State of Montana wildlife officials have confirmed that bighorn sheep from the East Fork Bitterroot herd south of Darby recently died of pneumonia. The nearly always fatal respiratory disease was first suspected after hunters reported seeing coughing bighorn sheep near the East Fork.
Jennifer Ramsey, Montana Fish, Wildlife and Parks wildlife veterinarian in Bozeman said the state will attempt to cull more sheep from the herd over the coming weeks.
"Our top priority is to remove sick and dying animals and to collect biological samples for testing," she said. "Additional laboratory test will determine the specific strain of the bacteria, and removing sick animals could help slow the spread of the disease."
Once bighorns contract pneumonia, they die within a few days. There are no known vaccines to prevent pneumonia in wild sheep.
The East Fork bighorn sheep herd was established in 1972 when 35 sheep were transplanted there. There were 185 sheep counted last year during an aerial survey last March.
In extreme cases, pneumonia-related outbreaks among bighorn sheep can result in herd "die-offs." The most recent case in Montana occurred in the Elkhorn Mountains near Helena. Similar die-offs happened in the Highland Mountains in 1995 and in the Tendoy Mountains in 1993.
There is no evidence the disease originated in domestic sheep or goats.
Reprinted in part from The Missoulian