Do unusual site-specific population dynamics of rodent reservoirs provide clues to the natural history of hantaviruses?

Between January 1995 and November 1997, longitudinal mark-recapture studies of rodent hosts of hantaviruses in a disturbed microhabitat within a short grass prairie ecosystem in southeastern Colorado (USA) were conducted. The site was distinguished by edaphic and floristic characteristics unique to t his area and associated with historical land rise patterns, as well as the year-around availability of water from a functioning windmill. Populations of two common rodent species that are hosts for hantaviruses, Peromyscus ma niculatus and Reithrodontomys megalotis, had unusually rapid turnover, a yo unger age structure, and a much lower prevalence of antibody to Sin Nombre virus than did populations at nearby sites in more typical shortgrass prair ie and canyon habitats. Based on these findings, we suggest that a stable r esident population of the reservoir is critical to the maintenance of hanta viruses at a given site, and we hypothesize that long-lived, persistently i nfected rodents are the principal transseasonal reservoir of hantaviruses.