Chronic wasting disease (CWD) is a fatal neurologic infection of deer and elk that is caused by prions. Unlike mad cow disease,CWDis easily transmitted among its cervid hosts, and epidemics are occurring in the United States and Canada. Dennis Heisey of the U.S. Geological Survey's National Wildlife Center in Madison, Wis., et al. show that four species of common North American rodents are easily infected by intracerebral injection. "This is concerning because rodents frequently scavenge tissue from dead animals such as deer," says Heisey. They, in turn, "are often consumed by other animals, particularly natural predators, but also cattle and humans, when rodents accidentally get trapped in grain or hay. Thus, they may serve as a bridge species." Another finding could change scientific understanding of CWD pathogenesis. "It has been postulated that a species' susceptibility or resistance to CWD is due to the amino acid sequence of its prion protein," says Heisey. "We were surprised to find that the highly CWD-susceptible red-backed voles carried the allegedly CWD-resistance-conferring amino acid sequence."

(D. M. Heisey, N. A. Mickelsen, J. R. Schneider, C. J. Johnson, C. J. Johnson, J. A. Langenberg, P. N. Bochsler, D. P. Keane, and D. J. Barr. 2010. Chronic wasting disease (CWD) susceptibility of several North American rodents that are sympatric with cervid CWD epidemics. J. Virol. 84:210-215.)