By Alex Kline
JOHNSON COUNTY– The outbreak of hemorrhagic disease (HD) that killed over 1,000 deer in Iowa this year has ended, said Department of Natural Resources (DNR) deer project biologist Tom Litchfield. With shotgun season, some hunters might be wondering what the local deer populations will be like after back-to-back outbreak years.
Though this year’s reported cases of hemorrhagic disease was much less than the almost 3,000 suspected deaths of 2012, the quick progression and spreading of the disease can be detrimental to local deer numbers.
“When these outbreaks occur even with in a county there can be some effects on deer population,” said Litchfield. “The outbreaks can be very localized.”
Hemorrhagic disease is a virus spread by biting midges that thrive in hot, dry climates, the reason why the last two years have been so bad, said Litchfield.
“Iowa typically will go a decade without an outbreak of any size,” said Litchfield. “Iowa’s climate does not typically favor the reproduction of the insect.”
Normally, the number of deer killed by hemorrhagic disease in Iowa is well below the last two years’ numbers, ranging between zero to forty suspected HD deaths per year.
Much of this year and last year’s outbreaks were reported in southern and central Iowa, but DNR officials saw more suspected reports coming from northern Iowa than in previous years.
This year fifty-five of the reported mortalities of hemorrhagic disease came from Johnson County. Sixty-six came from Cedar County, and forty-four from Linn.
Even though this year’s epidemic caused an untypical amount of deaths, Litchfield said that the change of the season has ended the outbreak.
“I haven’t had a fresh deer reported for weeks,” said Litchfield. “The disease poses no risk to humans and the outbreak in Iowa ended weeks ago when the adult midges were killed off by freezing temperatures.”
After a deer has been bitten and infected by one of these midges, the virus manifests quickly causing a high fever, dehydration and weakened cell walls causing internal bleeding. Symptoms of an infected deer include stumbling, sometimes drooling, and the animal may be lethargic and unresponsive.
Deer with hemorrhagic disease usually die of internal bleeding and internal fluid build-up within one to four days after the beginning of the fever. Often the bodies are found in good body health near or in a body of water.
“Some deer display varying levels of immunity to HD,” said Litchfield. “There is a chance some hunters might come across a deer that might have been exposed to HD and are recovered.”
Because the disease does not spread to people, the meat of a surviving deer is unaffected and is still safe to hunt. Those deer that have been exposed and have survived hemorrhagic disease may have growth interruptions in their hooves or peeling hoof walls, said Litchfield.