Do Unusual Site-Specific Population Dynamics of Rodent Reservoirs Provide Clues to the Natural History of Hantaviruses?

Abstract

Between January 1995 and November 1997, longitudinal mark-recapture studies of rodent hosts of hantaviruses in a disturbed microhabitat within a shortgrass prairie ecosystem in southeastern Colorado (USA) were conducted. The site was distinguished by edaphic and floristic characteristics unique to this area and associated with historical land use 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 maniculatus and Reithrodontomys megalotis, had unusually rapid turnover, a younger age structure, and a much lower prevalence of antibody to Sin Nombre virus than did populations at nearby sites in more typical shortgrass prairie and canyon habitats. Based on these findings, we suggest that a stable resident population of the reservoir is critical to the maintenance of hantaviruses at a given site, and we hypothesize that long-lived, persistently infected rodents are the principal transseasonal reservoir of hantaviruses.

Sin Nombre Virus Infection of Deer Mice in Montana: Characteristics of Newly Infected Mice, Incidence, and Temporal Pattern of Infection

“…Alternatively, the finding that initially antibody-negative deer mice were not trapped for long periods of time and then were captured as antibody-positive may suggest that deer mice may move long distances or have enlarged winter home ranges. Such movement may be important in reintroducing and maintaining viral infections in local populations, if they are wide-ranging and shedding SNV, as has been suggested (Root et al, 1999;Calisher et al, 2001).…”

“…The apparent decline in breeding is related to dilution of the population by young of the year, which may not reach maturity during that year. However, there may be a sufficient number of older, SNV-infected deer mice in the population to sustain transmission and, therefore, to sustain the rate of antibody acquisition (Calisher et al, 2001).…”

“…Considerable information regarding the ecology of the principal rodent host of SNV, the deer mouse (Peromyscus maniculatus), and the prevalence of antibodies against SNV has been accumulated and reported from these studies (Douglass et al, 1996(Douglass et al, , 2001Mills et al, 1997Mills et al, , 1998Abbott et al, 1999;Calisher et al, 1999Calisher et al, , 2001. Specifically, population sizes of rodent hosts of SNV are spatially and temporally variable, as is the prevalence of antibody to SNV.…”

Deer Mouse Movements in Peridomestic and Sylvan Settings in Relation to Sin Nombre Virus Antibody Prevalence

“…There is strong evidence that deer mice horizontally infect one another with SNV through biting during intraspecific aggressive encounters (Calisher et al, 2001;Douglass et al, 2001). Peridomestic settings may support higher densities of deer mice than do sylvan settings, and higher densities may lead to more frequent aggressive interactions.…”

“…In addition to being bitten, deer mice can be exposed to SNV by inhaling aerosolized virus (Calisher et al, 2001). Thus, buildings may present a similar milieu of risk of exposure to SNV for deer mice as they do for humans.…”