Hemorrhagic diseases (Epizootic Hemorrhagic Disease or Bluetongue) are common viral diseases of deer. Both viruses are related and have very similar symptoms but are different in that white-tailed deer get EHD, while Bluetongue is a well-known disease of domestic sheep, cattle, and goats, in addition to affecting deer. EHD/Bluetongue are completely separate diseases from Chronic Wasting Disease (CWD).
Signs of illness
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 emaciation.
Other wildlife, like mule deer, elk, and bighorn sheep could be exposed to the disease but are usually not stricken like white-tailed deer.
Occurrence and spread
These diseases occur during the driest part of the year when conditions are favorable for the biting Culicoides gnats that transmit them. The gnats are found in wet, muddy areas where deer may congregate during late summer and early fall, especially in unusually warm, dry years.
The spread of these diseases is usually cut short with colder, wetter weather which spreads the deer out and away from gnat-infested areas; or by the first hard frost, which kills the disease-carrying gnats. Since the incubation period for these diseases is five to 10 days, afflicted deer may be observed for a couple of weeks after the first hard frost of fall.
Domestic livestock may also be bitten by the disease-carrying gnats. Cattle and sheep are seldom seriously affected by EHD, although sheep can be quite susceptible to Bluetongue.
Because the incubation period for these diseases is five to 10 days, afflicted deer may be observed for a couple of weeks after the first hard frost of fall.
Humans are not affected by either the EHD or Bluetongue viruses. However, WDFW recommends hunters avoid shooting and consuming animals that are obviously sick.
What can be done to prevent EHD/Bluetongue?
Currently, there is no treatment for animals infected with EHD or Bluetongue. While it is understandable that people want to help, putting out food or fresh water sources for wildlife often causes additional problems such as habituating wildlife to humans, and concentrating them in areas where they can attract predators, be hit by vehicles, or transmit disease to each other.
Private property owners are encouraged to dispose of carcass onsite via burial or leave for scavengers if viable. If onsite disposal is not an option you can dispose of the carcasses at a licensed landfill (not all landfills and transfer stations provide this service so contact your area facility first). Also give your regional WDFW office a heads up that you will be transporting a carcass to a disposal facility as it is illegal to transport wildlife under certain circumstances. In some areas, you can dispose of carcasses in your regular trash. Check with your local solid waste service provider. Also check for rendering options in your area. These methods of removal pose no risk to humans.
While having the carcass of an animal killed by EHD or Bluetongue on private property is not desirable, WDFW does not have resources to remove them and we ask for the public’s help.
Hunting Season Impacts
No further reductions in the white tailed deer seasons are planned at this time. Given the relatively large hemorrhagic disease outbreak in 2021, it is anticipated that hunters could be challenged to find deer to harvest in some area over the next few years.