What Causes Ehd in Deer? Unveiling the Hidden Culprits!

What Causes EHD in Deer

Deer are fascinating creatures that can be found in various parts of the world. However, there is a disease that affects deer called Epizootic Hemorrhagic Disease (EHD). In this article, we will explore what causes EHD in deer and how it impacts their population and hunting activities.

Understanding EHD

EHD is a viral disease that affects white-tailed deer and other similar species. It is caused by the Epizootic Hemorrhagic Disease Virus (EHDV), which is transmitted through biting midges, also known as the Culicoides species. These tiny insects carry the virus and pass it on to deer when they feed on their blood.

The virus primarily affects the deer’s circulatory system, leading to hemorrhaging and subsequent organ failure. It is worth mentioning that EHD is not contagious between deer, and it cannot be transmitted to humans or pets. Only deer and other susceptible species are at risk.

Causes of EHD

EHD outbreaks are more common in warmer months, particularly during late summer and early fall when midges are most active. The disease tends to occur in areas with standing water, such as marshes and floodplains, where midges breed and thrive. Additionally, drought conditions can concentrate deer populations around water sources, increasing the chances of transmission.

The virus has been found to be more prevalent in certain regions, including the Midwestern and Mid-Atlantic states of the United States. EHD outbreaks have also been reported in parts of Canada, Mexico, and some countries in Europe and Asia.

Symptoms of EHD

When a deer becomes infected with EHD, it may exhibit various symptoms, including:

  • Fever
  • Lethargy and weakness
  • Loss of appetite
  • Dehydration
  • Swollen head, neck, and tongue
  • Excessive salivation or drooling
  • Respiratory distress

These symptoms can lead to severe weight loss and ultimately death in affected deer. It is essential to note that not all deer infected with EHD will show symptoms, making it challenging to estimate the true impact on the deer population.

Effect on Deer Population

Large-scale EHD outbreaks can have a significant impact on deer populations. The disease can result in a high mortality rate, especially in areas where it is introduced for the first time or in populations with no previous exposure to the virus. In such cases, deer can suffer losses of up to 50% or more.

Since EHD outbreaks are more common during late summer and early fall, the effects on deer populations may vary depending on the timing and severity of the outbreak. If an outbreak occurs early in the breeding season, it can lead to decreased fawn survival rates and lower recruitment into the population the following year. This can have long-term implications for deer populations and hunting opportunities.

Impact on Hunting

EHD can significantly impact hunting activities, particularly in areas where deer populations are affected. Hunters may find reduced deer sightings and decreased hunting success rates due to the decline in deer numbers. Wildlife management agencies and hunting organizations often take measures to monitor and assess EHD outbreaks in order to make informed decisions regarding hunting regulations and permits.

Furthermore, EHD can influence the age structure of deer populations. If a disease outbreak affects a significant number of adult deer, it can result in a younger age class dominating the population. This can affect overall trophy quality and hunting experiences, as younger deer may have smaller antlers and less desirable characteristics for hunters seeking mature bucks.

Prevention and Management

While it is challenging to prevent EHD outbreaks entirely, there are measures that can be taken to minimize its impact. Some strategies for preventing and managing EHD in deer populations include:

  1. Controlling midge populations through habitat management and insecticides.
  2. Providing additional water sources during drought conditions to reduce overcrowding around limited water sources.
  3. Enhancing deer habitat diversity to disperse populations and reduce midge breeding grounds.
  4. Implementing hunting regulations that consider the impacts of EHD outbreaks and prioritize deer population management.

These measures, combined with ongoing research and monitoring efforts, can help mitigate the effects of EHD and ensure the long-term health of deer populations.

Frequently Asked Questions On What Causes Ehd In Deer? Unveiling The Hidden Culprits!

What Causes Ehd In Deer?

EHD in deer is caused by a virus transmitted through the bites of midges, small insects commonly found near water sources.

What Are The Symptoms Of Ehd In Deer?

Common symptoms of EHD in deer include fever, weakness, difficulty breathing, loss of appetite, and swelling of the head and neck.

Can Ehd In Deer Be Transmitted To Humans?

No, EHD cannot be transmitted to humans through contact with infected deer or consumption of their meat. It only affects deer and other ruminants.

How Can Ehd In Deer Be Prevented?

Prevention measures for EHD in deer include reducing midge populations, eliminating stagnant water sources, and implementing vaccination programs for captive deer populations.


Epizootic Hemorrhagic Disease (EHD) is a viral disease that affects deer, primarily transmitted through midges. EHD outbreaks can have devastating effects on deer populations, including high mortality rates and changes in population dynamics. Hunters and wildlife management agencies play a vital role in monitoring and managing EHD to minimize its impact on hunting activities and maintain healthy deer populations for future generations to enjoy.

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