Pneumonia in Bighorn Sheep

Science Center Objects

Bighorn sheep populations are often impacted by outbreaks of pneumonia that are suspected to come from domestic sheep and goats.

During the initial phases of these outbreaks large mortalities occur across all ages of bighorn sheep. During subsequent years, sporadic cases of pneumonia in adult bighorn sheep sometimes occur, but more importantly lambs continue to suffer disease, resulting in low recruitment and stagnant population growth. Pneumonia is one of the biggest hurdles limiting the comeback of bighorn sheep in western North America. A number of different pathogens are often detected during die-off events, which has made it difficult to determine if there is a causative agent that is behind most or all of the outbreaks. Recent evidence suggests that Mycoplasma ovipneumoniae (M. ovi.) is consistently associated with outbreaks and is often associated with a single strain in each outbreak suggesting a recent introduction. 

One of our current projects is to genotype M. ovi. isolates from bighorn sheep, domestic sheep, domestic goats and mountain goats from 11 states. This will help determine if some strains are associated with more severe die-off events and explain some of the variability in severity. NOROCK researchers also provide quantitative support and disease ecology expertise to a team of researchers working on bighorn sheep pneumonia in the Hells Canyon metapopulation of ID, OR, and WA.