CRAWFORD COUNTY - The annual excitement in anticipation of deer hunting is starting to occupy the minds of area hunters. So, the news of over 100 dead deer in Crawford County, reported by the DNR last week, has really caught people’s attention.

The deer are dying from a seasonal virus called Epizootic Hemorrhagic Disease. EHD is common in states to our south, but is only rarely seen in our area. Deer have also been reported dead from the disease in Iowa and Minnesota. EHD is a virus that is transmitted by bites from gnats and other insects, and cannot be transmitted from animal to animal.

“It is a particular species of gnat that transmits the disease, and our area is at the very northern range of its territory,” Viroqua DNR Wildlife Biologist Dan Gotz explained. “The probable reasons that we are seeing an outbreak this year is because it has been such a wet year, and river flooding will leave behind mud flats which create ideal conditions for the gnats.”

Gotz said that there have been no confirmed cases of EHD in Vernon County. Monroe County Conservationist Bob Micheel also confirmed that there had been no sign of EHD in Monroe County either.

Doug Duren, a Richland County landowner and ardent Chronic Wasting Disease (CWD) activist, says that the outbreak in Richland County, as far as he knows, has been relatively smaller than in Crawford County. By contrast, Richland County has been the epicenter in recent years for the spread of CWD into surrounding counties.

“EHD is a much shorter-lived problem for the deer population, and the current outbreak should end with the first frost,” Duren said. “CWD is the real problem that people need to focus on. Its spread is overtaking our area, and we need a proactive effort to get hunters out in the field, increase our harvest, increase sampling and make dumpsters widely available for carcasses.”

What is EHD?

According to the Center for Food Security and Public Health, deer can develop clinical signs in as little as seven days after exposure. Deer infected with EHD lose their appetite, lose their fear of people, grow weak, show excessive salivation, develop a rapid pulse, have a rapid respiration rate, show signs of a fever which include lying in bodies of water to reduce their body temperature, become unconscious, and have a blue tongue from the lack of oxygen in the blood. 

The head and neck of infected deer may swell. One of the most common characteristics of deer with the chronic form of EHD is the sloughing or breaking of the hooves caused by growth interruptions. Deer with chronic EHD often become lame due to these hoof problems.

Wisconsin DNR’s Bret Owsley explained that in order to test deer for EHD, the carcass must be found within 48 hours of death.

“The reason the press release put out by us said that three deer in Crawford and two deer in Richland counties had been identified as having died from EHD, but later said that over 100 had died is because only a few of the deer were found soon enough to take a sample,” Owsley explained. “For the others, they were found near water and in groups, and that leads to conclusion of a very strong likelihood that they too were killed by EHD.”

Owsley said that of the over 100 deer believed to have died of EHD, almost all of them have been found in southern Crawford County, in the Steuben, Wauzeka, and Eastman areas, and only a few in Richland County.

“Unlike CWD, EHD is a short-lived phenomenon,” Owsley said. “It is not a population-limiting level or even a county-wide level threat.”

Other species

EHD is not a threat to humans, although it is not recommended that humans consume the flesh of an animal that is suffering from the virus.

Outbreaks of EHD have been reported in cattle, although it is rare for them to develop the disease or die. Sheep may develop clinical signs; however, this is also rare. EHD is often called bluetongue, but this is incorrect. 

Bluetongue virus is closely related to EHDV, and has similar clinical signs, but it is a different disease. Bluetongue is a serious disease in cattle, as well as other ruminants, and can have a significant effect on international trade. Testing at animal health laboratories is necessary to distinguish between the viruses that cause bluetongue and EHD.

The Independent-Scout has received one report of a cow being diagnosed as infected with EHD near Boscobel. It is also reported that the cow, with proper care, survived the infection.

According to Dr. Steve Anderson of the Apple Valley Vet Clinic in Gays Mills, he has not personally seen a case of EHD in cattle, but did have one owner call him about it.

“The owner treated the cow himself and it pulled through,” Anderson said. “The main thing, as with any viral infection, is hydration, and access to good feed. Sometimes infected cattle will get a sore mouth and refuse water and food. If secondary infections develop, then antibiotics might also be needed.”