Reports of hemorrhagic disease (HD) in deer have already been received this summer from the Missouri Department of Conservation.
Hemorrhagic disease (HD) is a general term for illness caused by two related viruses: Epizootic Hemorrhagic Disease virus (EHD) and bluetongue virus (BT).
HD primarily affects white-tailed deer and can cause significant mortality events. Clinical signs of HD in white-tailed deer usually begin approximately 7 days after infection. Fever and edema are common, and deer often have a swollen head, neck, tongue, or eyelids. Animals may have reduced appetite, weakness, and loss of fear of humans. Deer die quickly within 8 to 36 hours.
HD is transmitted to an animal host by tiny biting flies commonly known as “no-see-ums” or gnats that are smaller than mosquitoes and other flies.
Diagnosis is based on the combination of clinical signs and virus testing on tissue and blood. Virus identification is essential to distinguish EHD and BT from other diseases of agricultural concern, such as Foot and Mouth Disease.
There is no treatment for HD in wildlife populations, and no wildlife prevention plan currently exists.
The MDC is asking the public to help determine the extent of the disease by reporting suspected cases. Reports from the public help biologists monitor deer health and better understand the impacts of the disease.
“Hemorrhagic disease is a naturally occurring virus in Missouri’s deer population,” explained MDC Wildlife Health Program Supervisor Brigid Niemeyer. “Outbreaks are most common between July and October and typically end after a heavy frost kills the midges that spread the virus.”
Signs of HD in deer can include reluctance to move; difficulty breathing; swelling of the head, neck, or tongue; and unusual behavior such as appearing dazed or unresponsive. The virus can cause high fever, prompting infected deer to seek water. Deer that die from HD are often found in or near water. Death can occur within days of infection, though some deer survive and develop immunity. There is no cure or vaccine for HD.
HD kills deer quickly, making the effects of the disease highly visible. However, the disease does not have long-term effects on the overall health or sustainability of Missouri deer herd. Even after a severe outbreak, the deer population recovers within a few years.
“We care deeply about Missouri deer and deer hunting,” Niemeyer said. “By reporting suspected cases of HD, members of the public can help us track where the disease is occurring and how it’s affecting deer numbers in specific areas.”
Missouri’s most severe HD outbreak occurred in 2012 during an extreme drought when deer gathered around limited water sources, increasing their exposure to infected midges.
Learn more about hemorrhagic disease at mdc.mo.gov/wildlife/wildlife-diseases/hemorrhagic-disease.
To report a suspected case of HD, contact the local MDC office or speak with a conservation agent. Find local MDC offices and agents online at mdc.mo.gov/contact-engage/local-mdc-contacts.
People can also report suspected cases online through MDC’s Wildlife Health Event Reporting Application at mdc12.mdc.mo.gov/applications/WildlifeHealthReporting.
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