Hemorrhagic disease is the most significant disease of deer in the Southeast.
Each year during late summer and early fall the S.C. Department of Natural Resources (DNR) is contacted related to an occasional sick or dead deer that is found, according to Charles Ruth, Deer/Turkey Project supervisor for DNR. Although there are a number of diseases that can cause sickness and death in deer, the most likely cause during the late summer and fall is hemorrhagic disease.
The disease is caused by certain viruses that are transmitted by biting midges or gnats, commonly called no-see-ums. The seasonality of the disease is related to the life cycle of these insect vectors since they thrive during the warmer months in the Southeast.
Hunters should not confuse hemorrhagic disease with chronic wasting disease since they are very different, Ruth said. Although chronic wasting disease chronic wasting disease represents a significant threat to infected deer and elk populations in North America, there is no evidence that chronic wasting disease occurs in South Carolina. DNR has been conducting surveillance for chronic wasting disease in South Carolina since 1998, and this surveillance will continue.
In addition to being seasonal, hemorrhagic disease appears to flair-up about every three to five years. Said Ruth: "This is probably related to the fact that once deer are exposed to the disease they are more resistant to it. Therefore, if you have disease one year the deer become exposed or inoculated to the disease and you do not see much disease activity until there is turnover in the deer population.
"After several years you are dealing with another cohort of deer and their systems are 'naïve' to the disease. The last time there was significant hemorrhagic disease activity in South Carolina was in 2002, therefore, disease activity could be relatively high this year."
Symptoms of hemorrhagic disease include poor physical condition, sloughing hooves, abrasions or sores on the brisket and legs, and ulcerations on the mouth, tongue, and rumen (stomach). Actual verification of the disease must be through laboratory analysis of blood or certain other tissues.
DNR has monitored for hemorrhagic disease since about 1980 through an effort directed by the Southeast Cooperative Wildlife Disease Study, part of the School of Veterinary Medicine at the University of Georgia. Through this process, the Southeast Cooperative Wildlife Disease Study has determined that hemorrhagic disease is common over most of the Southeast. The severity of hemorrhagic disease varies annually and geographically with cases being mild and scattered in some years while in other years significant outbreaks and mortality can occur.
The Southeast Cooperative Wildlife Disease Study indicates that hemorrhagic disease cases have showed up early and often this year. Positive cases have been confirmed from Virginia, Georgia, Mississippi, Tennessee, Kentucky, Pennsylvania and Indiana and more cases are pending including samples from South Carolina.
Deer likely die in South Carolina each year from hemorrhagic disease, however, there is no indication that a major outbreak has occurred in the state since the mid 1970s. The disease is part of life for deer in the Southeast and fortunately it appears that Southern deer have acquired some immunity to the disease, said Ruth.
Northern deer, on the other hand, are not exposed to the disease as frequently since the insect vector is not as common in cooler climates. For this reason, significant outbreaks and mortality from hemorrhagic disease are more likely in northern deer populations.
Although it is important for hunters to report sick or unexplained dead deer to DNR, there is little that can be done to prevent hemorrhagic disease since it is spread by insects rather than from deer to deer. As with any recommendation for disease prevention, DNR encourages hunters to keep deer populations at reasonable levels, which leads to overall good herd health.
The disease does not pose a threat to hunters, however, hunters should not consume deer or any other game that appears sick or in poor condition.
Find out more about DNR and hemorrhagic disease at www.dnr.sc.gov.