PARENT SESSION
Oral Session # 22: Pathogens, Toxins, and Disease I: Modeling ; Mammalian.
Presiding: J Foufopoulos
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Meeting Room 201.
Ecological phylogeography of fox rabies in Ontario.
Real, Leslie*,1, Snaman, Jennifer1, Lambert-Jack, Tracy2, Waller, Lance2, Childs, James3, 1 Department of Biology and the Center for Disease Ecology, Atlanta, GA2 School of Public Health, Atlanta, GA3 Centers for Disease Control and Prevention, Atlanta, GA
ABSTRACT- Often spatial analysis of genetic structure in phylogeographic studies are not coupled to ecological variables and underlying spatial population dynamics. At the same time, epidemic models of disease spread often lack detailed genetic information. Here we present an analysis of the spatial organization of rabies virus genotypes associated with the epidemic expansion of fox rabies from the arctic region into western Ontario. We use the spatial organization of 82 rabies isolates from red fox that have been previously sequenced by S.A. Nadin-Davis (1999) at the N and G genes of this 12 KB single-stranded negative-sense RNA virus. The 82 isolates cluster into 21 distinguishable molecular variants. We applied modern geostatistical methods to determine the spatial location of distinct sequence clusters (by type), the geographic boundaries associated with these clusters arrived at by categorical wombling, and correlations among disease sequence clusters and GIS derived environmental variables (e.g. extent of rivers, human population corridors, vegetation type and cover, and presence or absence of bays and/or lakes). We tested the hypothesis that spatial pattern in sequence variation corresponds to and was generated by the spatial pattern of epidemic expansion of fox rabies in Ontario. Genetic distance and spatial distance are significantly correlated and spatial structure does correspond to underlying ecological variation. The rabies virus appears to genetically differentiate and form distinct spatial paths of expansion where the direction of spread was influenced by the Ottawa River to the north, the Georgian Bay and Lake Huron to the west, and Lake Ontario to the south.
Key words: phylogeography, rabies, spatial disease ecology, epidemics