Antibody to sin nombre virus in rodents associated with peridomestic habitats in west central Montana.

Abstract

Abstract. Most human cases of hantavirus pulmonary syndrome are acquired in the peridomestic environment, yet studies of the ecology and infection dynamics in the reservoir host, the deer mouse (Peromyscus maniculatus), have focused on sylvan populations. We describe a 2.5-year study of hantavirus infection in rodents associated with peridomestic habitats in west central Montana. Antibodies reactive with Sin Nombre virus (SNV) were found in five species. Overall SNV antibody prevalence was highest among deer mice (25% of individuals tested). As has been demonstrated for sylvan populations, the antibody-positive component of the deer mouse population consisted of a higher proportion of adults and males. However, the prevalence of antibodies to SNV was higher in this study than has been reported in most sylvan studies. The average monthly proportion of deer mouse blood samples with antibodies to SNV ranged from approximately 20% to 25% and was highest in the late spring/early summer. The higher SNV antibody prevalence in peridomestic compared with sylvan settings may be related to behavioral differences and/or potentially longer survival of the virus deposited inside buildings. Peridomestic settings presented higher concentrations of virus and may present a higher risk of human infection than do sylvan settings.

Long-Term Dynamics of Sin Nombre Viral Rna and Antibody in Deer Mice in Montana

“…In Montana, where an average of 13% of sylvan deer mice had antibody to SNV (1994-98) , one could expect about 3% (0.22 ϫ 13%) of individuals in the population to have SNV RNA in their blood at any particular time. In peridomestic populations in Montana, in which an average antibody prevalence of 25% has been observed (Kuenzi et al, 2001), one might expect about 7% (0.28 ϫ 25%) of individuals in the population to have SNV RNA in their blood at any particular time.…”

“…In Montana, breeding in deer mice, as indicated by an increase in the proportion of males with testes in the scrotal position, begins during the apparently most physiologically stressful time of year, January and February, in both sylvan and peridomestic settings (Kuenzi et al, 2001). Weather conditions during these months are characterized by cold temperatures (as low as Ϫ38 C) and persistent snow cover.…”

“…Of 2,185 individuals captured in peridomestic settings (Kuenzi et al, 2001), we documented 131 that serocoverted. Most of these (88/ 131, 67%) were males in a population comprising essentially 50% males.…”

“…Detailed descriptions of the peridomestic sites and populations can be found in Kuenzi et al (2001), while details of the sylvan sites and populations are published in Douglass et al (2001).…”

“…The sixth sylvan site was trapped monthly from January 1996 through December 1997. All live trapping was conducted according to standardized protocols Kuenzi et al, 2001). Briefly, captured deer mice in both peridomestic and sylvan habitats were transported to a central site for processing, where pertinent data (species, gender, mass, age, and reproductive condition) were recorded and blood samples were collected.…”