This viral disease probably killed over 120 deer in Michigan recently: What you should know

St. Joseph County, Michigan. – A widespread viral disease of deer for which there is no known treatment recently claimed the lives of more than 100 deer in Michigan.

In recent weeks, more than 120 probable cases of Epizootic Hemorrhagic Disease (EHD) have been reported to the Michigan Department of Natural Resources. The cases have been reported primarily from counties in the southwestern Lower Peninsula.

EHD is a viral, sometimes fatal disease that affects white-tailed deer, mule deer, and elk. There is no known effective treatment for EHD in wild populations. The disease is not transmitted from deer to deer.

The DNR Wildlife Health Section and the Michigan State University Veterinary Diagnostic Laboratory recently confirmed EHD virus in a white-tailed deer from St. Joseph County; laboratory results from deer from other counties are pending confirmation.

“Although initial reports indicate that there may be a significant outbreak of epizootic hemorrhagic disease in portions of Michigan's deer population in 2024, this is not necessarily unusual,” said Chad Stewart, deputy chief of the DNR Wildlife Division's Sustainable Populations Section.

According to Stewart, EHD-related deer deaths have been confirmed in Michigan since 2006. During one outbreak, between 50 and 1,000 deer died in isolated areas.

The largest die-off occurred more than a decade ago. Official estimates suggest that more than 14,000 deer died in more than 30 counties in 2012. No cases of EHD were confirmed in 2014 and 2015, but cases have been confirmed every year since 2015.

The DNR expects to confirm additional EHD cases in several counties in the coming weeks. To detect EHD, deer must be tested within 24 hours of death, which requires the entire carcass.

Once EHD is confirmed in a county, the DNR is not required to test additional deer from that county for EHD. Areas where cases were reported in early August are likely to have the most cases, and areas where cases did not appear until mid- or late September will have less severe impacts.

What is epizootic hemorrhagic disease?

Epizootic hemorrhagic disease is a viral disease that occurs in wild ruminants such as white-tailed deer, mule deer, and elk.

The disease is transmitted by a species of mosquito and cannot be passed from deer to deer. It can be fatal, but deer that survive the virus become immune. There is no known effective treatment for EHD in wild populations.

“Deer that survive epizootic hemorrhagic disease develop immunity to the virus, and it is rare for the disease to break out in the same area several years in a row,” Stewart said.

Studies have shown that a warm spring followed by a rainy July and a hot, dry August seems to make an outbreak more likely. That's because the weather makes muddy areas where the fly lays its eggs and reproduces more common. Warm temperatures in late summer and early fall also help the virus reproduce more quickly, according to the DNR.

A severe frost kills the insect and thus stops the spread of the virus.

What should hunters know about EHD?

The DNR does not expect EHD to have widespread impacts on the deer population, but it could impact the population in certain areas. If significant deer mortality occurs in an area, numbers should recover in two to three years.

While hunters should not eat game from visibly sick animals, the DNR stated that game from a deer that suffered from EHD is still safe to eat. There is no evidence that humans can contract the virus from eating game. In fact, according to the DNR, there is no evidence that humans or pets can be infected with the EHD virus.

The DNR stated that EHD outbreaks are characterized by the following features:

• Sick and dead deer are found in or around bodies of water.

• The disease can occur suddenly and severely in deer, but it can also last for weeks or months in a mild stage.

• In severe forms of the disease, the deer lose their appetite and fear of humans, become increasingly weaker, produce excessive salivation and eventually become unconscious.

• Due to high fever and dehydration, infected deer often seek out water to lower their body temperature and hydrate.

Deer carcasses are allowed to decompose naturally; this process does not spread EHD or contribute to outbreaks. Carcasses can be buried so that no body parts are visible, or they can be disposed of in landfills that also accept household waste.

What to do if EHD is suspected?

If you believe a deer has died from EHD, you should contact the DNR.

“If you suspect that a deer death was due to epizootic hemorrhagic disease, please report it to the DNR so we can track cases and better estimate the total number of affected deer in an area,” Stewart said. “Hunters' observations can be especially helpful as they get out in the field and look around this fall.”

Anyone who spots sick or dead deer near water is urged to report it through the DNR website. Eyes in the field Website.