Can Vaccines Replace the Hunt?
Two brucellosis vaccines have been developed for cattle, and one is being tested for use in bison. But the results to date have not been promising, according to Tom Roffe, chief of wildlife health for the U.S. Fish and Wildlife Service. “[The vaccine] confers some immunity in cattle, but it is not great,” he said, noting that cattle in Wyoming that had been vaccinated still contracted brucellosis in 2003. “We know [the vaccine]’s not highly effective in bison.” Furthermore, Roffe said, tracking and vaccinating 4,900 wild bison is not like giving shots to animals in pens. Given the low level of protection the vaccination affords, he said, it is not worth the expense to vaccinate the park’s herds until a better vaccine is available. Steven Olsen, a researcher at the USDA’s Animal Research Service, said promising work is underway. “There are new vaccine strains, and new technologies have been developed to make more strains,” Olsen said. “Completing the research is not simple. It is going
