Deer are common in many landscapes, and their interaction with other wildlife raises questions about disease transmission. A significant concern is rabies, a serious viral disease that affects mammals. Can deer contract rabies?
Rabies in the Deer Population
Deer can contract rabies, but its occurrence is remarkably rare. Compared to primary carriers like raccoons, bats, skunks, and foxes, incidence in deer is exceptionally low. In the United States, 7,000 to 9,000 rabid animals are reported annually; raccoons account for about half, while deer cases are infrequent.
The rarity of rabies in deer is largely attributed to biological and behavioral factors. Deer are herbivores, and they are not natural predators. Transmission of rabies typically occurs through a bite from an infected animal, where the virus in saliva enters the bloodstream. A deer attacked by a rabid animal is more likely to be killed by the encounter than to survive and develop the disease, thus limiting the spread within their population.
Signs of a Rabid Deer
Recognizing rabies signs in deer involves observing changes in behavior and physical state, as the virus targets the central nervous system. An infected deer may display a lack of fear of humans, appearing unusually unafraid or approaching people. Increased aggressiveness, where the animal might attack without provocation, can also occur.
Neurological symptoms include disorientation, stumbling, or a drunken-like gait. Paralysis, particularly in the hind legs, can also occur, leading to difficulty with balance or an inability to stand. Physical indicators include excessive drooling or foaming at the mouth, often due to difficulty swallowing.
Distinguishing Rabies from Other Deer Diseases
Other deer diseases frequently present symptoms mistaken for rabies, making accurate identification challenging without laboratory testing. Chronic Wasting Disease (CWD) and Epizootic Hemorrhagic Disease (EHD) are prevalent conditions in deer populations that share overlapping signs with rabies. CWD is a fatal neurological disease caused by prions that damage the brain and nervous system. Deer with CWD typically show severe weight loss, often described as “wasting,” along with listlessness, excessive thirst, and frequent urination. They may also exhibit a drooping head and ears, a rough or dull coat, and an absence of fear toward humans.
Epizootic Hemorrhagic Disease (EHD) is a viral disease transmitted by biting midges; it is not spread directly from deer to deer. This disease commonly causes fever, small hemorrhages around the mouth and nose, and swelling of the head, neck, tongue, and lips. Infected deer often seek water sources due to high fever and dehydration, and carcasses are frequently found near water. While both CWD and EHD can cause disorientation and a lack of fear of humans, CWD is characterized by prolonged wasting, and EHD by acute onset, fever, and swelling, differentiating them from more aggressive or paralytic forms of rabies.
Safety Precautions and Reporting
Encountering a deer exhibiting strange behavior, whether due to rabies, CWD, or another illness, requires caution. Avoid approaching the animal and maintain a safe distance. Do not attempt to capture, handle, or transport a sick or injured deer yourself. Instead, contact your local animal control, state wildlife agency, or police department to report the animal.
In the unlikely event of a bite or attack by a deer, immediate action is necessary. Thoroughly wash the wound with soap and water. Following this, seek prompt medical attention to assess the need for rabies post-exposure prophylaxis (PEP), a series of vaccinations that can prevent the disease if administered quickly after exposure.