Ecological Systems Laboratory, Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, 77843, USA.
Department of Entomology, Texas A&M AgriLife Research, College Station, TX, 77843, USA.
Parasit Vectors. 2021 May 1;14(1):231. doi: 10.1186/s13071-021-04724-3.
Cattle fever ticks (CFT), Rhipicephalus (Boophilus) annulatus and R. (B.) microplus, are vectors of microbes causing bovine babesiosis and pose a threat to the economic viability of the US livestock industry. Efforts by the Cattle Fever Tick Eradication Program (CFTEP) along the US-Mexico border in south Texas are complicated by the involvement of alternate hosts, including white-tailed deer (Odocoileus virginianus) and nilgai (Boselaphus tragocamelus).
In the present study, we use a spatially explicit, individual-based model to explore the potential effects of host species composition and host habitat use patterns on southern cattle fever ticks (SCFT, R. (B.) microplus) infestation dynamics and efficacy of eradication schemes.
In simulations without eradication efforts, mean off-host larval densities were much higher when cattle were present than when only white-tailed deer and nilgai were present. Densities in mesquite and meadows were slightly higher, and densities in mixed brush were much lower, than landscape-level densities in each of these scenarios. In eradication simulations, reductions in mean off-host larval densities at the landscape level were much smaller when acaricide was applied to cattle only, or to cattle and white-tailed deer, than when applied to cattle and nilgai. Relative density reductions in mesquite, mixed brush, and meadows depended on host habitat use preferences. Shifting nilgai habitat use preferences increasingly toward mixed brush and away from mesquite did not change mean off-host larval tick densities noticeably at the landscape level. However, mean densities were increased markedly in mesquite and decreased markedly in mixed brush, while no noticeable change in density was observed in meadows.
Our results suggest that continued integration of field data into spatially explicit, individual-based models will facilitate the development of novel eradication strategies and will allow near-real-time infestation forecasts as an aid in anticipating and preventing wildlife-mediated impacts on SCFT eradication efforts.
牛热蜱（CFT），即环形泰勒焦虫（Rhipicephalus）（Boophilus）annulatus 和 R.（B.）microplus，是引起牛巴贝斯虫病的微生物的载体，对美国牲畜业的经济生存能力构成威胁。美国德克萨斯州南部美墨边境的牛热蜱根除计划（CFTEP）努力受到替代宿主的参与的影响，包括白尾鹿（Odocoileus virginianus）和印度野牛（Boselaphus tragocamelus）。
在本研究中，我们使用空间明确的个体基础模型来探索宿主物种组成和宿主栖息地利用模式对南方牛热蜱（SCFT，R.（B.）microplus）侵染动态和根除方案效果的潜在影响。
在没有根除努力的模拟中，当有牛存在时，离宿主幼虫的平均密度比只有白尾鹿和印度野牛存在时高得多。在牧豆树和草地中的密度略高，而在混合灌木丛中的密度比这些情况下的景观水平密度低得多。在根除模拟中，当仅在牛上或在牛和白尾鹿上使用杀螨剂时，景观水平上离宿主幼虫的平均密度减少要比在牛和印度野牛上使用杀螨剂时小得多。牧豆树、混合灌木丛和草地的相对密度减少取决于宿主的栖息地利用偏好。将印度野牛的栖息地利用偏好越来越多地从牧豆树转移到混合灌木丛，而不在景观水平上明显改变离宿主幼虫的平均密度。然而，在牧豆树中密度显著增加，在混合灌木丛中密度显著降低，而在草地中密度没有明显变化。
我们的结果表明，将实地数据持续纳入空间明确的个体基础模型将有助于制定新的根除策略，并允许进行近乎实时的侵染预测，以帮助预测和防止野生动物对 SCFT 根除工作的影响。
