Epizootic Hemorrhagic Disease-Breaking it Down

As a 'to-be' hunter, I scavenge the internet, listen to any hunter willing to share stories, read hunting magazine articles and observe deer any chance I get. During this educational hunger, I have repeatedly run across talks of EHD (epizootic hemorrhagic disease). Having a background with some medical terminology knowledge has been helpful in my research on the topic. How does one with no medical background make sense of the medical garble though? Hopefully, I can break it down and make it a little less confusing for the hunting community.

History of EHD

Reports of several deer dying since the 1890's might have been EHD. The cause of the seasonal waves of deaths was diagnosed in several medical terms, but the disease wasn't fully understood or determined at that time. Later looks into case histories suggested that it might have been EHD.

The first occurrence and identification was in New Jersey and Michigan in 1955. Several hundred white-tailed deer died from the disease. It was at that point named epizootic hemorrhagic disease. Epizootic meaning the attack of many animals in a region at the same time. Hemorrhagic means pertaining to the loss of blood.

Cause of EHD

EHD is common to white-tailed deer, but can rarely affect other animals. It is a virus similar to the Bluetongue virus. It is transmitted via biting gnats during the driest part of the season when conditions are right for the gnats. During this time of the year, deer tend to congregate near watering holes where the gnats live. The disease is not contagious from one deer to another or transmittable to humans. The first hard frost typically kills the disease-carrying gnats and ends the spread of the disease for the season. The disease is often fatal, but it is believed that frequent exposure can help build an immunity to the disease.

Signs and Symptoms of EHD

The incubation period for the disease is five to ten days. It is a sudden onset and the infected animal will typically develop signs of the illness about seven days after exposure. Symptoms can include a high fever, unresponsiveness to humans, disorientation, loss of appetite, bloody discharge from the nose, lesions or sores on the mouth and swollen, blue tongues. Deceased deer that have succumbed to the disease are often found near water and it is believed the reason for this is the need to cool off because of the high temperature.

What Hunters Can Do

I have read several articles on this subject and the one thing they all say is to not disturb or kill a deer that you believe may be infected with EHD. Document the location of the deer and its behavior and notify your local game commission. If you find an already deceased deer that you think may have been diseased, again, notify your local game commission. If you harvest an animal this fall that you didn't get to observe much of it's behavior and it has signs of being diseased, do not eat the meat. As mentioned before, EHD is not transferable to humans, but caution is best.

This disease has been around for a while now, but last year a widespread outbreak occurred believed to be caused by the drought. Many of the U.S. states reported cases of EHD. Many debates fired up at that time due to the arguments between game officials and landowners on who was responsible for removing the deer and how to manage the situation. Some states adapted a culling program to help with management. Check with your local game commission on the affects of the disease in your state and see if they have a projection for the 2008 hunting season.

Sources: michigan.gov, wdfw.wa.gov, North American Whitetail magazine-July 2008 issue.