Simulated dynamics of southern cattle fever ticks (Rhipicephalus (Boophilus) microplus) in South Texas, USA: investigating potential wildlife impacts on cattle eradication

Authors: WANG, HSIAO-HSUAN - Texas A&M University; GRANT, WILLIAM - Texas A&M University; TEEL, PETE - Texas A&M University; Lohmeyer, Kimberly - Kim; Perez De Leon, Adalberto - Beto

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2021
Publication Date: 5/2/2021
Citation: Wang, H., Grant, W.E., Teel, P.D., Lohmeyer, K.H., Perez De Leon, A.A. 2021. Simulated dynamics of southern cattle fever ticks (Rhipicephalus (Boophilus) microplus) in South Texas, USA: investigating potential wildlife impacts on cattle eradication. Parasites & Vectors. 14:231. https://doi.org/10.1186/s13071-021-04724-3.
DOI: https://doi.org/10.1186/s13071-021-04724-3

Interpretive Summary: Cattle fever ticks (CFT) are vectors of babesiosis in cattle and remain a threat to the livestock industry in the U.S. Efforts by the Cattle Fever Tick Eradication Program along the U.S.-Mexico border in south Texas are complicated by the involvement of non-cattle tick including white-tailed deer and nilgai antelope. Here, we interrogated potential impacts on CFT eradication efforts by expanding a spatially-explicit and individual-based model originally developed to simulate cattle-deer interactions. More specifically, nilgai was included in the simulations to determine how the involvement of multiple wildlife host species affect off-host larval tick distribution and abundance during treatments to eradicate CFT. This approach found the creation of tick larvae hotspots enabled by wildlife host habitat preferences. Our results support field observations on CFT refugia across the landscape during eradication efforts involving the use of acaricides to treat infested hosts. Our simulations indicated that host-seeking larval distribution patterns may be impacted by wildlife host habitat preferences in a manner that creates larval “hotspots,” which may become larval refugia during acaricide-based eradication efforts. The contribution of this research to the development of novel strategies for sustainable CFT eradication is discussed. Continued integration of field data into CFT population models will allow near-real-time infestation forecasts as an aid in anticipating and preventing wildlife host impacts on CFT eradication efforts.

Technical Abstract: Cattle fever ticks (CFT), Rhipicephalus (Boophilus) annulatus and R. (B.) microplus, are vectors of the microbes causing bovine babesiosis and remain a threat to the economic viability of the livestock industry in the U.S. after they were eradicated in 1943. Efforts by the Cattle Fever Tick Eradication Program along the U.S.-Mexico border in south Texas are complicated by the involvement of alternate hosts including white-tailed deer (Odocoileus virginianus) and nilgai (Boselaphus tragocamelus). Here, we interrogated potential impacts on CFT eradication efforts by expanding a spatially-explicit and individual-based model originally developed to simulate cattle-deer interactions. More specifically, nilgai was included in the simulations to investigate how the involvement of multiple wildlife host species affect off-host larval distribution and abundance during treatments to eradicate CFT. This approach revealed the creation of tick larvae hotspots enabled by wildlife host habitat preferences. Our results support field observations on CFT refugia across the landscape during eradication efforts involving the use of acaricides to treat infested hosts. Our simulations indicated that host-seeking larval distribution patterns may be affected by wildlife host habitat preferences in a manner that creates larval “hotspots,” which may become larval refugia during acaricide-based eradication efforts. The contribution of this research to the development of novel strategies for sustainable CFT eradication is discussed. Continued integration of field data into spatially-explicit, individual-based models will allow near-real-time infestation forecasts as an aid in anticipating and preventing wildlife-mediated impacts on CFT eradication efforts.