Spread of brucellosis blamed on elk, not bison or feed grounds

Efforts to control brucellosis in cattle around Yellowstone National Park may be focusing on the wrong wildlife suspects, according to new DNA research on the disease. The study suggests elk are the most likely source of brucellosis outbreaks in domestic cattle. That complicates the work of officials around Yellowstone charged with controlling the spread of brucellosis. Suspicion that bison were the main spreaders of the disease to cattle prompted extensive restrictions on bison trying to migrate out of the park into grazing lands of Montana, Idaho and Wyoming. Those restrictions have included hazing the herds back into the park, and hunting, butchering or quarantining thousands of bison that could not be driven back into Yellowstone.“Of all the cases we had, we found no direct links from bison to livestock,” said Pauline Kamath, U.S. Geological Survey ecologist and lead author of the study. “That’s suggesting there’s little transmission from bison to animals in other areas in the Greater Yellowstone.” Brucellosis causes infected females to abort their calves. Its presence in an area may require ranchers to quarantine their herds and incur expensive testing and vaccinations before the animals can be sold or moved. The Greater Yellowstone area is the last reservoir of the disease in North America, and about 20 private herds of cattle or bison have reported infections in Montana, Idaho and Wyoming since 2002...more