Transmission of an arenavirus in white-throated woodrats (Neotoma albigula), southeastern Colorado, 1995-1999

From 1995 to 1999, we conducted longitudinal studies of white-throated wood rats (Neotoma albigula) in southeastern Colorado. Forty-five (42.9%) of 105 female and 15 (26.8%) of 56 male N. albigula had antibodies against Whitew ater Arroyo virus (WWAV). Sixteen female and three male N. albigula serocon verted during the study period, most of them during July-November. when pop ulation densities are highest. Analyses of longevity data, minimum numbers alive and infected, movements, and weight data suggest that the dominant mo de of WWAV transmission among white-throated woodrats in Colorado is direct contact. WWAV was recently reported to cause fatal infection in humans. Ou r findings will lead to better assessment of the public health threat posed by infected woodrats and may be useful in predicting periods of increased risk for human infection.