EHD is a viral infection. There are 4 predominant strains of virus, two of EHD and two Bluetongue. These are designated EHD1, EHD2, BTV1 and BTV10. There is no known cross-protection from one virus to another and that includes the same families i.e., overcoming an infection with EHD1 doesn't cross-protect against EHD2 or BTV. There have been outbreaks involving other strains but these are the predominant. It was thought for many years that recovery for EHD2 was more common and that EHD1 was the main culprit, but more recent result show that it may be equal. Infections hit the wild whitetail populations with much the same veracity that they do farmed whitetails. Native animals are just as susceptible as farmed deer if the strain is different than what is common to the geographic area.

EHD signs and symptoms 
Pyrexia is the first visible sign. As the disease progresses the animal will lose its appetite and wariness. Edema or swelling of the head and neck will occur. The victim becomes dehydrated and weakens with increased respiration, heartbeat, and salivates excessively. As the disease progresses further, ulceration of the dental pad and tongue occurs and will eventually pass blood from both ends. In prolonged cases or those surviving, sloughing of the hooves may occur. In most cases, whitetails die within 48-72 hours after being infected.

Solutions
 It appears there is little hope for a cure and curtailment of the disease comes only after a hard freeze, killing the biting insect. Deer surviving the virus build up antibodies, insulating them from another outbreak. There are some "anti-viral" drugs that might be tried in hemorrhagic disease infections such as interferon, interleukins and other immune stiumulants. There is conjecture that some of the same class drugs as those used to combat and shorten human flu like virus infections may have merit in HD infections. Anything that could help limit the weakening of host defense mechanisms (such as parasite prevention, good nutrition and stress minimization) should help reduce impact of outbreaks. Also, limiting the total exposure may have real merit i.e., there is evidence that total viral exposure is very important in mortality and even morbidity of the disease.

It makes little sense that antibiotics would have effect on a viral disease, however, they can't hurt and may reduce deadly secondary infection in recovering animals! Try LA200 as well and probably B vitamins and anti-inflammatory drugs. Fluid therapy with colloidal products would likely be lifesaving if administered at the appropriate time. Ultimately, this is a vascular disease that causes widespread hemorrhage and disseminated intravascular coagulation (DIC). The DIC is most often the cause of death.

Vector control may be the most neglected form of control. It has been determined that salinity of standing puddles may reduce the reproduction rate of the black fly (culicoides varipennis is the main culprit, although others may be more involved in BTV) thus reducing the intensity of outbreaks. Remember there may be relationship between total viral particle exposure and death rate. Spraying stock and even standing puddles in the August to November period may have merit.

In the long run, this disease takes no prisoners. It may spare you this year, next year, or even several years in a row. But if you're in black fly country, eventually it's going hit. When it does, it is capable of causing many deaths, no matter what you do.

Ultimately, we need a vaccine. In order to produce a multivalent (multiple viral strain) vaccine, we have to attract the attention of a major biological producer such as Pfizer or Ft Dodge. To give you some understanding, it would likely cost upwards of $25M to produce a vaccine according to my sources, and that's if it can be produced. We don't want a vaccine that isn't proven. Pharmaceutical companies won't produce vaccines until they are sure they have a market to recover the development and testing costs. Maybe it's time to show them that this market exists.