splenic Fever

Anthrax is a rare disease in horses, and more common in food animals. It is a rapidly fatal blood disease caused by a spore-forming bacterium (Bacillus anthracis), which is typically found in warm geographic areas with moist, alkaline soil that favors the organism.

The spores are extremely resistant to temperature extremes and most disinfectants. They can survive in the environment for decades. Horses usually develop Anthrax after eating the spores in the soil, and die within 2-8 days.

Anthrax is a zoonotic disease, meaning that it can be transferred from an infected horse to humans. If you have been exposed to a horse with (or suspected of having) anthrax you should contact your doctor immediately. For this reason, post-mortem examination is potentially dangerous.

Anthrax is a reportable disease, meaning that if a horse has or is suspected of having this disease, vets are required to report it to agricultural authorities (usually the State Veterinarian). These authorities may investigate the case as part of a larger effort to monitor equine health and coordinate with other States and the USDA APHIS in preventing the spread of illness or disease on a national and international level.


  • What measures can we take to prevent infection in my other horses?
  • How can I disinfect my barn & tack, given the difficulty of decontamination?

    There is a vaccine licensed to protect against this disease in horses. Unfortunately, it has a fairly high adverse reaction rate. It should be considered in areas where the risk of this disease is relatively high.

    Helpful Terms & Topics in HSVGWritten, Reviewed or Shared by Experts in Equine Health

    Author: Doug Thal DVM Dipl. ABVP


    Lavoie JP, Hinchcliff KW eds. Blackwell's 5 Minute Vet Consult: Equine. 2nd Ed. Ames: Wiley Blackwell 2008.


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