Tuesday, August 26, 2008

DELAWARE NEWS: Epizootic Hemorrhagic Disease Found in Delaware Deer

The Delaware Department of Natural Resources and Environmental Control's Division of Fish & Wildlife is reassuring Delaware residents and hunters that an insect-borne disease that has been killing white-tailed deer throughout North America does not affect humans and has little long-range ramifications for the health of the state’s deer herd.

Epizootic hemorrhagic disease (EHD), also known as “blue tongue,” is the most significant disease afflicting white-tailed deer in North America but is also the best known and most widely studied, having first been identified in 1955 with regular, almost annual outbreaks since. By Delaware standards, last year was an uncommonly severe year, with 132 EHD-related deer fatalities.

“We recently received the first report of a suspected EHD deer casualty this year, so we want to begin educating hunters and the public about the disease. While the virus is often fatal, it apparently did not have much of an impact on the Delaware deer population, as the overall harvest from the 2007-2008 season was the third all-time highest. If EHD had significantly impacted the deer herd, we would have expected the harvest to be down, but we didn’t see that,” said Game Mammal Biologist Joe Rogerson.

Humans cannot be infected by EHD, nor can the disease be transmitted by consuming venison from infected animals. However, hunters are advised to avoid eating visibly sick deer because they may be stricken by a secondary infection that could affect people, Rogerson noted.

EHD is transmitted by small biting flies commonly called midges or “no-see-ums.” All known outbreaks of EHD in Delaware have occurred in late summer and early fall, and are abruptly curtailed with the onset of frost, which kills the midges and suspends the hatch of larvae. No pesticides can be sprayed to kill the insects that cause EHD, nor can white-tailed deer be vaccinated against the disease.

“We are in a position of allowing nature to run its course and waiting for a hard frost to kill the midges,” Rogerson said.

Symptoms of the disease in deer resemble another sickness, chronic wasting disease, or CWD, which is not yet known to have occurred in Delaware. Afflicted animals exhibit pronounced swelling of, and bleeding from the head, neck, tongue and eyes. Deer can die from EHD as soon as one day after contracting it, but more commonly survive for three to five days. Carcasses are often recovered near water and the EHD outbreaks are most often associated with periods of drought.

As with many viruses, not all deer will die once they are infected. Some will be able to enact an immune response and fight off the infection. These deer will then have the antibodies to ward off any potential future infections. The virus deteriorates less than 24 hours after a deer dies, and cannot be spread from carcasses. EHD does not generally have a significant impact on livestock.

Hunters or members of the public who see a deer carcass with no readily apparent cause of death are asked to report it to Game Mammal Biologist Joe Rogerson, Division of Fish & Wildlife, at 302-735-3600.

“While nothing can be done to prevent the further spread of EHD until colder weather halts the midges from infecting deer, the Division would like to document deer mortality for research and to obtain data for future references to the disease,” Rogerson said.

Source: Delmarva Now!

MICHIGAN NEWS: Chronic Wasting Disease Confirmed in Deer

A whitetail deer at a captive facility in Kent County has been confirmed to have chronic wasting disease. The fatal illness in its latter stages has symptoms similar to mad cow disease but affects only cervids like moose, elk and deer, state officials said Monday.

The Michigan Agriculture Department placed an immediate quarantine on all of the 580 captive cervid facilities in Michigan, and Becky Humphries, director of the Department of Natural Resources, said she would announce a total ban on the baiting and feeding of wild deer in the Lower Peninsula as of today.

Even before the single case was confirmed in a 3-year-old doe that was born at the Kent County facility, the state had quarantined five other deer operations in Montcalm and Osceola counties that bought deer from it or sold deer to it.

Humphries said the state's primary concern was to ensure that the disease has not spread from the captive deer to the state's wild deer herd of about 1.5 million whitetails.

DNR veterinarian Steve Schmitt said that under a chronic wasting disease plan the state wrote in 2002, a so-called hot zone was declared in the area within five miles of the infection site, including all or parts of Tyrone, Solon, Nelson, Sparta, Algoma, Courtland, Alpine, Plainfield and Cannon townships.

Testing will be required for all deer killed within that zone.

Schmitt said that even before deer hunting starts with the archery season Oct. 1, the DNR will try to test 300 deer in the hot zone that will be taken under crop damage permits or by roadkills. Another 300 will be tested in surrounding counties.

About a dozen years ago, baiting was banned in some localized areas after bovine tuberculosis was discovered in wild whitetail deer in several counties in the northeastern Lower Peninsula.

But often hunters ignored that ban, and bait continued to be sold even at the heart of the TB zone.

Biologists believed it was a only a matter of time before the wasting disease, first identified about 40 years ago in captive deer in Colorado, reached Michigan after spreading to a dozen other states in the last three years, including Wisconsin and Illinois.

Chronic wasting disease is caused by mutated proteins called prions, which cause nearby proteins to mutate. This usually happens in the brain and spinal column.

Source: Detroit Free Press