Leveraging location intelligence and individual-based modeling to simulate Rhipicephalus microplus infestation and eradication dynamics at the cattle-wildlife interface

Cattle fever ticks (CFT), <i>Rhipicephalus</i> (<i>Boophilus</i>) <i>annulatus</i> and <i>R</i>. (<i>B</i>.) <i>microplus</i>, threaten the economic security of the USA cattle industry as vectors of <i>Babesia bigemina</i> and <i>B. bovis</i>. Of the two CFT, <i>R</i>. <i>microplus</i> has a more invasive biology and thrives in tropical and subtropical ecosystems. The U.S. Cattle Fever Tick Eradication Program successfully eliminated CFT from the southern USA and has since prevented CFT re-establishment by operating surveillance and quarantine in South Texas, including the permanent quarantine zone along the Texas-Mexico border. However, introductions and successful establishment of alternate CFT hosts, including white-tailed deer (<i>Odocoileus virginianus</i>) and nilgai (<i>Boselaphus tragocamelus</i>) in the Tamaulipan biome, have complicated eradication efforts. We used location intelligence and a spatially explicit, individual-based model to simulate potential impacts of wildlife hosts on <i>R</i>. <i>microplus</i> infestation/eradication dynamics in the Laguna Atascosa National Wildlife Refuge that encompasses a brushland ecosystem with diverse coastal habitats, including parts of a lagoon in South Texas. Results of our hypothetical eradication scenarios suggest that even sparse populations of wildlife hosts can maintain <i>R</i>. <i>microplus</i> populations in habitat-specific refugia during eradication efforts. The present model version is the first to have incorporated a georeferenced representation of a real landscape and to have integrated site-specific field data on climatic conditions and cattle movement patterns. Model forecasts of spatially explicit chronologies of changes in <i>R</i>. <i>microplus</i> densities can aid in <i>a priori</i> evaluation of field sampling strategies and treatment applications in specific landscapes under specific environmental conditions.