A deadly viral infection known as Adenovirus Hemorrhagic Disease (AHD) was confirmed in late August of 2017 in a mule deer herd east of Goldendale in Klickitat County and in June 2021 in the San Juan Islands.
Report sightings of live or dead deer with signs of AHD through the reporting link on WDFW’s Wildlife Diseases webpage.
This type of AHD is specific to deer and is not uncommon in other states, including Oregon, where the latest outbreak was reported near The Dalles in the Spring of 2017.
Adenoviruses belong to a small group of viruses that can infect a variety of animals, both wild and domestic. AHD in deer was first identified in California in 1994. It has been common enough in California and other western states that it likely has afflicted Washington deer in the past, but was first documented in 2017.
AHD specific to deer does not pose a risk to livestock, pets, or people – from contact or by consuming the meat. However, the use of disposable gloves is always recommended for handling any wildlife carcass.
Symptoms of AHD in deer
Signs of deer with AHD include rapid or open-mouth breathing, foaming or drooling at the mouth, diarrhea (sometimes bloody), weakness, and emaciation. Most of the dead deer reported in Washington were fawns, which is common with AHD.
Death can occur within three to five days from the time a deer is exposed to the virus, although not all infected deer die.
In California, there has been high mortality among infected fawns and lower mortality among infected adult deer. Numerous outbreaks have occurred in multiple locations across Oregon since the early 2000s. These have included all-age die-offs and other outbreaks that tend to affect more of the younger fawns. Mule deer in central Oregon and black-tailed deer along the southern coast and mid-Willamette Valley have been particularly hard-hit during outbreak years.
Cases of AHD typically peak in midsummer and taper off in the fall.
Transmission and treatment
There is no known cure or treatment for the virus.
AHD is transmitted by direct contact between deer, either through bodily fluids or possibly airborne routes. This makes it more likely for the virus to spread in areas with high deer concentrations.
To minimize the spread, feed or water should not be provided in order to avoid concentrating deer.