Reported Rabies Cases On the Rise in 2006

CHRIS TORRES
Staff Writer

The number of reported rabies cases in the Mid-Atlantic increased in 2006, with Pennsylvania recording its highest total in 15 years.

According to the Pennsylvania Department of Agriculture (PDA), the number of reported rabies cases rose to 505 in 2006, up from 406 in 2005 and higher than the previous high of 490 in 2002.

Last year’s total was the highest since 1990, when 611 reported cases were recorded in the commonwealth.

Maryland, New Jersey and New York also reported an increase in cases.
Virginia saw the biggest surge in reported cases, 637, up from 495 in 2005. The Virginia Department of Health Office of Epidemiology reports there were 30 reported cases between Jan. 1 and 27, ahead of last year’s pace that saw 14 reported cases during the same time period.

Most positive tests came from raccoons that were either found dead and tested for the disease or were euthanized to be tested after a suspected run-in with a human being.

Raccoons are the biggest carrier of the disease on the East Coast. On its Website, PDA states the disease has reached an “epidemic” level in the animal. Skunks and bats also had a high number of positive cases.

Reported cases of rabies in livestock was quite low, with states averaging about six or seven cows and sheep testing positive.

According to the Centers for Disease Control (CDC), rabies is a disease that attacks the central nervous system. It can cause insomnia, anxiety, confusion and slight or partial paralysis in its latter stages. There is no known cure for the disease once neurological symptoms start appearing. CDC estimates a person will die within days of the appearance of neurological symptoms.

A series of shots, usually about six or so, is given to someone that has been bitten by an animal testing positive for the disease. CDC said it takes about a month for the disease to incubate in an animal or human.

Lola Russell, CDC spokesperson, said of the 40,000 people in the U.S. exposed to the disease in 2006, three of them died with the last one being in November. Russell said rabies kills about 55,000 people worldwide each year with most deaths occurring in Africa and Asia.

Officials state they have no clear reasons for why reported cases have increased over the last few years.

Dr. Julia Murphy, a public health veterinarian with the Virginia Department of Health, said the spike in reported cases in Virginia may be due to the increased urbanization of once rural areas as well as the increasing number of “potential” exposures being reported.

Murphy said state officials only test animals when there is a potential exposure reported by someone in contact with a rabid animal or someone in the medical field that suspects they have a patient that was bitten by a rabid animal.

When the suspected animal is caught, it is euthanized and samples are taken from its brain.

Most of the reported cases in Virginia were in urban areas, where animals and humans constantly come in contact with each other. Fairfax, Loudoun and Prince William counties, all of which sit in the Washington, D.C. metropolitan area, had the largest number of reported cases.

The same can be said of Maryland, where heavily populated Montgomery County had the highest number of reported cases; Pennsylvania, where Chester and Bucks in the Philadelphia area, and Westmoreland and Allegheny counties in the Pittsburgh area had the largest number of cases; and New York, where Westchester County in suburban New York City had the highest number of reported cases.

“Wherever you have a lot of people, there is a greater potential for them to come into contact with wildlife,” Murphy said.

Murphy said another potential factor in increased cases is what she called a normal cycling of the disease in specific types of animals. “There can be a number of factors,” to the disease potentially spreading, Murphy said.

Most states require domestic dogs and cats to be immunized against rabies when they are less than a year old.

Wild animals are a different story.

Dennis Slate, national coordinator of the rabies program with USDA Wildlife Services, said there is no clear way of knowing just how many wild animals have rabies since most states only test animals after a bite or if they are already dead.

Through increased surveillance and inoculation programs, Slate hopes the disease will at least be prevented from spreading to other parts of the country.

Since 2003, Wildlife Services has administered an inoculation and surveillance program which Slate said is focused on vaccinating as many wild raccoons as possible in any given year to prevent the disease from moving west.

Fifteen states from New Hampshire to Florida participate in the program, which Slate said is designed to keep the disease from spreading through dropping vaccines into areas buffered by large lakes and rivers.

The program works as a plane, flying at about 500 feet, drops vaccines wrapped in an “outer bait matrix” made of fishmeal into target areas. Slate said the vaccine is the only “licensed” rabies vaccine in the U.S.

A raccoon bites into the matrix and swallows the vaccine. Slate said 180 baits are dropped per square mile during the late summer and early fall, when female raccoons give birth. Each bait is designed for a single raccoon.

Another separate program in Texas is designed to control the spread of rabies in coyotes.

Slate estimates 1.5 million baits were dropped in Pennsylvania in 2006, largely along the state’s western border with Ohio. Over 11 million baits were dispersed nationwide.

But the program has been slow to show progress. In Ohio for example, Slate said rabies cases were reported outside of target areas where they should have been buffered out. In Virginia and West Virginia, the zones have each been moved farther east, but only by five miles. “It’s been a little give and take,” Slate said. “We continue to hope to move it (rabies) eastward, but it’s a slow process.”

Another program involves outraging raccoons to do research on where the population is moving.

According to an article written in the (Johnstown) Tribune Democrat, workers from the Bolivar, Pa. office of Wildlife Services have been trapping raccoons in Somerset and Westmoreland counties and fitting the animals with radio collars. A tooth is extracted from a trapped raccoon and a blood sample is taken. The sample gives information on whether the animal has ingested any rabies vaccine, how long ago it was ingested and how many baits it ate. Using GPS coordinates, workers track the movements of the tagged animals in their natural habitats.

The article states the program started out with 32 raccoons being eartagged last summer. But the number is now down to a dozen because of “unexplained” disappearances of some of the animals.

This spring, workers in the region will implant radios on the abdomens of raccoons for better tracking.

While the vaccine is specifically designed for raccoons, other animals can ingest it and it can be effective. But Slate said he has yet to see evidence the vaccine is effective in skunks. Along with raccoons, skunks have some of the highest number of positive rabies tests. Slate said spilling of the vaccine when bitten into may be a reason for its ineffectiveness.

There is also a concern when it comes to other animals getting the disease, such as coyotes and bats. Two coyotes were reported testing positive for the disease in Pennsylvania in 2006, the first time that has ever been recorded.

Bats also carry the disease in large numbers. But unlike other animals where a bite would be painful, a bat’s small mouth and teeth biting into human flesh can be virtually unnoticeable. Slate said most human rabies deaths are a result of being bitten by bats. “With bats, certainly a person is at risk,” he said.