petnews
July 18th, 2004, 06:57 AM
By MEREDITH GOAD, Portland Press Herald Writer
An experimental program that dropped almost 300,000 doses of raccoon rabies vaccine over three Maine counties last summer is showing promising results, according to the biologist in charge of the project.
Laura Bigler, a Cornell University wildlife biologist, said blood samples drawn from raccoons in Penobscot, Aroostook and Washington counties show that 70 to 80 percent of the raccoons tested ate the fishmeal bait laced with vaccine and have developed antibodies to the rabies virus.
Adding to the optimism is the fact that biologists who have been searching for animals that are sick or acting strangely in the vaccine drop zone have been unable to find any, Bigler said.
"We set up the vaccination zone just north of where we knew rabies cases were occurring, knowing that surveillance is not very good in that part of the state because there are very few people living there," Bigler said. "We're continuing to see cases south of the zone, but not in the zone and certainly not north of it."
The project is part of a national effort to stop the spread of raccoon rabies, a fatal disease that has spread rapidly in Maine's wildlife population since the mid-1990s. People who are exposed to the rabies virus through contact with infected wildlife or pets must undergo a series of inoculations that can cost as much as $3,000.
Last year there were 72 reported cases of animal rabies in Maine, though the virus has probably infected many more animals.
"The idea with these oral rabies vaccination projects is to try to stop the progress of the disease in whatever direction you're trying to stop it, and then try to move it back," said Don Hoenig, the state veterinarian.
Bigler is hoping to drop more vaccine in late August or early September in the same towns that received it last year. She is still waiting to hear if the U.S. Department of Agriculture plans to fund the effort with a $400,000 grant.
"I hope to know any day now," she said.
Last year the project received most of its funding from the Canadian Food Inspection Agency, which contributed $270,000. Rabies is not yet a major public health issue in Canada, so there is a lot of interest in stopping the disease before it reaches the border.
But the Canadians have had their hands full with avian influenza and other issues, Bigler said, "and as much as they want to contribute money this year, they don't have it in their budget."
The Maine project is being done in cooperation with New Brunswick, which has its own wildlife vaccine program that will be continued this year, Bigler said.
Biologists will have a better idea of just how effective last year's bait drop was in Maine after lab results come back on more than 100 raccoon teeth that will serve as indicators of immunity.
Last year, after distributing the bait, researchers spent six weeks live-trapping raccoons to collect blood and tooth samples for testing. The bait contained tetracycline, which acts as a biomarker that creates a fluorescent stain on teeth. If the stain shows up on a tooth, it means that animal consumed the vaccine.
Only one laboratory in the United States and one in Canada do this type of testing, however, so getting the results back is taking some time.
"The biomarkers give us a better indication of what proportion of the population encountered baits," Bigler said.
An experimental program that dropped almost 300,000 doses of raccoon rabies vaccine over three Maine counties last summer is showing promising results, according to the biologist in charge of the project.
Laura Bigler, a Cornell University wildlife biologist, said blood samples drawn from raccoons in Penobscot, Aroostook and Washington counties show that 70 to 80 percent of the raccoons tested ate the fishmeal bait laced with vaccine and have developed antibodies to the rabies virus.
Adding to the optimism is the fact that biologists who have been searching for animals that are sick or acting strangely in the vaccine drop zone have been unable to find any, Bigler said.
"We set up the vaccination zone just north of where we knew rabies cases were occurring, knowing that surveillance is not very good in that part of the state because there are very few people living there," Bigler said. "We're continuing to see cases south of the zone, but not in the zone and certainly not north of it."
The project is part of a national effort to stop the spread of raccoon rabies, a fatal disease that has spread rapidly in Maine's wildlife population since the mid-1990s. People who are exposed to the rabies virus through contact with infected wildlife or pets must undergo a series of inoculations that can cost as much as $3,000.
Last year there were 72 reported cases of animal rabies in Maine, though the virus has probably infected many more animals.
"The idea with these oral rabies vaccination projects is to try to stop the progress of the disease in whatever direction you're trying to stop it, and then try to move it back," said Don Hoenig, the state veterinarian.
Bigler is hoping to drop more vaccine in late August or early September in the same towns that received it last year. She is still waiting to hear if the U.S. Department of Agriculture plans to fund the effort with a $400,000 grant.
"I hope to know any day now," she said.
Last year the project received most of its funding from the Canadian Food Inspection Agency, which contributed $270,000. Rabies is not yet a major public health issue in Canada, so there is a lot of interest in stopping the disease before it reaches the border.
But the Canadians have had their hands full with avian influenza and other issues, Bigler said, "and as much as they want to contribute money this year, they don't have it in their budget."
The Maine project is being done in cooperation with New Brunswick, which has its own wildlife vaccine program that will be continued this year, Bigler said.
Biologists will have a better idea of just how effective last year's bait drop was in Maine after lab results come back on more than 100 raccoon teeth that will serve as indicators of immunity.
Last year, after distributing the bait, researchers spent six weeks live-trapping raccoons to collect blood and tooth samples for testing. The bait contained tetracycline, which acts as a biomarker that creates a fluorescent stain on teeth. If the stain shows up on a tooth, it means that animal consumed the vaccine.
Only one laboratory in the United States and one in Canada do this type of testing, however, so getting the results back is taking some time.
"The biomarkers give us a better indication of what proportion of the population encountered baits," Bigler said.