Hemorrhagic Disease

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In a recent press release the West Virginia Division of Natural Resources (WVDNR) announced that deer from southeastern counties have died from hemorrhagic disease. So, what exactly is Hemorrhagic Disease? It is caused by either one of two closely related viruses. The epizootic hemorrhagic disease virus (EHDV) and the bluetongue virus (BTV) causes disease symptoms that are indistinguishable without lab testing so the general term hemorrhagic disease is used until test results verify which specific virus caused mortality. Both viruses are transmitted by tiny biting flies or midges. These biting midges are also known as sand gnats, flies and no-see-ums. Outbreaks usually occur in mid-August through October and then subside after freezing weather moves in and the biting flies die.

According to the press release “So far this year, deer have been found dead in small areas of Summers, Monroe and Greenbrier counties. Epizootic Hemorrhagic Disease, virus serotype 2 (EHDV-2) has been isolated from Summers County. Hemorrhagic Disease can be caused by either EHDV or Blue Tongue Virus (BTV). No BTV infected deer have been detected. West Virginia samples were sent to the Southeastern Cooperative Wildlife Disease Study located at the University of Georgia, School of Veterinary Medicine where they isolated and identified the virus as EHDV-2. Although this disease usually does not have a major impact on the deer population, the DNR Wildlife Resources Section is surveying the extent of the disease outbreak in the state. EHDV may cause local reductions in the deer herd of 20% or less.” A recent sample from Nicholas County has also came back positive for EHDV-2 virus and so far, there have been 34 deer reported here. Hemorrhagic Disease is not transmitted from deer to deer. Only when the deer is bitten by the fly will it contract the disease. The EHD and BT viruses are more prevalent during drought years when deer are concentrated to limited water sources and numerous animals are more likely to be bitten.

Most of the deer found dead are usually near water sources. This is due to high fever caused by the disease and the deer trying to seek water to cool their bodies. EHDV and BTV also cause excessive hemorrhaging and even deterioration of blood vessels in the vital organs of infected animals. Other symptoms are swollen head, neck, tongue, or eyelids, and difficulty breathing.

Hemorrhagic Disease can cause death in 1 to 3 days but not all deer die from the disease. Some will survive for weeks and even months depending on how healthy a deer’s immune system is and how long it’s been infected. The infected deer will appear sluggish and even emaciated during this period. There are some that survive and will actually become immune to the disease. Deer having survived will have evidence on their hooves. During the onset of the disease the hooves actually peel and split and the evidence is still visible during fall and winter when hunting season is in.

Lesions and ulcers found on the dental pad in the front of the mouth or on the tongue are visible signs that a deer has succumbed to hemorrhagic disease. There are outbreaks that occur almost every year somewhere in the southeastern US. Mortality rates are usually 20% or less of the infected population but in a few instances up to 50% or more have been documented in the southern states. To date there has not been a deer population completely wiped out by EHDV or BTV. It should also be noted that in areas with repeated hemorrhagic disease outbreaks deer population growth was not a limiting factor.

In West Virginia the first documented case of Hemorrhagic Disease occurred in 1981 in Ritchie County. That same year cases were found in Doddridge, Gilmer, Roane, and Tyler Counties. The next documented case happened in 1988 when at least 70 deer died in six counties (Barbour, Harrison, Roane, Upshur, Wood, and Wirt).

One of the largest outbreaks of EHD in West Virginia was responsible for mortality of several deer in Hampshire and Hardy Counties in the summer and early fall of 1993. There were 228 dead deer found in the two counties in the Baker, Rio, Delray, Yellow Spring, Wardensville, and Lost River areas during that outbreak. This same area was hit again in 2016 with landowners finding dead deer near water sources. “EHD does not occur in West Virginia every year; the last large outbreaks of this disease in West Virginia were in 1996, 2002, 2007, 2012, and 2017. EHDV does not persist in deer that survive infection.” Most of the outbreaks that do occur tend to only affect isolated areas of the county instead of the entire county. Hemorrhagic disease is not contagious to humans and it’s not related to chronic wasting disease (CWD) that has been detected in Berkeley, Hampshire, Hardy, Mineral, and Morgan counties. CWD is by far a bigger threat to the overall deer herd than isolated EHD outbreaks. Hunters will no doubt expect to see fewer deer in areas hit with EHD but populations usually bounce back after a year or two. Landowners and hunters in the Summers, Monroe, Nicholas, and Greenbrier county region are urged to report sick or dead deer to the DNR District 4 Office located in Beckley at 304-256-6947. If landowners find sick or dead deer in other regions of the state, they should contact their appropriate DNR district office.