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Epizootic Hemorrhagic Disease In Michigan Deer

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    Epizootic Hemorrhagic Disease In Michigan Deer By Steve Griffin Our Midland.com 10-19-6 Local hunting and fishing gets so busy this time of year, it s easy to
    Message 1 of 1 , Oct 22, 2006
      Epizootic Hemorrhagic
      Disease In Michigan Deer

      By Steve Griffin
      Our Midland.com
      10-19-6

      Local hunting and fishing gets so busy this time of year, it's easy
      to ignore what's going on elsewhere. Sometimes, though, news brings a
      shudder of recognition. A few years ago, a productive deer hunting
      spot in Nebraska suddenly came up virtually deer-less.

      Where we'd seen pretty good numbers of mature bucks and big does, we
      were mostly seeing lone fawns. First one hunter, then another,
      reported seeing an adult deer running with its lips rolled back, a
      spot or 2 of blood visible. Several of us caught the sickening odor
      of a decaying animal down near a marsh edge.

      Epizootic hemorrhagic disease (EHD), we would learn, had pretty much
      wiped out our hunting spot. Spread by tiny flying insects called
      biting midges, EHD causes severe, flu-like symptoms in deer.

      High fever sends deer toward water for relief, and that's often where
      they die, often less than 3 days after becoming infected. Cattle can
      suffer from it, but dogs and cats don't get it. EHD does not appear
      to affect humans, but hunters are always urged to avoid contact with
      sick animals. If deer survive the infection, they often have cracked
      hooves or heavy hoof overgrowth.

      A hard frost is said to kill off biting midges, ending that year's
      outbreak. Whitetail populations recover, but it can take years.

      This year, a news release reported EHD in west-central Indiana. Up to
      30 EHD-killed deer were found there.

      Then, a week or so ago, Michigan's DNR and Michigan State
      University's Diagnostic Center for Population and Animal Health
      confirmed 2 Allegan County deer infected with EHD. Their carcasses
      were among about 50 dead deer found along southwest Lower Michigan
      rivers and marshes. One was a free-ranging deer and 1 was privately
      owned.

      Bill Moritz, chief of the DNR's wildlife division, said Michigan
      seldom gets hit with EHD, which he said is considered the most
      important viral disease facing whitetails nationwide. It last struck
      here in 1955 and 1974. "When all conditions are right -- weather,
      virus and host -- the disease may occur," he said in a news release.

      We're not alone. So far this year, besides Indiana, EHD has been
      diagnosed in Oregon, Wyoming, Texas, Missouri, Illinois and Georgia.
      If you find a dead deer near water, or if you shoot one with unusual
      hoof growth or hoof damage, contact the nearest DNR office (Bay City,
      Sanford or Gladwin, for most of us), or visit the DNR website at
      <http://www.michigan.gov/dnr>.

      http://www.ourmidland.com/site/printerFriendly.cfm?
      brd=2289&dept_id=472541&newsid=17317931

      ---

      From Patricia Doyle, PhD
      A ProMED-mail post
      International Society for Infectious Diseases

      ProMed -

      EHD is not uncommon in many states. EHD is an acute, infectious,
      often fatal viral disease of some wild ruminants. This malady,
      characterized by extensive hemorrhages, has been responsible for
      significant epizootics in deer in the northern United States and
      southern Canada. A similar hemorrhagic disease called bluetongue also
      occurs in wild ruminants. The 2 diseases are antigenically different,
      although there are similar clinical signs.

      The first occurrence and subsequent identification of EHD occurred in
      1955, when several hundred white-tailed deer ( Odocoileus
      virginianus ) succumbed in both New Jersey and in Michigan. It was
      considered a new disease of deer, and the name "epizootic hemorrhagic
      disease" was suggested to describe its main clinical and pathological
      features.

      Since the initial 1955 outbreak, this malady has occurred primarily
      among white-tailed deer, although occasionally mule deer ( O.
      hemionus ) and pronghorn antelope ( Antilocapra americana ) have also
      succumbed.

      The mode of transmission of EHD in nature is via a 'Culicoide biting
      fly or gnat. 'Culicoides variipennis' is the most commonly
      incriminated vector in North America. A common observation in
      outbreaks involving large numbers of deer (as in Michigan, New
      Jersey, and Alberta) is that they are single epizootics that do not
      recur. Die-offs involving small numbers of deer (as experienced in
      South Dakota and Nebraska) occur almost annually, and the disease
      appears to be enzootic in these areas. All documented outbreaks of
      EHD have occurred during late summer and early fall (August-October)
      and have ceased abruptly with the onset of frost.

      Clinical signs of EHD and bluetongue are similar. White-tailed deer
      develop signs of illness about 7 days after exposure. A consistent
      characteristic of the disease is its sudden onset. Deer initially
      lose their appetite and fear of man, grow progressively weaker, often
      salivate excessively, develop rapid pulse and respiration, and
      finally become unconscious. Hemorrhage and lack of oxygen in the
      blood result in a blue appearance of the oral mucosa, hence the
      name "bluetongue". Between 8 and 36 hours following the onset of
      observable signs, deer pass into a shock-like state, become
      prostrate, and die.

      The gross and histological lesions of EHD are characterized by
      extensive hemorrhage, ranging from pin-point to massive in size, and
      involve different tissues and organs in individual animals. No organs
      appear to be exempt from hemorrhage, with the most regularly involved
      being the heart, liver, spleen, kidney, lung, and intestinal tract.
      Extensive hemorrhaging is the result of interference with the blood-
      clotting mechanism together with degeneration of blood vessel walls.

      Because of its very high mortality rate, EHD can have a significant
      effect upon the deer population in a given area, reducing numbers
      drastically. Hemorrhagic disease can be transmitted to other wild
      ruminants. The EHD virus can infect domestic animals but rarely
      causes disease. Presently there is no evidence that the virus crosses
      into humans.

      Portions extracted from Roselake Wildlife Disease Laboratory site:

      http://www.dnr.state.mi.us/wildlife/Division/RoseLake/Publications/Dis
      ease_Manual/ehd.html

      - Mod.TG

      Patricia A. Doyle DVM, PhD
      Bus Admin, Tropical Agricultural Economics
      Univ of West Indies

      Please visit my "Emerging Diseases" message board at:
      http://www.emergingdisease.org/phpbb/index.php
      Also my new website:
      http://drpdoyle.tripod.com/

      Zhan le Devlesa tai sastimasa
      Go with God and in Good Health

      (as found at http://www.rense.com/general73/eepi.htm )

      ...
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