Disease outbreak hits John Day River bighorn sheep population

Breaking News Contests & Promotions Local News Updates Local Alert Forecast Local Alert Weather Warnings THE DALLES, Ore. (KTVZ) — Several California bighorn sheep along the John Day River have tested positive for Mycoplasma ovipneumoniae, marking the first known detection of the respiratory pathogen in the herd.

Cases and health response

The Day River bighorn sheep herd is Oregon's largest, with an estimated 1,000 individuals.

The pathogen, commonly known as M. ovi, is associated with severe pneumonia outbreaks in wild sheep populations and there is no known vaccine or medical treatment available.

Oregon Department of Fish and Wildlife staff are conducting necropsies on dead sheep, submitting samples to the Washington Animal Disease Diagnostic Laboratory and surveying the canyon to assess the extent and specific strain of the outbreak.

Trent Gianella, an assistant wildlife biologist with ODFW in The Dalles, noted that the herd had previously avoided the disease.

“Many bighorn populations in the state have felt the impacts of pneumonia over the years,” Gianella said.

“But the Day bighorn herd has stood out as a stronghold for its size and health both in Oregon and across the West as until now we had not detected M. ovi in this herd.

So, this is disappointing news.”