November 2, 2006

Dr. Walter Cottrell, Pennsylvania Game Commission wildlife veterinarian, today announced the state Department of Health's laboratory in Lionville, Chester County, has confirmed that a fisher recovered near St. Michaels, Cambria County, was rabid. This particular fisher had become a part of the Game Commission's ongoing research project seeking to learn more about this member of the weasel family.

"This is the first recorded case of rabies in this species in Pennsylvania," said Dr. Cottrell. "Like any mammal, fishers are susceptible to rabies, but it has never been confirmed in this species before.

"With many Pennsylvanians, including hunters, trappers and hikers, preparing to enjoy outdoor activities in Penn's Woods, we wanted to remind them to be cautious if they encounter and wild animal acting in an unusual manner, and not to handle wildlife they find dead."

In July, this fisher was trapped while stealing eggs from a farm in Cambria County. After being radio collared, its apparently normal movements were periodically monitored as part of the fisher study. On Oct. 27, the animal was known to be alive. However, on Oct. 28, researchers began to receive a mortality signal from its radio collar and, on Oct. 29, it was found dead beneath a brush pile in a location where being hit by a car was a possibility.

"There was blood from multiple body orifices, but no other visible clues suggesting a cause of death," Dr. Cottrell said. "Because the cause of death was not obvious and the person who handled it did not wear gloves, Game Commission Wildlife Conservation Officer Shawn Harshaw recommended that it be submitted for rabies testing."

While awaiting the results, the fisher was transferred by another individual to Dr. Cottrell at the Animal Diagnostic Laboratory at Penn State University. The necropsy revealed extensive lung bruising and blood in the urine, but little else.

"Since the animal tested positive for rabies, no further examination of the tissues taken at necropsy will be done," Dr. Cottrell said. "The actual cause of death will not be determined. We know that the rabies virus moves relatively slowly from the site of the bite or exposure to the brain where it replicates and then migrates to the salivary glands. Only then does the animal become clinically affected and shed the rabies virus, usually by way of a bite."

Without a conclusive necropsy, Game Commission researchers will be left to wonder if this fisher was struck by a vehicle, which made him seek shelter under the brush pile, or if it was experiencing clinical rabies - the so called 'dumb' form of rabies - and seeking solitude in that brush pile.

"Even though we won't ever know, we are left with a reminder that handling wildlife - even by trained professionals - can potentially place an individual in contact with a serious disease, such as rabies."

In the past, two fishers had been tested at the state Department of Agriculture's veterinary laboratory for rabies, and both tests were negative.