Prevalence and geographic genetic variation of hantaviruses of New World harvest mice (Reithrodontomys): identification of a divergent genotype from a Costa Rican Reithrodontomys mexicanus.

We recently described a novel hantavirus (HMV-1) of the western harvest mouse Reithrodontomys megalotis. Screening of 181 additional specimens of Reithrodontomys from the United States and Mexico, including samples of R. mexicanus, R. sumichrasti, and R. gracilis of Costa Rica, for antibodies to hantavirus nucleocapsid protein revealed a widespread enzootic of hantavirus infection. Genetic analyses of 7 S genomes of Reithrodontomys-associated hantaviruses demonstrated that the enzootic of HMV-1 extends from central Mexico into the southwestern United States. A presumed deer mouse hantavirus was found in an R. megalotis animal in Mexico. A highly divergent HMV-1-like virus, tentatively called HMV-2, was identified in a Costa Rican R. mexicanus. These data suggest a longstanding radiation of hantaviruses among New World harvest mice. We identify possible opportunities for genetic exchange among hantaviruses of related rodent hosts.