Disease Outbreaks in Deer Not Uncommon

Washington State University veterinary clinic staff confirmed area deer are infected with a common disease referred to as Epizootic hemorrhagic disease or EHD. This disease, carried by a biting midge, must be carried through the insect vector to be passed on. It cannot be transmitted directly from one deer to another. The term Ôepizootic' denotes a disease that is temporarily prevalent and widespread in an animal population. Since the initial outbreak of EHD in 1955, this disease has occurred primarily among white-tailed deer (O. virginianus), although occasionally in mule deer (O. hemionus) or pronghorn antelope (Antilocapra americana). Present in the United States for over 50 years, EHD has not caused significant long-term decreases in deer populations. This disease occurs in most years in the Clearwater Region. "Some years it manifests itself more than others. It is typical to see more of an outbreak on hot and dry years. This has certainly been one of those years, says Clearwater Regional Supervisor, Jerome Hansen. There is no evidence that humans can contract the EHD virus either from the midge or from handling and eating venison. Cats and dogs do not contract EHD. Among livestock, only cattle have been documented to be clinically affected by EHD and then only very rarely with a very mild clinical course that lasts a few days with lethargy, low-grade fever and some loss of appetite. Numerous reports have been made in the Grangeville, Harpster, Juliaetta/Kendrick , Troy/Deary, Whitebird and a other surrounding areas. "There are still plenty of deer to hunt, but overall abundance could be affected locally," said Clearwater Wildlife Manager, George Pauley. As its name implies, deer often suffer from extensive hemorrhage. Hemorrhage is most often associated with the heart, liver, spleen, kidney, lung or intestinal tract, although no organs appear to be exempt. Extensive hemorrhaging is the result of interference with the blood-clotting mechanism together with degeneration of blood vessel walls. White-tailed deer develop signs of illness about seven days after exposure to midges. Deer in the early stages of hemorrhagic disease may appear lethargic, disoriented, lame or unresponsive to the presence of humans. As the disease progresses the deer may salivate excessively or foam at the mouth; have bloody discharge from the nose; lesions or sores on the mouth; and swollen tongues. Affected animals are often found lying in or near a water source as they attempt to lower their core body temperature. "We see more outbreaks occur during late summer and early fall (August-October) as deer gather at watering holes where the midges also tend to congregate. There is no known way to control these outbreaks other than wait for a frost to kill the midge", Pauley explained. Within two weeks of a frost, documented outbreaks often cease. If you find a carcass that seems to be infected by EHD, you can leave it where you find it or move it to a more desirable location. If it seems to have died from other unknown causes, please notify the regional office at (208) 799-5010.