Idaho Fish and Game received a positive detection for bluetongue — a virus transmitted by gnats that is similar to Epizootic Hemorrhagic Disease (EHD) — in a yearling, male mule deer collected west of Homedale along the Snake River. The carcass was collected March 12 after a landowner reported seeing three dead deer.
Fish and Game was able to recover and necropsy two of the animals, and both necropsies presented findings of a hemorrhagic disease. However, samples from only one deer resulted in a positive detection of a hemorrhagic disease, specifically bluetongue.
Bluetongue is transmitted the same way as EHD and both are classified as hemorrhagic diseases. Both have been documented in most areas of Idaho, and occur sporadically in most years. The diseases more commonly affect Idaho’s white-tailed deer herds, including recent large outbreaks of EHD in white-tailed deer in the Clearwater Region. Bluetongue is less common than EHD, but it is found in livestock throughout the Great Basin, although it is rarely fatal to livestock due to blue tongue virus vaccinations, according to Nicole Walrath, Fish and Game's state wildlife veterinarian.
Neither bluetongue nor EHD pose a threat to humans. Gnats transport the viruses from animal to animal. Outbreaks become more severe during hot, dry summers when animals congregate around water sources with muddy shorelines that are prime breeding ground for gnats.
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, sometimes blue-tinged tongues.
The disease often kills deer so quickly – within a day or two – they may still be in very good body condition. In other cases, they may not die, just become sick and stop eating, resulting in poor body condition.
"Fish and Game has not had any additional reports of mortality events since March 12, which indicates that this event was localized and didn't last long on the landscape," said Regional Wildlife Manager Ryan Walrath. "However, we encourage the public to report any potential wildlife health concerns, which helps us monitor wildlife health."
The health of Idaho's free-ranging wildlife is an ongoing emphasis for Fish and Game. Reports from the public of wildlife appearing sick or dead helps Fish and Game monitor wildlife health. People can let Fish and Game know about out-of-the-ordinary conditions with animals they harvest or observe by using the online reporting form on Fish and Game's Wildlife Health page.