Hemorrhagic Disease in Deer

The Missouri Department of Conservation (MDC) reports moderate levels of hemorrhagic disease (HD) activity in Missouri’s deer population this summer. HD is a general term for epizootic hemorrhagic disease and the bluetongue virus.

MDC has recently confirmed HD in deer in Cole, Greene, Howell, Miller, St. Louis, and Webster counties. MDC has also received at least 305 reports of additional suspected HD cases from locations throughout the state. 

“Hemorrhagic disease is a naturally occurring virus that infects deer through the bite of a native midge commonly called no-see-ums or gnats,” explained MDC Wildlife Health Program Supervisor Deb Hudman. “HD outbreaks are most common in Missouri between July and October and HD transmission ends after a heavy frost kills the midges.”

Clinical signs of HD in deer vary but may include an unwillingness to move, difficulty breathing, and swelling of the head, neck, or tongue.

“HD can cause a high fever, prompting infected deer to seek water,” Hudman said. “Deer that are sick may appear dazed, lethargic, and nonresponsive. Deer that die from HD usually do so in a matter of days following infection and are often found dead in or near water with no outward signs of illness.”

Hudman noted that not all deer die from HD and those deer that survive develop immunity. There is no cure or vaccine for HD and not much can be done to stop the disease from running its course. However, reports of deer with HD can help MDC biologists determine the impacts of the disease on deer numbers in specific areas.

“We receive reports of suspected cases of HD every year and ask the public to report suspected cases of HD to their local MDC office, conservation agent, or to email the information to WildlifeHeath@mdc.mo.gov,” said Hudman.

Hudman noted that humans do not get HD, so handling and consumption of meat from deer that have recovered from the disease poses no health hazard.

The most significant HD outbreak recorded in Missouri occurred in 2012 during an extreme drought.

“Outbreaks tend to be more severe in drought years because deer congregate near the limited water sources where midges are more likely to be present, thus increasing the likelihood of disease transmission,” said Hudman.

Hunters harvested just shy of 300,000 deer during the 2022-2023 deer season – one of the highest harvests on record.

MDC Private Lands Deer Biologist Kevyn Wiskirchen indicated that there may be some impacts during this year’s hunting season in localized areas that have experienced significant deer deaths from HD, but the overall hunting outlook remains good.

“For landowners that have found numerous dead deer this summer because of HD and are concerned about deer numbers on their property, reducing harvest pressure on does will help to mitigate the effects of HD,” said Wiskirchen.

Based on the number of suspect HD reports received by MDC so far this season, Wiskirchen indicated that the locations where taking such measures are needed will likely be very limited.

MDC asks the public to report suspected cases of HD to a local MDC office, conservation agent, or email information to WildlifeHealth@mdc.mo.gov.

Learn more about HD and view of map of suspect HD reports by county at mdc.mo.gov/wildlife/wildlife-diseases/hemorrhagic-disease.

HD or CWD?

HD and chronic wasting disease (CWD) both occur in Missouri and can show similar signs and symptoms.

CWD is a 100%-fatal illness in white-tailed deer and other members of the deer family, called cervids, and is slowly spreading in Missouri.

HD has periodically affected deer in Missouri for decades. HD can have significant short-term impacts on local deer numbers but has never been shown to have a long-term impact on the overall population.

Learn more about the comparison of HD and CWD symptoms, spread, and causes of the two diseases at mdc.mo.gov/hunting-trapping/species/deer/chronic-wasting-disease/cwd-vs-ehd.