Small packets of fishmeal bait containing a rabies vaccine are to be dropped from a helicopter Thursday over parts of Nassau County and New York City to inoculate raccoons against the viral disease.

The aerial program is coordinated by Cornell University in cooperation with local health agencies and the U.S. Department of Agriculture to prevent the eastward spread of rabies by raccoons into Nassau and Suffolk counties. The program, which also targets raccoons in Brooklyn, Queens and Staten Island, is in its fourth year of vaccinating raccoons there.

Statewide, rabies primarily occurs in raccoons, bats and skunks, experts said Wednesday.

Wild raccoons become immunized against rabies when they bite into the bait, a scented, brown, rectangular packet with a pink fluid inside — the vaccine. The sachet is about the size of a ketchup packet and the vaccine, known as RABORAL V-RG, is federally licensed.

“There is a fish attractant on the bait,” said Cornell wildlife biologist Laura Bigler, who is leading the massive field campaign to vaccinate wild raccoons.

“It’s hard to say how many raccoons there are,” Bigler said when asked to estimate the animals’ population size, but thousands of packets are being airdropped with the hope of preventing rabies in the furry creatures living in the metropolitan region.

She said a similar vaccination strategy has helped immunize skunks against rabies. Scientists, however, have yet to design a vaccine distribution method to immunize bats, Bigler said.

Though Bigler emphasized that a large concentration of raccoons inhabit northern Nassau County, the vaccine program targets the southwestern portion of the Town of Hempstead. Aerial vaccine drops over Nassau had been scheduled for Wednesday, but were canceled because of rain. Weather permitting, a low-flying USDA chopper is to conduct the mission Thursday and Friday.

“Nassau County is supportive of all state and federal efforts to control the spread of raccoon rabies,” said Mary Ellen Laurain, spokeswoman for the Nassau County Department of Health. Her agency vaccinates the raccoon population as well, distributing the vaccine by hand in areas known to be their habitats, she added.

The New York City Department of Health noted in a statement Wednesday that the USDA chopper will target a distribution area that includes woods, bushes, streambeds and sewers, among other areas. Baits will not be dropped in dense residential areas, roadways, parking lots or open fields. Flights begin Thursday and run through Tuesday, between the hours of 8 a.m. and 8 p.m.

advertisement | advertise on newsday

Rabies, a deadly infectious disease, is caused by a virus that zeros in on the central nervous system. It is often carried by wild animals, such as raccoons, but is also common among skunks, coyotes, bats and foxes. Unvaccinated pets and livestock can be infected if bitten by a rabid wild animal.