This month planes have been flying low over the forest of Northern New England, pelting the ground with hundreds of thousands of fish-flavored treats.
Their target: raccoons.
The fishy treats are laced with rabies vaccine.
The vaccine bait drops are part of a government strategy to halt the march of raccoon rabies across the Eastern United States.
So far the program has helped stall the northward advance in New Hampshire at the North Country.
But in southern New Hampshire the virus is well established and rabies cases are on the rise.
New Hampshire Public Radio’s Kerry Grens reports.
…sounds of plane propellers turning off…
It’s about nine thirty in the morning, and a black and yellow DeHavilland with twin propellers rolls to a stop at Newport Aiport in Vermont.
Several biologists hop out of the plane, after their first round of dropping bait on the Vermont countryside.
A DeHavilland twin otter airplane, owned by the Ontario Ministry of Natural Resources, returns to Newport Airport after a flight over the Connecticut River Valley . (Kerry Grens, NHPR)
The plane had left a seven AM, and has about five more flights scheduled for the day.
Hale [bob—flight 303 description]: This flight here on 303 was 2.6 hours and they dropped 31,000 baits.
Bob Hale runs the vaccine baiting program for the US Department of Agriculture.
Over several days four hundred thousand tasty vaccine snacks will fall on New Hampshire and Vermont.
They look like catchup packets, coated with a brown goo.
Hale [hale—vaccine description]: It’s a fish meal polymer—crawfish, whitefish all ground up—and then the vaccine is inside.
Inside the planes, the packets are loaded on to a conveyer belt, which leads down to an opening in the belly of the plane.
Biologist Andrew Silver from the Ontario Ministry of Natural Resources demonstrates how the plane's conveyor belt delivers the fish-flavored vaccine bait to an opening in the plane's belly. (Kerry Grens, NHPR)
Biologist Libby Kempf has just returned from the first flight of the day.
The weather has been ideal.
Kempf: The valleys they had low clouds sitting in the valleys, I’ve never seen that before. It’s pretty neat. And when you’re flying over these areas you have to turn the machine off because you don’t know what’s underneath. If there’s a kiddie pool or something you don’t want to drop a bait in there.
The planes skim the countryside at 500 feet—Kempf says it’s easy to identify what’s below and avoid the places where people live.
In New Hampshire the flights are concentrated along the Connecticut River, from Stewartstown south to Lancaster.
Raccoon rabies has not invaded this area of the state, and the USDA’s strategy is to fortify an immune barrier to halt the virus’s spread from the south.
The approach has been effective.
Each year after the drop John McConnell’s team from the USDA traps raccoons and tests them to see how many have eaten the baits.
McConnell [john—30 percent vaccination]: We’re finding that anywhere between 30 and 35 percent of the animals have consumed a bait and are vaccinated against rabies.
So far, the immunity barrier seems to be holding.
Dennis Slate at the USDA runs the rabies management program from his office in Concord.
Biologists wait for the plane to fuel before they go out on another vaccine drop. (Kerry Grens, NHPR)
Slate wishes he could push back the advance of the disease.
Slate [slate—prevalent in s nh move border down]: Rabies is prevalent here in southern New Hampshire. Of course the long term goal would be to move south, into this zone. But oral vaccination is quite expensive and we have to use our resources strategically.
Slate oversees the oral rabies vaccination program in seventeen states.
In total, it costs about twenty million dollars each year.
Which might sound like a lot, but the annual public health cost attributed to rabies for all of the United States is about three hundred million, according to the Centers for Disease Control.
The CDC says about forty thousand people each year get rabies shots after potentially being exposed.
In New Hampshire rabies cases in animals are up this year.
Wikoff [peter—pos animals this year]: Got in mostly raccoons, skunks, foxes, and we’ve actually had a couple of positive cats this year. We’ve done some strain typing on those and they’ve all been the raccoon strain.
That’s Peter Wikoff at the state’s public health laboratories.
The strain of rabies—whether raccoon, fox, or bat—is named for the animal that carries it most often.
The raccoon strain is currently the biggest problem—as of July there were nearly double the number of cases in all of 2005.
Wikoff says the virus cycles in prevalence every few years, and he believes New Hampshire is in the rising phase.
After a few years in the cycle, he says, the virus kills enough of the population and cases decline.
While the current strategy of keeping rabies cycling only south of Coos County seems to be working, Dennis Slate at the USDA says he’s looking for ways to eliminate the virus in raccoons altogether.
Slate: Possibly in the long term things like contraception and limited population control—an integration of those techniques offer the greatest chance for eliminating rabies.
In the short term, Slate’s plan is to slowly push the line of the vaccine drops further south.
It just depends on which gets to the raccoons faster—the vaccine bait or the rabies.
SOQ
