Disease outbreak hits John Day River bighorn sheep population

Key Points:

• Several California bighorn sheep along Oregon's John Day River have tested positive for Mycoplasma ovipneumoniae (M. ovi), marking the first detection of this respiratory pathogen in the herd, which is Oregon's largest with about 1,000 individuals.
• M. ovi is linked to severe pneumonia outbreaks in wild sheep, with no available vaccine or treatment, prompting Oregon Department of Fish and Wildlife (ODFW) to conduct necropsies and surveys to assess the outbreak's extent and strain.
• The Day River herd had previously avoided M. ovi, making this a significant concern, especially as similar outbreaks have severely impacted other regional bighorn populations; management efforts focus on minimizing contact between wild sheep and potential disease vectors like domestic livestock and exotic aoudad.
• ODFW emphasizes collaboration with local landowners and tribal partners to manage the disease and prevent its spread, while considering options such as culling or reducing herd density based on ongoing data collection.
• Officials urge the public recreating in the area to report any sightings of dead or sick bighorn sheep to help monitor and control the outbreak.