Anthrax is caused by the bacterium Bacillus anthracis. The organism is a large, rod-shaped, gram positive, spore-forming bacillus. Anthrax spores are the infectious form of the organism and are highly resistant to sunlight, heat and disinfectant. They are known to survive in soil for up to 80 years.

The natural infection produces very large spores (20-40 µm), which are too large to enter the lower airway. Thus, about 90% of naturally occurring cases of anthrax are the cutaneous form. Humans most commonly contract the disease through cuts, blisters or other breaks in the skin primarily by workers handling contaminated wool, animal hides or hair products. Rarely, humans become infected by eating contaminated meat. By far the most serious and rare form of naturally occurring anthrax arises from inhalation of spores, which need to be about 5 µm in size in order to be readily inhaled into the lower respiratory tract in the large numbers needed to cause disease (estimated to be at least 8,000-10,000 spores).

Dogs and cats are relatively resistant to anthrax in comparison to herbivores such as cattle, sheep, buffalo, bison and moose. Most reported cases in dogs and cats have been from ingestion of raw meat from contaminated livestock carcasses. The incubation period is about 2-7 days with a range of 1-14 days. Once inside the body, anthrax spores emerge from their dormant state and reproduce, releasing three types of toxins which spread and cause a variety of tissue damage.

The anthrax bacillus and its infectious spores cause hemorrhagic and ulcerative stomatitis and pharyngitis, and localize in the pharyngeal lymph nodes before spreading systemically. Resulting clinical signs may include: stomatitis, pharyngitis, tongue carbuncles, facial swelling, head and neck edema, dysphagia, dyspnea from upper airway obstruction or pneumonia, hemorrhagic gastroenteritis, signs of sepsis, and sudden death.

While there have been no documented recent cases of anthrax in dogs and cats, they could potentially become infected from sources of infection maliciously intended for human exposure. This could occur through spore inhalation or from ingestion by self-grooming of a contaminated hair coat.

Veterinarians should contact their State Public Health Veterinarian (listed in the 2001 AVMA directory, pp. 174-177) for information about testing laboratories for their state and the appropriate samples to submit.

Antech Diagnostics does NOT currenttly accept samples for the diagnosis of anthrax.
Local public health officials should be notified immediately if anthrax is diagnosed.

Dogs or cats with anthrax are incapable of transmitting the infection as transmission requires direct contact with the spores. [Even people with inhalation anthrax do not exhale spores.] However, infected dogs and cats could pose a human health risk if their coats were contaminated with spores.

Fresh specimens from infected dogs or cats are not

An appropriate disinfectant for the anthrax bacillus is 0.5% hypochlorite solution (1 part household bleach to 10 parts water). Potentially contaminated hair coats should be washed with copious amounts of soap and water.

Do not open the body of a suspected anthrax case. Blood can be collected with a needle and syringe directly from the heart of a deceased patient. The body should then be double-bagged and frozen pending results of diagnostic tests.

Treatment is not usually attempted. However, with appropriate caution, treatment can be safely administered, as anthrax is not directly transmissible from animal to animal or human. Treatment requires prolonged (6–8 weeks) use of antibiotics such as penicillins, tetracycline, doxycycline, or fluorinated quinolones in addition to supportive care.