In this article, we will look at some of the diseases found among deer.
Hemorrhagic Disease (HD). This disease is caused by two different, related viruses (Epizootic Hemorrhagic Disease virus [EHDV] and Bluetongue virus [BTV]), but the symptoms are indistinguishable regardless of the cause.
Considered one of the largest threats to deer in North America, HD tends to occur in late summer and early fall when the transmitting, biting midges (of the genus Culicoides) are most abundant. Although the disease may go unnoticed in the wild, infected deer can begin displaying symptoms of infection within 7 days. Typical symptoms include loss of appetite; weakness; excessive drooling; reduced activity; fever; fluid accumulation below the jaw and in body cavities; and, eventually, fatal hemorrhages. Because of the fever and fluid loss caused by the HD viruses, infected deer are often found around bodies of water.
Deer that survive the acute form of HD may develop symptoms of the disease including ulcerations in the mouth and interruptions in hoof wall growth that can lead to secondary foot infections. Hoof wall abnormalities are seen most frequently in hunter-harvested deer that are otherwise normal.
Brain Abscesses. Bacterial infections in the skull and brain most often occur in bucks. This is mostly a seasonal occurrence, primarily due to the stages of antler development and fighting. Brain abscesses result from antler casting or fighting with other bucks when infections can develop on the skull near the pedicle. Infection symptoms include circling movements, blindness, poor coordination, emaciation, and lethargy. The meat of these deer is not suitable for human consumption.
Chronic Wasting Disease (CWD). This disease belongs to a group of diseases known as transmissible spongiform encephalopathies. CWD causes brain degeneration.
Because of the lack of a vaccine, no known cure, and other unknowns associated with this disease, it is the most feared of all. Once established, CWD can spread through animal-to-animal contact or soil-to-animal contact, and once contracted is always fatal–even though symptoms can take months or even years to appear.
CWD has no specific distinguishable outward indicators, but a live deer with CWD will display signs of excessive drooling, lethargy, emaciation, drooping posture, tremors, stumbling and will also become oblivious to the presence of predators. Unfortunately, diagnosis can only be confirmed by laboratory examination of brain or lymph node tissue after death. Public health officials advise against consuming the meat of a CWD-infected deer.
These diseases typically affect a small percentage of white-tailed deer; however, landowners and hunters should make themselves familiar with the possible symptoms. Due to the possible risks involved, if you find a sick or dead deer and the cause of death is not apparent, report it to your local conservation officer as soon as possible.
James L. Cummins is executive director of Wildlife Mississippi, a non-profit, conservation organization founded to conserve, restore, and enhance fish, wildlife, and plant resources throughout Mississippi. Their web site is www.wildlifemiss.org.
