By Mark Fike
Hemorrhagic disease is a cyclic disease affecting deer in the southeast primarily. Typically, the disease hits in waves every four years or so but that cycle can change. On rare occasions, areas can see the disease strike back to back years which is devastating to the deer population.
According to the Virginia Department of Wildlife Resources, HD is caused by two viruses. One is called epizootic hemorrhagic disease virus (EHD) and the other is called bluetongue virus.
Deer with HD are pretty easy to identify. They are usually near water and dying or dead with no real visible signs of trauma. They may be observed with a swollen head or face or tongue and listless. HD is not spread by direct contact from deer to deer but rather through a biting fly. Some call them midges, sand gnats, sand flies, and no-see ums.
The disease does not discriminate at all. Bucks, does and even fawns can get it and die in a few days’ time. Those that don’t die will show signs of the disease during the hunting season. Splitting hooves and sloughing are typical. Some call it blue tongue disease because the tongues are swollen.
Biologists think the deer are found near water because the virus causes a very high fever.
One of the questions that biologists typically get asked is how bad the disease will affect the deer herd. I have listened to the biologists as they answered and can sum up the replies as follows:
During a bad outbreak, you may notice lower numbers via your harvest of deer on your property, but the deer population bounces back within a year or two. Mortality of 50% is possible but very rare. 25% loss is even considered on the high side but it does happen. My county in Virginia once had an estimated third of the deer die from it. However, no HD outbreak has ever “wiped out” a deer population although hunters may feel like it nearly has come hunting season!
Typically, a summer drought is common during years of an HD outbreak. The gnats or midges need a place to breed so when we have a drought, the creeks, swamps and streams leave open mudflats where the midges breed.
Some scientists also feel a mild winter allows more of them to survive which can contribute to more of the gnats to spread the disease. Once a hard frost hits, the outbreaks typically stop. Readers should be on the lookout from now until bow season for HD.
Another concern that some readers may have is about contracting HD themselves or eating the meat. Humans do not get HD. If you eat the meat of a deer that has HD or had HD, you will not get HD or get sick from HD. However, if the deer has a secondary infection from the lowering of their immune system while trying to fight HD, that may cause a concern. If the deer looks healthy when you harvest it, you should not worry.
Take normal precautions that you would take when field dressing any wild animal. If in doubt, properly dispose of the deer. Please do not confuse HD with CWD. GreatAmericanWildlife.com has two articles on CWD.
Author’s note: Much of this information was gathered over the years via the Department of Wildlife Resources in Virginia and conversations with biologists. VDWR acknowledges that they have used information from the following brochure Hemorrhagic Disease of White-tailed Deer produced by the Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602 which is an excellent source of information.