Biologists with the North Carolina Wildlife Resources Commission are assuring the public that the outbreak of hemorrhagic disease in western North Carolina in 2012 will not result in a long-term decline in the area’s deer population, even in areas affected the most severely in 2012 — Caldwell, Surry and Wilkes counties.
The deer herd in western North Carolina experienced a substantial outbreak of hemorrhagic disease last year, but the Wildlife Commission has not changed deer hunting regulations as a result of the disease outbreak. Hunters and landowners should consider the effects of the disease outbreak to be relatively short-lived and plan their trips this autumn accordingly, according to Chris Kreh, a wildlife biologist for the Commission.
“It is certainly okay for hunters to resume doe harvest as they have in the past, especially in areas where their objective is to control a robust and sometimes overabundant deer herd,” Kreh said. “Doe harvest is a critical part of any deer management program.”
Kreh and other Commission biologists were able to examine the remains of more than 120 deer that died from the disease last year. By determining the sex and age of the dead deer, biologists were able to assess the disease’s impact on North Carolina’s deer herd.
“Probably the most interesting thing we found was that young does, those that were one or two years old, appeared to be less impacted by the disease than older does and antlered bucks of all ages,” Kreh said. “These young does will be at their peak reproductive age for the next few years which will give the herd substantial opportunity to grow.”
Deer harvest during the 2012 hunting season was considerably lower in a few counties when compared to the 2011 season, according to Kreh. The total reported deer harvest in Caldwell, Surry and Wilkes counties was down by 39, 19 and 47 percent, respectively.
“This reduction in harvest was not simply a result of fewer deer surviving but also because hunters chose to voluntarily take fewer deer,” Kreh said. “Most hunters in the area had questions and concerns about the outbreak and, even though they were still seeing a fair number of deer on their property, they chose to harvest fewer if any deer last year – especially does. The reported harvest in these counties showed a greater reduction in the doe harvest than in the buck harvest.”
The number of deer in these hard-hit counties remains at levels considered biologically acceptable by the Wildlife Commission, which is why deer-hunting regulations were not changed for this fall. In Caldwell, Surry and Wilkes counties, the buck harvest rates in 2012 were 0.9, 1.5 and 1.7 antlered bucks per square mile, respectively. The Commission considers antlered buck harvest rates, which are a reflection of deer abundance, to be biologically unacceptable when they remain below 1 antlered buck per square mile.
Kreh said that the Commission expects antlered buck harvest rates to increase in all of the hardest hit counties in 2013 because:
— The greatest impact of the outbreak was confined to relatively small areas. Deer numbers will increase as deer disperse from nearby areas and from fawns born to surviving does.
— Individual deer that survived last year’s disease had an abundant fall acorn crop in most areas. Soft mast and other foods were also plentiful, allowing survivors to overwinter and enter the fawning season in excellent condition.
— The high number of deer that died from the disease was largely offset by the relatively low number of deer harvested by hunters.
— Deer exposed to EHD-2 in 2012 developed a substantial immunity to the virus, lessening the chance of another EHD-2 outbreak for several years. There have been no reports of hemorrhagic disease in western North Carolina so far this year.
Key Findings from the 2012 Outbreak
Wildlife Commission biologists in 2012 tracked reports of dead deer, collected tissue samples for laboratory testing, and surveyed rivers and streams for dead deer to gauge the impact of the hemorrhagic disease outbreak. Their determinations:
1. The number and location of reports of dead deer revealed that the hardest hit areas were in the heart of the foothills, typically on the eastern side and within 5-10 miles of the Blue Ridge Escarpment.
2. Results of laboratory testing identified the specific strain of the virus as Type 2 Epizootic Hemorrhagic Disease (EHD-2). This is the most common type of Hemorrhagic Disease and is a close relative of the Blue-Tongue Virus, which is a term more common to many hunters.
3. While it is hard to pinpoint the exact mortality rate of this disease outbreak, it seems that mortality rates in the hardest hit areas were similar to what has been seen in significant outbreaks in other parts of North America where mortality rates of 30-50 percent have been documented. However, it is important to note that most areas of western North Carolina experienced substantially lower mortality levels than this.
- Christopher Kreh
NCWRC Wildlife Biologist
Hemorrhagic disease has no human health implications, but is one of the most significant endemic viral and sometimes fatal diseases of white-tailed deer in the southeastern U.S.
Transported by a biting midge (or gnat), the virus enters deer through the blood stream. Common symptoms of sick animals include emaciation, loss of motor control, fever, lameness and swelling of the neck and head. Feverish deer often seek relief near cool bodies of water, resulting in a higher frequency of dead deer near water than on adjacent uplands. Investigations of dead deer usually reveal ulcerations on the tongue, dental pad and palate. The mouth also may be bluish and the skin flush or reddish, particularly noticeable on the inside of the legs and stomach.