CASPER, Wyo. — A pathogenic strain of bacteria that causes lethal pneumonia has killed at least 37 bighorn sheep in the Devil’s Canyon herd, the Wyoming Game and Fish Department said on Monday.
“Since Oct. 14, Game and Fish has documented 37 bighorn sheep mortalities in the Devil’s Canyon herd, which constitutes approximately 10 percent of the population,” said Corey Class, wildlife management coordinator for the Cody Region. “The majority of deaths have occurred in ewes and lambs.”
Game and Fish first learned of the die-off among the herd northeast of Lovell from a landowner report and from a mortality signal from a GPS-collared sheep in the herd.
“We have been working closely with a local landowner who has been key to managing and monitoring this disease outbreak,” Class said. “We greatly appreciate their assistance and cooperation.”
Game and Fish collected samples from carcasses on Oct. 16 and sent them for testing to its Wildlife Health Laboratory in Laramie. An analysis of the samples identified a pathogenic strain of the bacteria Mannheimia haemolytica that can cause lethal pneumonia in sheep.
The source of the outbreak is unknown, Game and Fish said.
The department is monitoring the herd for any potential spread of the disease. Twenty-four sheep in the herd are fitted with GPS collars.
“The collars will now help us monitor bighorn sheep populations from a disease perspective and document additional mortalities,” Class said.
The carcasses from the dead sheep are being disposed of in an effort to limit spread of the disease.
“Our limited experience with this pathogen gives us some hope the outbreak will run its course quickly, with minimal mortalities,” said Hank Edwards, Wildlife Health Laboratory supervisor.
The Devil’s Canyon bighorn sheep herd is estimated to have a total population of 250–300, Game and Fish said. The herd is in Hunt Area 12 in the northwest portion of the Bighorn Mountains.
