Anthrax strikes bison on Turner’s Flying D Ranch

Twenty-five domestic bison on Ted Turner’s Flying D Ranch in Gallatin County have been killed by naturally occurring anthrax, according to animal health officials with the Montana Department of Livestock.

“Laboratory tests confirmed anthrax late this morning,” said Dr. Marty Zaluski, state veterinarian for the Montana Department of Livestock, on Wednesday, July 30. “The outbreak has been contained to a single, fully enclosed pasture, and we are aggressively addressing the situation with full cooperation of the landowner.”

Zaluski said the affected area has been quarantined and that disposal of the affected animals is underway.

“We’re fortunate that the landowner recognized the disease early and took the appropriate action,” Zaluski said. “And, even though anthrax rarely spreads from animal to animal, there was no fenceline or other contact with other livestock.”

Anthrax is caused by a naturally occurring bacteria, Bacillus anthracis. Spores of the bacteria can lie dormant in the soil for decades then become active under certain conditions, typically after climatic or ecologic changes such as heavy rains or flooding preceded by drought. Animals are exposed to the disease by grazing or consuming forage or water contaminated with the spores.

Clinical signs of the disease include labored breathing, rising body temperature, staggering, depression, unconsciousness and convulsions. Untreated animals may die within 24-48 hours of exposure, and one or more animals are typically found dead without any recognition of early clinical signs.

A zoonotic disease, anthrax can be spread from animals to humans. Human infection is usually the result of occupational exposure involving direct contact with infected animals or animal products such as wool, hides and horns. Montana has not had a reported case of human anthrax reported since 1961.

Because of its dependence on environmental factors, outbreaks can occur in more than one location of a general area. Vaccines are effective as a preventative, and long-term antibiotics can be used in areas where the disease is confirmed or suspected.

“Anthrax can pop up any place at any time, but this outbreak was in a remote, well contained area,” he said. “Vaccination for livestock in the area is always an option, but we’re not recommending it at this time.”

B. anthracis is fragile and easily inactivated by common disinfectants or exposure to moderate temperatures, and as such, poses virtually no risk to the food chain.

Additional information on anthrax can be found on the department’s web site at http://liv.mt.gov/liv/ah/diseases/anthrax/general.asp.