An apparent outbreak of EHD — Epizootic Hemorrhogic Disease — is causing concern among Tennessee's deer hunters.
And while Tennessee Wildlife Resources Agency biologists stress that EHD is a naturally-occuring disease that occurs in cycles, they also express concern that the disease is showing up earlier this year than normal.
Early signs are that this could be the largest EHD outbreak in Tennessee since the much-reported deer dieoff of 1999, which killed upwards of 40% of some herds in some extreme recorded instances.
Hunters on the popular TnDeer.Com website have been discussing the outbreak for the past two weeks, and are joined in their discussion by TWRA Region I biologist Alan Peterson and TWRA Big Game Coordinator Daryl Ratyzjcak.
EHD can infect all ruminants, but is most often reported in whitetail deer. The disease is spread by the Culicoides biting fly or gnat. Deer often seek water due to the high fever that results, and as such, dead deer are typically found near water sources such as ponds or streams if infected with EHD. The disease is not always fatal, but is often so, and little can be done to stop its spread, which biologists say will continue until the first frost of the season kills the insects responsible for spreading the disease.
On the TnDeer.Com website, Ratyzjcak said identified a number of counties, primarily in West Tennessee, that have reported EHD deaths, but said that there have been no "major outbreaks" thus far, and that deaths have been limited to fewer than six deer per property so far.
However, Peterson added that it is unusual for EHD to show up this early in the year.
"I usually don't start getting reports until squirrel season opens and the hunters hit the woods," Peterson said. "This is a month earlier than normal, and it is a lot more counties, all of a sudden, than usual.
"Couple that with the increased doe harvests we expect if there is a mast failure as anticipated, and we could see a situation that would need to be considered carefully next year," Peterson said, apparently referring to a potential reduction in the antlerless harvest limits for the 2008 deer season.
"There is almost always some low level of HD every year in the Southeast," Peterson said. "But if an HD outbreak is severe, it can reduce a deer herd. It can kill a lot of deer. We just have to monitor it."
He added that deer infected with EHD do not pose a risk to humans.
"Literally millions have been eaten by people. No human has ever come down with HD. So, the bottom line is they are safe," Peterson said.
While Tennessee hasn't experienced temperatures as hot as those seen this summer since 1999, the year of the last major EHD outbreak, there is no evidence that either drought or heat increase the risk of an EHD outbreak. However, in the same TnDeer.Com discussion, respected Middle Tennessee biologist Bryan Kinkel opined that a severe drought such as that currently being experienced by the state can stress deer and make them more succeptable to succumbing to the disease.
Kinkel also stressed that major outbreaks of EHD have occurred before, sometimes with hunters not even being aware of it, and it hasn't negatively impacted hunting seasons.
With still few people in the woods, it remains unknown how severe this EHD outbreak might be. However, some hunters posting anonymously on the TnDeer.Com website described the situation on properties they are familiar with as severe; one poster reported that a property owner could hardly stand to leave his home due to the stench of decaying carcasses in the air. If confirmed, however, that would likely be an extreme and unusual situation.
EHD wasn't officially recorded as a new disease until the early 1950s. However, the symptoms had been showing up in ruminants much earlier than that, as early as the 1890s, and was usually believed to being other similar illnesses, such as blue tongue.
