Jason K. Blackburn, PhD
Department of Geography
California State University, Fullerton
Field validation of fundamental niche predictions of Bacillus anthracis in the U.S. and potential changes in the geographic distribution of B. anthracis in the U.S. in 2050
Wednesday, March 18th, 2009
4-5pm, Room G-112 HPNP Building
Field validation of fundamental niche predictions of Bacillus anthracis for the U.S. and potential changes in the geographic distribution of B. anthracis in the U.S. in 2050
Jason K. Blackburn, Ph.D.
Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, California State University, Fullerton, California, USA
Despite various control efforts, anthrax remains a disease of concern for wildlife manager and livestock ranchers throughout Texas, the Dakotas, Minnesota, Montana, California, and Nevada. Given that most species affected are free roaming wildlife, vaccination efforts remain untenable and proactive surveillance and carcass disposal during outbreaks are key to proper control and management. This is coupled with fact that Bacillus anthracis, the causative agent, is a soil-borne organism that, under the right conditions, can survive for prolonged periods of time and lead to future outbreaks. Because of this, it is important to understand the potential geographic distribution of the disease agent and identify those areas that should require surveillance and preemptive vaccination in livestock. Ecological niche modeling provides a predictive approach to estimating the geographic potential for B. anthracis and organizing surveillance priorities. While many niche modeling approaches are criticized for over predicting disease distributions, this study will illustrate the usefulness of these approaches in the context of the classical literature on fundamental and realized niches and validate the fundamental niche approach with field data from recent outbreaks in western Montana. At the same time, several studies have confirmed that global increases in green house gases and temperature may have drastic changes to the environment in the future. This may change the geographic distribution of B. anthracis and the potential for anthrax outbreaks across the organism’s range. To investigate this in the US, we employed ecological niche modeling and present and future climate scenarios from the Inter-Governmental Panel on Climate Change. Results suggest that the current day distribution in the northern states may see limited geographic change while earlier green up periods and prolonged summer temperatures may increase the outbreak season. In contrast, south and west Texas, an area heavily impacted today by the disease, may be too warm and dry for the organism to survive. In these southern areas we speculate a contraction of the organism’s distribution northward with minimal change in the outbreak season in areas of Texas that remain in the predicted enzootic range of B. anthracis. Results from multiple future scenarios are compared to evaluate inter-model variability.