ECOLOGY AND DEMOGRAPHICS OF HANTAVIRUS INFECTIONS IN RODENT POPULATIONS IN THE WALKER RIVER BASIN OF NEVADA AND CALIFORNIA

To study the ecologic correlates of hantavirus in deer mice (Peromyscu s maniculatus), we sampled 114 sites in the Walker River Basin of Neva da and California in 1995-1996. Blood samples were tested for antibody to hantavirus, and a subset of samples was also tested for virus RNA by reverse transcription-polymerase chain reaction. Average prevalence of antibody-positive mice was 17%, with heavier males the most Likely to be infected. Antibody prevalence varied within repeatedly sampled sites from 0% to 50% over the course of several months, suggesting pos sible infection cycles. Although there was no linear correlation betwe en deer mouse density and antibody prevalence on sample sites, more co mplex relationships between density and prevalence appeared likely. Sp ecifically, infections were less likely where rodent densities were lo wer than a critical threshold value. However, above this value, densit y had no effect on prevalence.