In 2001, the USDA's Wildlife Services division began dropping edible bait blocks filled with vaccine along a roughly north-south line across east-central West Virginia. The idea was to prevent raccoon rabies from spreading westward from the mountains, where it had become established, to the state's western lowlands.
The vaccine had the desired effect. The line hasn't moved much since. And now, with the new vaccine, Chipman and other USDA officials believe it might be possible to eradicate the disease.
He based his optimism on last summer's test of the ONRAB vaccine in Monroe County.
"We chose Southern West Virginia for the test because it's in the center of our Oral Rabies Vaccine line," he said.
Researchers dropped 77,000 ONRAB-laced baits from aircraft, and set out an additional 1,500 ground baits. Chipman said "a good percentage" of raccoons captured afterwards had rabies antibodies in their system.
"We're really excited about that," he said.
As to the future, Chipman said the West Virginia ONRAB trial will likely be replicated, and that raccoon populations in areas that get the V-RG vaccine would be tested for rabies antibodies.
Since the USDA began experimenting with oral raccoon rabies vaccines in the mid-1980s, more than 8 million vaccine blocks have been dropped in 18 states. More than 42,000 raccoons have been sampled for rabies and its antibodies, and 161 raccoon population-density studies have been conducted.
According to the U.S. Centers for Disease Control and Prevention, approximately 6,000 cases of rabies were reported for 2010 within the U.S. and Puerto Rico. Two humans died.
"The reason we want to eliminate raccoon rabies is to help ensure the public's health," Chipman said. "The U.S. has been free of canine rabies since 2007. Now we want to eliminate raccoon- and other wildlife-borne strains of the disease."