TURNBULL, CA; DEARING, MD; ST. JEOR, S; Univ. of Utah; Univ. of Utah; Univ. of Nevada, Reno: Effects of species diversity on dynamics of Sin Nombre Hantavirus in deer mice (Peromyscus maniculatus)

Species diversity has been suggested to impact disease prevalence; however, two leading hypotheses predict divergent outcomes. The �Dilution Effect� predicts that higher species diversity reduces disease prevalence by decreasing the effect of the primary disease reservoir. The �Rescue Effect� predicts that higher species diversity increases disease prevalence by increasing alternative disease hosts in the community. We investigated the relationship between species diversity and prevalence of Sin Nombre Hantavirus (SN), a disease hosted primarily by deer mice. In spring and fall 2003, we measured SN prevalence, species diversity and incidences of seroconversion in 14 rodent communities in central Utah using mark-recapture sampling. SN infection in hosts was determined using enzyme-linked immunosorbent assay to detect SN antibodies. Species diversity, as estimated using the Shannon Index, varied from to 0 to 2.4 across sites and species richness varied from 1 to 7. There was a negative relationship between species diversity and deer mouse density, yet changes in diversity were not correlated with SN prevalence. SN prevalence varied across seasons; this result was not due to changes in species diversity, as diversity remained constant across seasons. Incidences of seroconversion were rare (N= 4), however all sites where seroconversions occurred had low species diversity. The site with lowest diversity had the highest incidence of seroconversion. Our data suggest species diversity does not significantly influence the prevalence of SN in deer mice. However, overall population densities and SN prevalence were significantly lower across our study sites than in earlier studies, likely due to prolonged drought. Thus, it is possible that species diversity may have an impact on disease prevalence at higher population densities.