EHD is spread among deer, primarily whitetails and often antelope, as well as mule deer and occasionally elk. The disease is contracted by biting midges also known as sand gnats or “no-see-ums.” EHD is one of several hemorrhagic disease/viruses found in wild and domestic ruminants. A related disease, bluetongue virus, affects domestic livestock and wild animals. While EHD can also infect livestock, it has not been proven to spread from deer to livestock or vice versa. The disease poses no physical threat to humans.
High density deer herds may have higher mortality rates; however, the relationship of deer density to the severity of EHD is not clear-cut. Spread of the disease normally stops when the first frost of autumn kills the offending midges. The virus causes bleeding that kills the infected animal within a day or two. Dead animals frequently are found near water, where they go to alleviate a high fever caused by the disease. Symptoms of EHD and bluetongue are identical, so laboratory tests on tissue from fresh carcasses are needed to differentiate between them.
This outbreak in Montana is seasonal since the EHD doesn’t appear as often as it does in warmer climates, but the mortality (death rate) can be higher. In contrast, in southeastern states such as Tennessee and Arkansas the disease is much more common and typically fewer whitetails die from it. Deer herds probably face annual virus activity, which results in herd immunity and protection from the disease. Based on University of Georgia research, whitetail death losses usually are well below 25 percent of the effected population, but can occasionally reach 50 percent. So far EHD outbreaks have not represented a limiting factor to deer population/growth in Montana overall.
The disease is characterized by extensive hemorrhaging, fever and a resultant urge to be near or even immersed in temperature-controlling fresh water. That explains dead whitetails found in or near ponds or even floating in rivers. Animals with the disease may exhibit symptoms such as fever, hemorrhaging of oral and nasal tissues, excessive salivation, nasal discharge, respiratory difficulties, tender hooves and an arched back.
The disease was widespread in Montana this past fall, affecting areas throughout the state in various intensities. The areas that were most effected where north-central Montana, south-central Montana and western Montana around the Missoula Valley. This information was found on the MT FWP website available to anyone interested at the following link: www.fwp.mt.gov/news/newsReleases/hunting/ The breakdown of these areas is as follows:
North-Central – Dead and dying whitetails have been spotted from the Great Falls area to Simms on the Sun River north to the Marias River and even north of Chester. While the number of dead deer is not clear it appears to be pretty aggressive based on people calling about finding dead whitetails. Due to the amount of dead and dying whitetails deer hunters this fall were not allowed to use their general deer license to take antlerless mule deer in five north-central Montana hunting districts. The change took place in HDs 400, 401, 403 404 and 406.The emergency change was due to Epizootic Hemorrhagic Disease (EHD), that was widespread in Montana, including FWP Region 4. Because of EHD, there was a concern that hunters in those five districts will find fewer whitetails and shift to hunting antlerless mule deer, which were legal with a deer A license. In addition, Region 6 over the counter antlerless white-tailed B licenses are no longer for sale.
Missoula – “The deer may show no outward symptoms of disease,” said Vickie Edwards, FWP wildlife biologist in Missoula. “People are seeing healthy looking deer fall over dead.” Nearly 400 dead deer have been reported since the September outbreak began, and FWP sent in samples from several dozen deer for testing. Most deer deaths were concentrated in the Clark Fork River Valley west of Missoula from Harper’s Bridge to approximately 10 miles downstream and in the Mill Creek area northeast of Frenchtown. Other parts of Montana reported outbreaks of EHD this late summer, but this is the first time the disease has been confirmed west of the continental divide in Montana.
Billings – South-central Montana is experiencing a widespread outbreak of hemorrhagic diseases that are killing white-tailed deer, antelope and possibly elk. Reports of dead whitetail deer and antelope are widespread across the region, including further west and south than have been seen before. Biologists have fielded reports of dead animals along the Yellowstone River as far upstream as Springdale, along Rock Creek as high as Boyd, along the Stillwater River to Absarokee and along the Clarks Fork of the Yellowstone to the Wyoming state line. FWP wildlife research specialist Jay Watson said many hunters who stopped at Laurel said they had a hard time finding white-tailed deer to fill their B tags. Hunter observations are beginning to give FWP a clearer picture of the range and severity of an EHD outbreak earlier this year, he said.
For more scientific information about EHD, go to http://www.uga.edu and type EHD in the search bar.