By Robert Lucke
Scores of white-tail deer and a few antelope and mule deer are dying in northern Montana after being bitten by a small gnat, said Shane Reno, local warden for Montana Fish, Wildlife and Parks.
The disease, which is called epizootic hemorrhagic disease or EHD, has been found in both Hill and Blaine counties. It is spread through the bite of gnats and kills within 10 to 12 hours after causing rapid hemorrhaging and shock.
"It is starting to creep this way," Reno said. "It generally starts in the east and makes its way this direction. It will continue to kill until we have a hard frost."
Locally, it has been seen in the north of Havre country, along the Milk River Valley, and as far up Beaver Creek as the experiment station.
Montana Fish, Wildlife and Parks has issued information regarding this disease.
"Hemorrhagic disease occurs frequently, but its severity and distribution are highly variable. Past occurrences have ranged from a few scattered mild cases to dramatic outbreaks. Death losses during outbreaks usually are well below 25 percent of the population but in a few instances have been 50 percent or more. To date there has not been a deer population wiped out by hemorrhagic disease."
Are livestock affected?
"In contrast to the significance of EHD and bluetongue viruses to white-tailed deer, the importance of these agents to domestic livestock is more difficult to access. Most bluetongue virus infections in cattle are silent; however, a small percentage of animals can develop lameness, sore mouths, and reproductive problems. Cattle can be short-term bluetongue virus carriers. Less is known about EHD virus in cattle. EHD virus has been isolated from sick cattle, and surveys have shown that cattle often have antibodies to this virus, indicating frequent exposure. For domestic sheep the situation is more straightforward. Sheep are generally unaffected by EHD, but bluetongue can be a serious disease similar to that in deer."
Was the outbreak caused by overpopulation?
"High density deer herds may have higher mortality rates; however, the relationship of deer density to the severity of hemorrhagic disease is not clear-cut. The number of deer that are immune, the virulence of the infecting virus, the number of livestock nearby, or the abundance of midge vectors may influence the outcome of infection within a deer population regardless of herd density. However, dense deer herds would be expected to support virus spread better than sparse herds."
Can people become infected?
"Humans are not at risk by handling infected deer, eating venison from infected deer, or being bitten by infected Culicoides vectors. Deer that develop bacterial infections or abscesses secondary to hemorrhagic disease may not be suitable for consumption."
Now here's some advice from Montana Fish, Wildlife and Parks.
"Although die-offs of white-tails due to hemorrhagic disease often cause alarm, past experiences have shown that mortality will not totally decimate local deer populations and that the outbreak will be curtailed by the onset of cold weather. Livestock owners who suspect EHD or bluetongue virus infections should seek veterinary supportive care for their animals."
