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Art Lander’s Outdoors: Recent EHD outbreak centered on Eastern Kentucky deer population

In recents weeks reports have been trickling in from landowners finding dead and/or dying deer on their property around farms ponds and small streams.

Samples taken from some of the deer, and sent to the Southeastern Cooperative Wildlife Disease Study in Athens, Georgia, verified that the cause was Epizootic Hemorrhagic Disease (EHD), specifically the EHD-2 strain.

“The epicenter was in Magoffin, Floyd and Pike counties,” said Gabe Jenkins, deer program coordinator for the Kentucky Department of Fish and Wildlife Resources. “From there it expanded north and westward.”

As of Aug. 14, reports of dead deer have been received from 21 Kentucky counties, with five cases of EHD confirmed.

The epicenter of the 2017 EHD outbreak in Kentucky was Magoffin, Floyd and Pike counties. As of Aug. 14, reports of dead deer have been received from 21 Kentucky counties, with five cases of EHD confirmed. (Map courtesy of the Kentucky Department of Fish and Wildlife Resources.)

“From the time we send the samples to the lab, it takes about two weeks to get a confirmation,” said Jenkins.

Additional reports of dead or dying deer could come in for about two more months, or until the first frost.

“Weather conditions (going forward) will determine the severity of the outbreak,” said Jenkins.

To report dead or sick deer, click on this link.

This year’s outbreak is the fifth in the past 10 years in Kentucky, including outbreaks in 2007, 2010, 2012 and 2015. The 2007 outbreak was the worst since Kentucky re-established deer herds in all 120 counties. By late September of that year 2,262 deer were suspected of dying from EHD, with reports from 96 counties.

About EHD

The infectious viral disease, that kills wild ruminants periodically throughout the eastern half of the U.S. and southern Canada, is spread by several species of flying insects in the genus Culicoides. A 1/10-inch midge, Culicoides sonorensis, is the primary vector in Kentucky.

EHD poses no threat to humans, but deer that appear emaciated or listless, should not be harvested by hunters.

Kentucky’s 136-day archery season for deer opens on Sept. 2.

Eating venison from a deer that appears to be healthy, but has EHD, is not a health risk. However, deer infected with EHD sometimes develop secondary infections, so hunters are advised to check deer carcasses carefully. Avoid eating venison if there are any abscesses on the carcass – in the body cavity, muscle tissue or under the skin.

Deer usually die in eight to 36 hours following the onset of observable signs, which include labored breathing, excessive salivation, no fear of humans, lameness, swelling of the head, neck or eyelids, or blue tissue coloration around their mouth and nose. Infected deer that survive for a longer period of time experience lameness, loss of appetite and greatly reduced activity.

High fever causes deer to seek out water. That’s why carcasses are usually found in or near ponds or streams.

Midge Life Cycle

The midge life cycle puts the tiny insects in close proximity to deer, especially during dry conditions in late summer and early fall.

“Drought is commonly associated the EHD, but it’s just one of many drivers that cause outbreaks,” said Jenkins.

A 1/10-inch midge, Culicoides sonorensis, is the primary vector of EHD in Kentucky. Deer usually die in eight to 36 hours following the onset of observable signs. High fever causes deer to seek out water. That’s why carcasses are usually found in or near ponds or streams.

Heavy localized rains can expose mud banks along ponds and creeks, and create mudflats of silt and standing water from runoff.

Females midges lay their eggs in the soil at the edge of shallow waters along creeks, small ponds, natural wetlands and low spots in fields.
An article posted recently on the Quality Deer Management Association (QDMA) website cited some very specific environmental conditions that encourage midge production.

The ideal water is warm, sunlit, high in organic matter, and may be disturbed.

This means perfect conditions for midge reproduction may be created in the typical cattle pond, where cattle disturb and disrupt the shallow margin of the water, preventing plant growth, while defecating and urinating in the water, increasing eutrophication.

Because larvae live in the sediments at the water’s edge, and are not open-water swimmers like mosquito larvae, they have few aquatic predators. Another reason why midges are so adaptable is their tolerance of salts.

Salt levels are often high in cattle ponds and the edges of farm fields, due to salts fed to cattle, salts in inorganic fertilizers, or salts that leach into standing waters from feedlot runoff.

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These salts kill off other insect populations, reducing competition, and giving the midge abundant breeding space.

Once midge larvae mature, they leave the water and morph into winged adults. Only the females feed on blood. The females are crepuscular – most active at dawn and dusk – just like deer.

Midges are not very strong fliers, so calm, humid nights are ideal for feeding. Females use the protein in their blood meals for egg production. When they feed on deer, the viruses they are carrying can be transmitted to deer, or from the deer to the midge.

Dry conditions concentrate deer near water sources, increasing the chances of midges biting infected animals then transmitting the disease to healthy deer. In upland areas, where there’s less moist soil, there’s obviously a lower rate of exposure to EHD.

The virus can’t be spread by deer to deer contact, or from a deer carcass. The EHD virus can’t live in a deer’s body for more than 24 hours after the deer has died.

With so many EHD outbreaks in Kentucky in recent years, some deer may develop antibodies that give them immunity from future outbreaks.

“Eastern Kentucky has not had a significant outbreak in awhile,” said Jenkins. “That makes the deer there more susceptible. We’ll evaluate the outbreak and its affect on deer herds in these counties.”

1Art Lander Jr.

Art Lander Jr. is outdoors editor for KyForward. He is a native Kentuckian, a graduate of Western Kentucky University and a life-long hunter, angler, gardener and nature enthusiast. He has worked as a newspaper columnist, magazine journalist and author and is a former staff writer for Kentucky Afield Magazine, editor of the annual Kentucky Hunting & Trapping Guide and Kentucky Spring Hunting Guide, and co-writer of the Kentucky Afield Outdoors newspaper column.

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