Fidelity and foraging at locally infectious zones for anthrax is associated with seasonal greenup patterns in a montane anthrax zone
Topics:
Keywords: anthrax, animal movement, NDVI phenology, site fidelity, disease transmission, GIS, medical geography
Abstract Type: Paper Abstract
Authors:
Jason K Blackburn, Spatial Epidemiology & Ecology Research Lab, University of Florida
Morgan A Walker, Spatial Epidemiology & Ecology Research Lab, University of Florida
Jeremy P. Orange, Spatial Epidemiology & Ecology Research Lab, University of Florida
Samuel A. Canfield, Spatial Epidemiology & Ecology Research Lab, University of Florida
Anni Yang, Department of Geography, University of Oklahoma
Valpa Asher, Turner Enterprises, Inc
Kelly M Proffitt, Montana Fish, Wildlife & Parks
Jose Miguel Ponciano, Department of Biology, University of Florida
Michael H Norris, Spatial Epidemiology & Ecology Research Lab, University of Florida
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Abstract
Anthrax is a globally important zoonosis, affecting wildlife, livestock, and humans. The disease is caused by the spore forming bacterium Bacillus anthracis, which can survive in environmental reservoirs for years. Such reservoirs are created when anthrax-caused animal deaths contaminate the soil and vegetation surrounding the carcass (likely infectious for a ~decade). These locally infectious zones (LIZs) serve as patches for animal visitation and grazing leading to future cases. Bacillus anthacis does not survive equally in all soils, so LIZ persistence can vary. Additionally, for a LIZ from time 0 to be infectious at some future time point, animals much return and use LIZs. We evaluated LIZ visitation by elk using SaTScan-defined space-time foraging patches of GPS collar data and for bison and elk from a long-term camera trap study in Montana, a re-emerging anthrax zone. We previously defined the extent of anthrax risk here using ecological niche models. Here we evaluated landscape-level seasonal phenology. We tested for local clusters of integrated greenup values from MODIS-NDVI using AMOEBA and LISA. Movement data suggested elk return to foraging patches year-after-year within the anthrax risk zone and camera traps confirmed returns to specific LIZs. Bison and elk grazed more at LIZs than control sites and grazing at LIZs was associated with those LIZs in pixels with spatial clusters of drier/browner grass at the start of the greenup season. Together, these data indicate seasonal greenup likely drives anthrax LIZ usage by host species, with LIZs promoting grazing in drier areas, which may spark outbreaks.
Fidelity and foraging at locally infectious zones for anthrax is associated with seasonal greenup patterns in a montane anthrax zone
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Paper Abstract
