Environmentalist groups are blaming domestic sheep grazing on public lands as the culprits for spreading pneumonia to wild bighorn sheep populations. Washington and Oregon’s Departments of Fish and Wildlife have each reported incidences of pneumonia in bighorn sheep herds.
“With the continued inaction on the part of the Forest Service to address the threat these allotments pose to bighorn sheep, these infections are all but inevitable,” said Melissa Cain, bighorn conservation director for Western Watersheds Project. “The Forest Service needs to end permitted sheep grazing in bighorn habitat, or additional bighorn herds will be devastated by this deadly disease or even lost entirely.”
The Washington Department of Fish and Wildlife (WDFW) announced in mid-October the Quilomene bighorn sheep herd in Kittitas County had positive cases of Mycoplasma ovipneumoniae—fatal pneumonia in bighorn sheep. The Quilomene bighorn sheep herd is one of Washington’s largest bighorn sheep herds, with about 220-250 sheep in the herd, according to WDFW. The department lethally removed 12 sheep and tested an additional 12 head to assess if the herd was infected after a domestic ewe was found with several bighorn rams. The tests came back negative.
“This is hopeful news for the Quilomene bighorn herd following their interaction with a domestic ewe this month,” said Mike Livingston, WDFW Region 3 director. “We decided to lethally remove and test animals that were at the highest risk of being infected based on their proximity to the ewe. While these preliminary tests indicate good news, we are going to continue to take additional steps to monitor the herd.”
In a different Washington bighorn sheep herd, the Cleman Mountain herd, a lamb was found dead and tested positive for the disease. The department has yet to determine the source of the bacteria, but doesn’t think it is tied to the Quilomene herd.
WDFW will continue to monitor the affected herds by helicopter and capturing and testing animals on occasion.
The Oregon Department of Fish and Wildlife (ODFW) reported a pneumonia outbreak in the Burnt River Canyon in Baker County, eight months after the disease swept through the county’s other bighorn sheep herd.
The group consists of about 85 sheep, and after a driver on the Burnt Canyon Road spotted a sick bighorn sheep near the road in early October, at least three sheep have died, reported the Baker City Herald. Brian Ratliff, district wildlife biologist at the ODFW’s Baker City office, told the outlet he sent tissue samples from each deceased sheep to a lab for testing. As of Oct. 22, he received inconclusive results from one sheep.
Ratliff noted many infectious agents can cause pneumonia in bighorn sheep, including different strains of viruses and bacteria, and even dust if a sheep is already in poor health. The other two lab results will help determine if the Burnt River Canyon bighorns mingled with the county’s other herd, with domestic livestock, or another source of infection.
Still, environmentalists point blame at domestic grazing on public lands. “Science tells us that domestic sheep need to stay far away from bighorn in order to keep our wildlife safe. The American public wants to see bighorn recovered, so the agencies are going to have to start following the science,” Cain concluded. — Anna Miller, WLJ editor