Outbreaks in the West

Pneumonia Outbreaks Around the West

Bighorn sheep around the west regularly experience pneumonia outbreaks. State agencies decide whether to intervene or not in trying to control an outbreak of pneumonia, depending on whether the herd can easily be reached, how many sheep are sick or dying, and other factors. You can read about some of the larger outbreaks that happened in in 2012 and 2011 in the west, though there were many more outbreaks than are listed here. 


The Wildlife Management Institute's website reports on various outbreaks around the west, and different strategies to control them.


Washington State's bighorns suffered a large outbreak of pneumonia in 2010, in the Yakima River canyon. The state euthanized about one third of the Yakima River bighorns in an attempt to stop the spread of pneumonia. 

Another large outbreak occurred two years later, in April 2013.  This outbreak  severely reduced the Tieton herd near Naches.


In the past several years Montana has lost hundreds of bighorns to pneumonia. Watch this video about bighorn pneumonia in Montana from the Montana Fish, Wildlife, and Parks.

In January 2012, bighorn pneumonia was reported in Yellowstone National Park.


Oregon Public Broadcasting aired this video, featuring Frances Cassirer, about bighorn pneumonia in Hells Canyon. 

Animation of the presence of pneumonia in bighorn sheep populations in the Hells Canyon ecosystem, United States (1995-2011).