OOS 55-5 - Introduced ungulate intensifies cattle fever tick exposure risk for cattle in the southeast United States

Cattle fever ticks are the most economically important pests of cattle in the world, and the recent increase of tick incursions in Texas challenges the Cattle Fever Tick Eradication Program (CFTEP). Heightened pressure from growing wildlife host populations along the US-Mexico border is a pressing complication for CFT control initiatives. Spatially explicit prediction of wildlife host distribution may provide information essential for allocation of resources by the CFTEP. In this study, we use species distribution models to project the distribution of white-tailed deer and nilgai in the southeastern USA to improve our understanding of cattle exposure to native and introduced wildlife hosts of cattle fever ticks. Our results reveal that ubiquitous white-tailed deer presence in the southeastern USA tapers off in the arid west, limiting exposure of US cattle to historic cattle fever tick wildlife hosts along the US-Mexico border. Additionally, the nilgai distribution model fit in the species' native range indicates a moderate probability of habitat suitability throughout the southeastern USA, and a high probability of habitat suitability in southern and eastern Texas. The expansion of nilgai across their projected suitable habitat increases cattle exposure to cattle fever tick wildlife hosts, especially in sensitive, transitional areas along the US-Mexico border. We posit that modeling existing wildlife hosts and the potential range expansion of introduced wildlife hosts, and overlaying these models with cattle inventory will ultimately help direct efforts to monitor ticks, prevent incursions, and initiative early interventions.