Signs of the disease in deer include: high fever, lack of appetite, respiratory distress and edema of the head and neck. There is congestion of the mucosal surfaces of the mouth along with ulcers and erosions of the tongue, palate, rumen and abomasum.
The incubation period (time from exposure or infection to clinical disease) is thought to be from five to 10 days, and animals may die within two days of initial clinical signs.
Mortality rate of the acute form is high, although a chronic form also occurs in which recovery may take several weeks. The disease is endemic in the deer population, meaning there are carrier animals and when the insect vector is present, the virus will be transmitted to susceptible animals.
EHD in cattle is primarily non-clinical, meaning that the animal is infected but does not show clinical signs of illness. In severe cases however, similar clinical signs found in wildlife may be present in cattle.
Cattle may be lame and off feed with excess salivation due primarily to erosions and ulcers in the mouth, accompanied with cracking of the skin of the muzzle.
Cases also have been reported in elk and bison but rarely in sheep. Currently, goats do not appear to be susceptible, says Stokka.
Other disease considerations that may be similar in clinical presentations are bluetongue, vesicular stomatitis, malignant catarrhal fever, and foot and mouth disease. This is the reason oral symptoms and signs are considered significant in diagnosing this disease.
Though the EHD virus is not a risk to human health, as there is no evidence that the EHD virus infects humans, under no circumstances should deer exhibiting signs of illness be harvested for consumption, warns Stokka.
Source : ndsu.edu