Meeting Abstract
15.5 Jan. 4 Ecology of Rabies and Immunity in Brazilian Free-tailed Bats (Tadarida brasiliensis). TURMELLE, Amy/S*; ALLEN, Louise/C; JACKSON, Felix/R; MENDONCA, Mary/T; KUNZ, Thomas/H; RUPPRECHT, Charles/E; MCCRACKEN, Gary/F; Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN.; Rabies and Poxvirus Section, Centers for Disease Control and Prevention, Atlanta, GA.; Center for Ecology and Conservation Biology, Boston University, Boston, MA.; Rabies and Poxvirus Section, Centers for Disease Control and Prevention, Atlanta, GA.; Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN.; Department of Biological Sciences, Auburn University, Auburn, AL.; Center for Ecology and Conservation Biology, Boston University, Boston, MA.; Rabies and Poxvirus Section, Centers for Disease Control and Prevention, Atlanta, GA.; Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN. aturmell@utk.edu
Brazilian free-tailed bats (Tadarida brasiliensis) have extreme variation in their behavioral and roosting ecology, often forming especially large roosting aggregations in Texas. Among bats, they are one of the most frequently submitted species for rabies testing, suggestive of frequent contact with humans, particularly in Texas. The objective of this study was to investigate the role of ecological variation in predicting the prevalence of rabies in Brazilian free-tailed bats. We sampled wild-caught bats (N=709) at 6 sites in south-central Texas from May-October, 2005. Rabies antibody titers of blood plasma were determined using the MRFFIT, and the presence of viral RNA in the saliva was tested with RT-PCR. Viral isolations were attempted, for RT-PCR positives, to investigate the infective nature of the viral RNA present in the saliva. Of 534 bats, 40.3% tested seropositive. Mean seroprevalence was not significantly different at 5 of 6 sites (range 43.2%-53.8%), but one cave had exceptionally low mean seroprevalence (17.9%, &alpha=0.05). Seasonally, 3 of 6 sites showed significant variation in seroprevalence (p<0.005) at 2 caves and 1 bridge site. The saliva of 1.19% (2 of 168) bats tested positive for rabies viral RNA. These positives occurred at two sites, one cave and one bridge, in May. Bats at the bridge site seemed to exhibit a peak in seroprevalence in response to this event (p=0.049), whereas the response of bats at the cave site was not significant. The data indicate that free-tailed bats in caves and bridges are regularly exposed to rabies virus, and often survive these events. Analyses of mean seroprevalence by roost type indicate that bats roosting in bridges have significantly higher seroprevalence than bats roosting in caves (p=0.013), and potentially greater exposure to rabies virus. Variation in disease exposure will be discussed in the context of previously reported immune competence of bats at 4 of the 6 sites.
