Rare disease hits pronghorn near Gillette

The Wyoming Game and Fish Department, in collaboration with the Wyoming State Veterinary Laboratory, is investigating a rare disease outbreak in pronghorn in northeast Wyoming. More than 50 animals have been found dead to date, north of Gillette beginning on Feb. 15.

The preliminary results identify Mycoplasma bovis as the pathogen causing the mortalities.

Mycoplasma bovis should not be confused with Mycobacterium bovis that causes tuberculosis in cattle. They are two unrelated bacteria that cause very different diseases.

Game and Fish is monitoring the situation, has dispatched field personnel to the area and is working with Wyoming State Veterinary Laboratory researchers to study this outbreak in more detail.

The source of infection of the M.bovis, the ability to predict the duration and the geographic distribution of this outbreak in pronghorn is unknown at this point.

“While outbreaks causing mortality in wildlife are rare, this is not the first occurrence of M. bovis being linked to pronghorn mortalities in Wyoming,” said Game and Fish Wildlife Disease Specialist Terry Creekmore.

The first reported pronghorn cases occurred in 2019, when the Gillette area experienced a similar outbreak northeast of town involving more than 75 animals. The outbreak started at a similar time in 2019 and then tapered down by about the start of April.

Game and Fish continues to monitor for this disease across the state. With the exception of the Gillette area, this bacteria has not been reported as associated with significant mortality in other wildlife populations in Wyoming.

To date this pathogen has not been shown to affect domestic pets such as horses, dogs or cats and is not considered a human health risk. Area residents who see or find sick and/or dead pronghorn are encouraged to contact the local game warden, biologist or Sheridan Regional Game and Fish office at 307-672-7418.