FOR RELEASE: Aug. 20, 1997
Contact: Roger Segelken
Office: (607) 255-9736
Internet: [email protected]
Compuserve: Larry Bernard 72650,565
http://www.news.cornell.edu
ITHACA, N.Y. -- The northward spread of raccoon rabies can be halted by
vaccination barrier zones, veterinarians and wildlife biologists at the
Cornell University College of Veterinary Medicine are predicting.
A preliminary assessment of vaccine trials in New York, Vermont and Ohio,
where oral vaccines are dropped from aircraft into raccoon rabies-free
areas, points to the barrier zone strategy as the most promising way to
prevent further spread of the disease, the Cornell experts say. But the
vaccination barrier should be extended across northern New Hampshire and
Maine, they recommend, before treating East Coast states that already are
infected with wildlife rabies.
"The vaccination barriers appear to be holding," said Donald H. Lein,
D.V.M., Ph.D., director of the Diagnostic Laboratory at the Cornell
University College of Veterinary Medicine, where the anti-rabies campaign
for the Northeast is based. "We're ready to establish the same kind of
barriers in Maine and New Hampshire. This problem calls for a regional
approach, because sick raccoons don't stop at state lines."
Or at international borders, either. That's why Ontario and other Canadian
provinces are interested in aiding the U.S. anti-rabies effort, said Laura
L. Bigler, Ph.D., coordinator of the Cornell vaccination program. A
parallel effort to vaccinate Canadian foxes has all but eliminated fox
rabies from southern Ontario, Bigler reported. Ontario and Quebec have
provided financial and in-kind assistance to the Cornell project in hopes
of keeping raccoon rabies from spreading across the U.S.-Canada border and
infecting Canadian raccoons.
The Cornell wildlife rabies control program uses an oral rabies vaccine,
Raboral, that was fully approved earlier this year by the U.S. Department
of Agriculture's Center for Veterinary Biologics. Capsules of the vaccine
are concealed in flavored baits that are dropped from aircraft or
distributed by hand in populated areas. Besides raccoons, the same vaccine
has been shown to control rabies in coyotes as well as red and gray foxes.
Cooperation of several federal, state, county and provincial agencies was
required to initiate the rabies-control programs in strategic regions of
New York and Vermont. Beginning in 1995, Cornell developed a regional
rabies-control strategy for raccoons in the Northeastern United States.
A vaccination zone also has been established in Ohio, said Bigler, who
assisted the effort in that state. "But additional zones are required in
Maine and New Hampshire to complete the barrier strategy. Then we can
begin the second phase, gradually moving the vaccination zones southward
into infected areas to attempt to eliminate this disease altogether," she
said.
Raccoon rabies was first diagnosed in the United States in Florida in 1947.
The viral disease made a great leap northward in the late 1970s, when an
estimated 3,500 raccoons were transported from Florida to Virginia. Since
then, raccoon rabies has spread to parts of every eastern state, from Maine
to Florida.
Although coyote rabies is found in Mexico and fox rabies occurs in Canada,
neither country has reported the raccoon variant of rabies, Bigler noted,
and the Appalachian Mountains serve as a natural barrier to contain raccoon
rabies to the East. Consequently, the elimination of raccoon rabies from a
relatively small area, the East, may be possible with vaccination, she said.
Compared with the cost of treating rabies in the United States, an
estimated $200 million to $1 billion a year, the cost of preventing raccoon
rabies is much less but it is not inconsequential, Lein said.
"The vaccine baits are expensive. That's why we're fine-tuning our program
by using the smallest possible number of baits per square mile and
vaccinating annually, in the fall instead of twice a year to keep the
overall costs as low as possible. We also need to test different baits to
see if there are any 'raccoon favorites,' while also collecting information
about how far apart the baits can be placed. In the long run, we predict
that a coordinated, unified program to eliminate raccoon rabies will be
much less expensive than individual state and provincial initiatives that
are performed in isolation," Lein said.
Lein, the Cornell Diagnostic Laboratory director, called for congressional
action to appropriate federal funds through the Animal Damage Control unit
of the USDA's Animal and Plant Health Inspection Service (APHIS). That
unit, in cooperation with USDA Veterinary Services, universities, producer
organizations, federal and state agencies, already administers eradication
programs for other diseases that impact people, domestic animals and
wildlife, such as brucellosis, tuberculosis and pseudorabies, Lein observed.
"USDA-APHIS-ADC should be granted the authorization and fiscal resources to
proceed to carry out their mandate to control this disease with
established, coordinated programs such as the Cornell control program for
raccoon rabies," Lein said. "Vaccination of wildlife will protect people,
pets and livestock from this fatal disease."
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