Genetic relatedness of deer mice (Peromyscus maniculatus) infected with Sin Nombre virus.

The deer mouse (Peromyscus maniculatus) is the primary rodent host of Sin Nombre virus (SNV), the principal etiologic agent of hantavirus pulmonary syndrome in the United States. Many characteristics of SNV infections of deer mice are unknown. To better understand the transmission mechanisms of SNV in deer mice, we conducted mark-recapture sampling and genetic analyses to study deer mouse population density and genetic relatedness from 2001 to 2002. We genotyped each deer mouse at 10 microsatellite loci to estimate relatedness among SNV-infected and SNV-uninfected groups, demographic categories, and individuals. Estimates of average overall population densities ranged from 1.15 to 14.95 deer mice/ha. Estimates of average population densities of SNV-infected deer mice ranged from 0 to 1.55 deer mice/ha. When evaluated as groups at one of two study sites, SNV-infected deer mice were more related to one another, on average, than they were to their uninfected cohorts. Pairwise coefficients of relatedness among individuals indicated that several deer mice infected with SNV were closely related. Most infected mice were males. These results are consistent with the hypothesis that transmission of SNV often is associated with breeding activities and aggression among males during the breeding season and suggest that post-birth behavioral associations among adults and juveniles may be a factor in the transmission of SNV.