Epizootic hemorrhagic disease (EHD) devastates white-tail deer, bighorn, pronghorn populations in Eastern Montana, North Dakota

 More than 90 percent white-tail deer suddenly dead along a 100-mile stretch of the Milk River-

Carried by biting midges, EHD kills within a couple days. This epidemic began in late summer. The organism also kills Mule deer, bighorn sheep, elk and pronghorn. White-tailed deer are hit the worst, however.  Local outfitters and officials says it will be a long time before wildlife numbers are restored. This outbreak comes after the severe winter of 2010-11 has already lowered wildlife numbers.

For some reason diseases like this are not perceived by our wolf-hating friends who know that only one thing kills wildlife. Nevertheless, EHD has hit northern Idaho too in the past. Five or years back when my brother-in-law lived in Kamiah, northern Idaho, he had to pull dead deer off his driveway before he could go to work in the morning. An EHD epidemic swept though. I have to wonder why Idaho Fish and Game never mentions this when someone complains to low big game numbers in north central Idaho?

Some think that outbreaks of this disease seem to follow wet springs that leave a lot of mud for the midges to breed.  Several month later the deer begin to die. There is no unanimity on this matter,  this web site says EHD seems to be associated with drought.

Here is an AP story by Matthew Brown on the tragedy. Northern Plains Hit Hard by Deer-Killing Disease



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  1. Salle Avatar

    That’s kind of scary. But then, at the end of the article the potential “upside” to situation is that the spring floods placed cottonwood seedlings up away from the riverbed and the reduced numbers of deer could bring a revival of the cottonwoods that have been devastated over the past several decades.

    I’m sure that there will those who claim that it’s all the fault of wolves and their advocates though…

  2. Mark Gamblin (IDFG) Avatar
    Mark Gamblin (IDFG)

    Ralph –
    EHD is not a factor in the Idaho big game reductions we discuss most often here – i.e. Lolo Zone, Sawtooth Zone and other wolf predation driven elk reductions. For Idaho wildlife, EHD is a significant factor for only whitetail deer and then only sporadically and temporarily. EHD is not known to affect elk in the wild. This link to a WildIdahoNews article – http://www.wildidahonews.com/pages/article.asp?article=3754 – gives a quick overview of the disease and a small 2008 outbreak in the Moscow area. To my knowledge, the last significant outbreak of EHD in Idaho was the 2003 outbreak in the Kamiah area that you note above.

    1. Rita K. Sharpe Avatar
      Rita K. Sharpe

      Have anything more updated?

    1. Rita K. Sharpe Avatar
      Rita K. Sharpe

      Thank you.

    2. Ralph Maughan Avatar
      Ralph Maughan

      Thanks you, Salle. Real scientists discussing an important variety of strains of this wildlife disease instead of marginal thinkers peddling fear.

      1. Salle Avatar

        You’re both quite welcome. I decided to Google it after Rita’s question and found all that… I figured with the search results page would give everyone an opportunity to read as much as they had a desire to.

        I also noticed that this thread has made some “rounds” via email list-serves… I thanked them for sending it around.

  3. Jim Avatar

    Sorry to post this here but I couldn’t find a more appropriate thread.

    Is wolf watching still good in Yellowstone? I have not been there since 2005 and may make a trip this May or June.

    And is it possible to hike in Oregon wolf territory?

    1. Salle Avatar

      Wolf watching in YNP is better than ever since the packs in the western sector of the park are more visible these days. There are more opportunities to view them outside the park, seemingly in all sides, as well. Someone else can fill you in on the OR viewing opportunities.

    2. Ryan Avatar

      Yes, the eagle caps and wenaha tucannon wilderness areas both have wolves are availiable to hike into.

    3. mikepost Avatar

      I had good luck right off the highway near yellowstone lake with the mollies in June…

  4. Larry Thorngren Avatar

    Humans that are bitten by the midges(no-seeums)in the area where deer are dying should be tested to see if they are carrying the virus. The symptoms in deer are very similar to some very deadly virus diseases that humans occasionally get such as Malberg and Ebola.
    While the viruses that cause EHD and Ebola are are from different families,repeated exposure to any virus is potentially dangerous due to their ability to rapidy evolve and change in order to infect new species.

    1. TC Avatar

      Where to begin. Deer don’t have symptoms, they have clinical signs. Humans are not reservoirs or ampliying hosts for either EHDV or BTV, and neither is known to infect or cause disease in humans. Repeated exposure to a virus generally does not cause the virus to evolve, adapt, or mutate to a new host species – virus/host interactions are carefully choreographed and complex relationships, requiring among other things proper ligand/receptor binding and myriad other processes to achieve infection, productive replication and maturation, and release or shedding of infectious virions. The rate at which viral genomes change or mutate is highly variable and dependent on many viral and environmental factors beyond the space I have here. Finally – EHDV and BTV have about as much in common with Marburg and Ebola viruses as human cold viruses have in common with canine distemper virus. Why not be worried about people coming down with respiratory, systemic, or neurological forms of canine distemper?

      This type of post exasperates me as disease expert – this is how public hysteria is started and propagated, usually with negative impacts for wildlife species.

  5. ralph bartholdt Avatar

    “I have to wonder why Idaho Fish and Game never mentions this when someone complains to low big game numbers in north central Idaho?”

    Because herds bounce back when the epidemic is over, they are not continually preyed upon. Clearwater whitetail herds have shown to be productive and have recovered from the 2004 outbreak.

    1. Ralph Maughan Avatar
      Ralph Maughan

      Ralph Bartholdt,

      Yes, yes and yes; I really wonder. I do know this from following a number of wildlife diseases; there is enormous political pressure to highlight, to play up some wildlife diseases such as brucellosis. Others are played down and dismissed. EHD is one of them.

      Loud complaints from conservationists and some hunters have elevated pasturella and other pneumonias in bighorn sheep. Chronic Wasting Disease likewise for deer and elk, but getting action to defeat or even to retard them is like pulling teeth. More exactly, it means lawsuit after lawsuit.


Dr. Ralph Maughan is professor emeritus of political science at Idaho State University. He was a Western Watersheds Project Board Member off and on for many years, and was also its President for several years. For a long time he produced Ralph Maughan’s Wolf Report. He was a founder of the Greater Yellowstone Coalition. He and Jackie Johnson Maughan wrote three editions of “Hiking Idaho.” He also wrote “Beyond the Tetons” and “Backpacking Wyoming’s Teton and Washakie Wilderness.” He created and is the administrator of The Wildlife News.

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Ralph Maughan