Lamb survival to be closely monitored for several years

Another overview story about the bighorn sheep die-offs around the west. Estimates of the death toll have reached 1000 bighorns.

Severe pneumonia outbreak kills bighorn sheep.
American Veterinary Medical Association

About The Author

Ken Cole

Ken Cole is a 5th generation Idahoan, an avid fly fisherman, wildlife enthusiast, and photographer. He is the interim Idaho Director for Western Watersheds Project. We do not accept unsolicited “guest” authors or advertising.

6 Responses to Severe pneumonia outbreak kills bighorn sheep

  1. Drew says:

    question: Is this viral or bacterial pneumonia? If bacterial, which type? If viral, is it mycoplasma? Thanks

    • Ken Cole says:

      The actual agents haven’t been identified. It could be one, it could be a combination, or it could be different in each outbreak.

  2. Drew says:

    Thanks! I assume lung tissue cultures form culled animals a being done so you should have the answer soon. Please update that info.

  3. Drew says:

    Thank you again.

  4. TC says:

    Minor correction – Mycoplasma ovipneumoniae is a bacterium, not a virus. Viral pneumonia generally does not kill bighorn sheep – one or more viruses (RSV, PI3, etc.) may predispose the animals to secondary bacterial pneumonia, that may cause significant disease or mortality (dependent on bacterial species – the most virulent usually being Mannheimia haemolytica). Lungworms, stress, inadequate nutrition and other factors also have some role in large outbreaks of respiratory disease in this species. The jury is still out on how Mycoplasma affects bighorn sheep populations – not known if it is significant pathogen capable of killing many animals, if it predisposes to more virulent bacterial infections, if it will affect survival and lamb recruitment, etc. And finally – isolating one or more potential pathogens from tissues is not definitive evidence that the agents caused the death of that animal – it’s just what it is, the result of one diagnostic test that should be interpreted in light of all field and laboratory findings.


April 2010


‎"At some point we must draw a line across the ground of our home and our being, drive a spear into the land and say to the bulldozers, earthmovers, government and corporations, “thus far and no further.” If we do not, we shall later feel, instead of pride, the regret of Thoreau, that good but overly-bookish man, who wrote, near the end of his life, “If I repent of anything it is likely to be my good behaviour."

~ Edward Abbey

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