Less serious than Chronic Wasting Disease, but nevertheless Pennsylvania Game Commission staff and board of commissioner members expressed concern at this month's final quarterly meeting of the year were the test results from a wild deer that confirmed that Epizootic Hemorrhagic Disease has been found in Northampton County.
A test sample from the wild deer was collected August 18, and EHD also has been confirmed in captive deer in Northampton County in the vicinity of the wild deer. In addition, one captive deer in Erie County was confirmed to have died of EHD, based on a sample collected August 13.
EHD is a common, but sporadic, disease in whitetail deer populations most common in the Southern United States and is contracted by the bite of insects called "biting midges." In more Northern states, such as Pennsylvania, EHD occurs less often and affected deer are less likely to mount an effective immune response, and PGC officials midges may have been carried north by storms.
Meanwhile, the board gave final approval to revised emergency powers that would allow the PGC executive director to take actions that will mitigate risk factors and determine the prevalence and geographic distribution of CWD if discovered within the state. Revising and upgrading the plan that had been effect had been proposed by the board at its June meeting.
Once a deer has been infected, the virus usually kills the deer within 5-10 days, and there is no evidence that humans are at risk from EHD, but other diseases could be transmitted by careless hygiene when processing deer. EHD is not spread from deer to deer by contact, and deer displaying severe symptoms of EHD are usually not suitable for consumption because of the rapid deterioration of the meat and secondary bacterial infection.
Although some EHD symptoms are similar to those of CWD such as excessive drooling, weakness and a loss of fear of humans there is no relationship between the two diseases. Because these diseases coexist, however, deer submitted for EHD testing also are being tested for CWD.
EHD is one of those diseases in which the mortality rate can be amplified by anything that serves to congregate deer, such as supplemental feeding, and placement of salt or mineral blocks. While the disease is not spread through deer-to-deer contact, congregating animals through feeding does make transmission easier by allowing midges that carry the virus greater access to a larger number of animals in a more confined area, therefore, such feeding activities should be discontinued immediately.
In 1996, EHD was suspected to be the cause of death in nearly 25 deer in Adams County, but test results in that case were inconclusive. Other outbreaks in Pennsylvania were confirmed in 2002 and 2007.
First identified in 1967, CWD is a transmissible spongiform encephalopathy that affects cervids, including all species of deer, elk and moose, and is a progressive and always fatal disease of the nervous system. Scientists theorize CWD is caused by an agent called a prion that is capable of transforming normal brain proteins into an abnormal form, in turn causing the death of brain cells.
Prions are present in and shed into the environment by infected animals through blood, urine, saliva and tissue of the central nervous system. As a result of CWD being discovered early this year less than 10 miles south of the Mason-Dixon Line in Maryland, the PGC board put the plan for the revised emergency authority on the fast track.
Under the emergency authority, if the executive director concludes the spread of CWD poses a threat within or adjacent to Pennsylvania, he will have the emergency authority to prohibit the importation of high-risk cervid parts from areas that are known to harbor CWD and define and designate Disease Management Areas in the state. Once a DMA is designated, the executive director can use his emergency authority to take several actions.
These action include, but are not limited to, allowing the taking of cervids without regard to established seasons and bag limits and methods of take; requiring mandatory checking of hunter-killed cervids; prohibiting the removal of high-risk cervid parts; prohibiting the rehabilitation of cervids; prohibiting the use and possession of cervid urine-based attractants; prohibiting the feeding of cervids; and prohibiting any new permits to possess or transport live cervids.
"For more than a decade, the Game Commission has been monitoring our CWD status and striving to prevent CWD from coming to our state," PGC executive director Carl Roe said. "While I hope that I never have to use these new tools, it is imperative this agency's executive director be empowered to contain the disease to one area and prevent, or at the very least, slow the spread of this disease."
Not effected by the change in regulations will be captive cervid operations, which are under the jurisdiction of the Pennsylvania Department of Agriculture. In such situations, it will be unlawful for any person to violate any provision of an executive order issued by the PGC executive director.
At the present time, there is neither a practical way to test live animals for CWD, nor is there a vaccine. Clinical signs include poor posture, lowered head and ears, uncoordinated movement, rough-hair coat, weight loss, increased thirst, excessive drooling and, ultimately, death.
Research by the Center for Disease Control has determined there is no scientific evidence that CWD has or can spread to humans by either contact with infected animals or by eating meat of infected animals. According to the CDC, the risk of infection with the CWD agent among hunters is extremely small, if it exists at all and it is extremely unlikely that CWD would be a food-borne hazard.
More information about CWD and the state's CWD-prevention plan and EHD is available on the PGC website at www.pgc.state.pa.us