N. C. Wildlife Resources Commission News Releases

RALEIGH, N.C. (Sept. 17, 2007) – Deer herds in several locations across North Carolina are again experiencing an outbreak of hemorrhagic disease. This virus is one of the most significant infectious diseases of white-tailed deer, and outbreaks are seen almost every year in the southeastern US.

Evin Stanford, deer biologist with the Commission, said the disease has been observed in at least 11 counties in the western piedmont, foothills and mountain portions of the state. While the outbreak of hemorrhagic disease is certainly less than desirable, Stanford said it poses no threat to the citizens of North Carolina.

“Humans are not at risk by handling infected deer, eating venison from infected deer, or being bitten by infected midges,” he said. “The disease is infectious primarily to wild ruminants, such as deer, sheep and antelope.”

The disease is caused by either of two closely related viruses, epizootic hemorrhagic disease (EHD) or bluetongue, and is transmitted through biting flies, commonly called midges. Because symptoms produced by these viruses are indistinguishable, a general term, hemorrhagic disease (HD), often is used when the specific virus is unknown. The N.C. Wildlife Resources Commission has submitted samples to the Southeastern Cooperative Wildlife Disease Study (SCWDS) at the University of Georgia for testing to identify the specific virus, but test results are not expected for at least another week.

According to Stanford, “a number of factors - including the potency of the virus, the immunity level within the deer herd and the population of vectors (midges) - determine the disease’s affect on the deer herd. Outward signs can range from mild illness to death within one to three days following infection. We have been participating in an HD monitoring program with the SCWDS since 1980, when an estimated 5,000 deer died in the upper Coastal Plain and Piedmont regions of our state. Since then, we have gained valuable insight into the epidemiology of this disease.”

Large numbers of North Carolina deer also died from the disease in 1939, 1955, 1961, 1971, 1976, 1988, 1994, 1999, 2000 and 2002, according to Stanford.

“We were not really surprised when we began receiving reports of dead deer in early September,” he explained. “In many of the years when HD affected our herds, conditions were very similar to 2007 - namely a very dry summer. Drought conditions seem to contribute to a large vector population. However, it is surprising to see such high levels of HD activity in some of the far western counties, especially Madison, Buncombe and Henderson. Hemorrhagic disease is much more common in coastal and piedmont areas of the state, and we occasionally see activity in the foothills. It’s quite rare to see high levels of activity this far west.”

Other counties where disease activity has been observed include Davidson, Stanly, Rowan, Iredell, Wilkes, Gaston, Burke and Rutherford.

Since deer in North Carolina have evolved with HD, wildlife officials do not expect severe mortality rates. Stanford estimated that 10 to 25 percent of North Carolina’s deer died in previous major outbreaks. Once a deer contracts a hemorrhagic disease virus and survives, the animal has natural immunity for the rest of its life.

In contrast, HD outbreaks in some Rocky Mountain states led to herd fatality rates of 50 to 80 percent. Biologists attribute the discrepancy to HD’s relatively recent introduction in those areas, as opposed to North Carolina’s lengthy history with the virus.

Stanford indicated that many infected deer which survive the disease will develop lesions or growth interruptions on their hooves. Although this does not confirm the disease, it is a typical sign that the animal most likely did contract the virus.

There currently is nothing to prevent the occurrence of HD in a deer herd. An outbreak can occur in herds with high or low densities; it can afflict deer in good or poor condition. The disease typically runs its course and then subsides soon after the onset of a frost or freeze, when the midge population is essentially eliminated.

Bluetongue and EHD viruses can also infect domestic livestock. Cattle and goats generally show no symptoms or only mild disease when infected. Domestic sheep may develop severe illness when infected with bluetongue virus but do not get sick when infected by EHD virus, according to Stanford.

Persons observing sick or dead deer are asked to contact the Division of Wildlife Management at (919) 707-0050. To learn more about the virus or the N.C. Wildlife Resources Commission, visit www.ncwildlife.org.