November 2001

INFORMATION PAPER

SUBJECT: Management of Military Animals suspected to have Anthrax

1. Purpose. To provide information for diagnosis, sampling, and necropsy of military animals suspected to have anthrax.

2. References:

a. Information Paper, MCVS-SC-D, 19 October 2001, SUBJECT: Management of Military Working Dogs Potentially Exposed to Anthrax Spores.

b. Information Paper, MCVS-ATC-M, 6 November 2001, SUBJECT:Management of Military Working Horses Potentially Exposed to Anthrax Spores.

3. Anthrax occurs most often in ruminants that ingest spores of Bacillus anthracis while grazing. Horses also acquire anthrax by grazing, but are less susceptible than ruminants. Carnivores and pigs are the least susceptible and natural disease is usually due to eating undercooked meat from infected animals. In ruminants and horses, gross lesions may include blood oozing from body orifices, hemorrhagic gastroenteritis, and an enlarged congested spleen. In carnivores, gross lesions may include pharyngeal swelling or cervical abscesses.

4. If an animal dies and anthrax is suspected based on history or presentation, do NOT open the carcass. First don appropriate personal protective equipment, to include surgical mask, gloves, goggles or face shield and disposable coverall. Obtain a peripheral blood smear from the ear or toenail and percutaneous heart blood samples and/or splenic aspirates for cytology and culture. In carnivores, also obtain aspirates from any swollen areas in the head and neck. Examine Wright’s stained smears for the presence of large, blunt-ended, “box-car” bacilli. In most cases of terminal anthrax, bacilli will be present in the blood for at least 24 hours. Submit blood cultures and nasal/pharyngeal swabs to your local or state diagnostic laboratory, and notify them that anthrax is suspected.

5. If anthrax infection is confirmed, the entire carcass and all contaminated waste should be incinerated. Necropsy should only be performed in a Biolevel 3 facility. Thoroughly disinfect all contaminated environmental surfaces with undiluted bleach. Personnel with exposure to the carcass or clinical samples should scrub with soap and water and disinfect their skin with 0.5% hypochlorite (1 part bleach in 10 parts water), then notify their Primary Health Care Provider immediately.

6. If an animal is found dead without premonitory signs and has a history of potential exposure to anthrax, examine smears of peripheral blood and/or percutaneous splenic aspirates before opening the carcass. Remember, if the animal has been dead more than 24 hours or has been treated with antibiotics, bacilli may not be present.If there is a strong suspicion of anthrax despite a questionable blood smear result, do NOT perform a necropsy. Otherwise, proceed as usual with necropsy, utilizing appropriate personal protective equipment, to include surgical mask, gloves, goggles or face shield and disposable coverall. During necropsy, obtain specimens of heart blood, lung, liver, spleen, and mediastinal and mesenteric lymph nodes for culture.

7. Anthrax is a reportable disease. All confirmed cases of anthrax must be reported to your state veterinarian and military chain of command. A list of state veterinarians can be found at www.aphis.usda.gov/vs/sregs/official.html In addition, if bioterrorism is suspected, contact the Weapons of Mass Destruction coordinator of your local FBI field office. A list of FBI field offices can be found at www.fbi.gov/contact/fo/info.htm, or contact your local Provost Marshall for phone numbers.More detailed information on anthrax can be found on the World Health Organization webpage at http://www.who.int/emc/diseases/anthrax/index.html.

8. For further information contact the Department of Veterinary Pathology at the Armed Forces Institute of Pathology at 202-782-2600 or via email at afipvet@afip.osd.mil.

Also check out AFIP's Inhalation Anthrax Web Site (anthrax in humans), for histopathology images.