Virus killing deer in Washington County

A virus has killed over 150 deer in Iowa this year, including 37 reported cases in Washington County. More deer have died from the virus in the county than in any other county in the state.

The virus is called Epizotic Hemorrhagic Disease (EHD) and is carried by winged insects called midges. All of the 37 cases in the county have been discovered in a two-mile radius just east of the English River Wildlife Area in the northwest corner of the county.

Greg Harris, DNR wildlife biologist who works in Washington, said the dead deer killed by the virus are usually found near a body of water. The virus causes internal bleeding, which dehydrates the deer and makes it seek water. If a deer contracts the acute form of the virus, it will probably die within 72 hours.

Infected animals sometimes have visible lesions on their body left by the virus, but most of the effects are internal. Harris said the virus causes bleeding within the deer?s heart and lungs and causes bruising of other organs such as the liver and spleen.

The midges that carry the disease pass it on to the deer when they bite them. Midges live in mud flats, of which there are many along the English River. Harris said the virus has killed more deer than normal this year because there are more midges. The reason there are more midges is because of the drought.

Washington County Conservation Education Center director Steve Anderson said midges live in mud flats when the creeks dry.

?Even most ponds were full of midges this year because the water level was low,? he said. ?Now that it has rained and the water level has risen, that?s going to help the deer a lot.?

Anderson said the virus has been isolated to a two-mile radius because the deer usually die where they were infected before they have a chance to pass on the disease to deer in other areas. In fact, Anderson has not found any deer in the English River Wildlife Area itself but rather just east of it. He said the virus killed over half the deer that inhabit the area east of the wildlife area.

?The virus is non-discriminatory,? he said. ?It kills bucks, does and fawns.?

Anderson said midges bite humans but there are no cases of humans developing the disease. He said that the disease seems to be limited to ruminants such as deer.

Signs that a deer is infected with the disease include loss of appetite, fearlessness toward humans, excessive salivation and fever. Their fever is one of the reasons they spend time cooling off in the water.

While there is no known treatment for the disease, Anderson asks that persons finding dead deer in or near bodies of water should contact the DNR so they can document or monitor those cases. Animals that have recently died can be tested for the disease.

Anderson said the outbreak of the disease is likely to end abruptly when the midge population drops off, which will come via significant rainfall that raises the water level or a killing frost.