Deadly Bighorn Sheep Disease Confirmed In Quilomene Herd Lamb

Washington wildlife managers say they’ve confirmed a deadly bacteria in the last Southcentral Washington bighorn sheep herd that had been free of the sickness.

WDFW says that samples collected from a dead male lamb found near Jumpoff Ridge south of Wenatchee and Malaga tested positive last month for Movi, or Mycoplasma ovipneumoniae, which causes causes pneumonia in bighorns.


“This is unfortunate news for the Quilomene bighorn herd, Washington’s largest herd,” said Mike Livingston, WDFW’s Region 3 director. “We’re working internally to identify next steps for managing this herd to mitigate effects of the outbreak.”

According to agency spokeswoman Sam Montgomery, a member of the public contacted the district biologist about sick bighorns they’d seen.

Last week saw biologists take to the air to figure out how widespread an outbreak might be and that turned up what appeared to be a sick ewe.

A dead adult bighorn that had been scavenged was also found, according to Montgomery.

WDFW says that it will also be collecting samples from hunters’ harvests – the special permit season for five rams from this area began today – and they’re strongly encouraging the public to report and dead bighorns or sheep coughing or acting sick between Quilomene Bay – located on the west side of the Columbia River/Wanapum Pool across from the Gorge Amphitheatre – and Vantage.

Contact the Yakima office via stray diseased domestic sheep came in contact with seven members of the Quilomene Herd late last September, forcing WDFW to lethally remove six mature rams, three young rams and three ewes that may have been in close contact with the animal and prevent contagions from spreading.

All tested negative at a Washington State University lab for Movi and further initial observation seemed to indicate the herd hadn’t been infected.

But the disease then turned up in Yakima County’s 250- to 300-strong Cleman Mountain Herd, leading WDFW to take the very rare step of offering extra hunting permits halfway through the season.

It all had the Washington Wild Sheep Foundation and Conservation Northwest working to keep more distance between flocks of sheep and herds of bighorns.

“Eliminating interactions between wild bighorn sheep and domestic sheep or goats is the best way to prevent pneumonia outbreaks from occurring in wild bighorn populations. WDFW actively works with sheep and goat owners and other land management agencies to limit those interactions,” an agency press release out today states.

In the rugged country where Idaho, Washington and Oregon come together, biologists think they may have found a way to get rid of the disease: by repeatedly testing animals and removing those that are positive twice in a row, eliminating carriers that are passing it down to lambs.

WDFW also reported that the dead Quilomene lamb was positive for bluetongue. The Eastside and parts of Idaho are seeing a widespread outbreak of the disease, primarily among whitetail deer. The condition is spread by gnats as waterholes dry up in late summer.