CHAPEL HILL - Hemorrhagic disease is killing large numbers of deer in northwestern North Carolina, but it’s not expected to have a significant impact locally.

The disease does not affect people, and eating meat from an infected deer is safe, said Jason Allen, a wildlife biologist with the N.C. Wildlife Resources Commission.

The viruses that cause the disease – epizootic, the most common, and bluetongue – are spread by a biting fly called a midge, or no-see-um.

Infected deer usually develop a high fever, weakness, breathing problems and severe, rapid bloating of the head and neck. There also may be extensive bleeding, flaky hooves, foaming at the mouth and nasal discharge. Infected deer most commonly react by going to water sources and usually die within 36 hours.

The disease is most prevalent from July to November, when the first frost kills off many flies, but infected deer that survive can develop a resistance.

Kindra Mammone, founder and executive director of CLAWS Inc. wildlife rehabilitation group, told the Chapel Hill Town Council last week that the disease could kill half the state’s deer population.

She said she found that information in a North Carolina Sportsman magazine article. It quotes WRC wildlife biologist Chris Kreh, who said his educated guess is that 30 to 50 percent mortality is likely in the northwestern part of the state.

Kreh said it’s the most substantial number he has seen in five years. As of Thursday, he had 1,400 reports of deer in his 11-county area exhibiting symptoms. Very few are being tested to be sure it’s hemorrhagic disease, and state officials won’t know the full effect until later this winter, he said.

Herds in more than a dozen northwestern counties are being hit particularly hard. Surry, Wilkes and Caldwell counties have had the most serious outbreak, but Mitchell, Burke, Alleghany and Cleveland counties also reported a high number of fatalities.

The state is asking hunters in those areas to voluntarily limit the number of deer they kill when this fall’s hunting season opens.

The Triangle region is not experiencing the same problem, Allen said.

Allen said one Caswell County deer was killed this year by hemorrhagic disease, out of 43 suspected cases across an 11-county area.

Orange County had three reports, but only one animal was still fit for testing and the results were negative, he said.

Hemorrhagic disease is common and cyclical in nature. Every five or six years, the state sees more cases, though not usually at this year’s levels, wildlife experts say.

No one really knows why there are more cases this year. Allen said there might be more flies or more deer this year in certain areas, or the northwestern deer may not have been exposed to the disease before, making them more vulnerable.

The disease also tends to show up in years with a hot, wet summer followed by a mild winter, officials say.