Considerations for improved recommendations for the Cattle Fever Tick Control Program

The southern cattle tick, Rhipicephalus (Boophilus) microplus, is a cosmopolitan cattle pest in tropical and semi-tropical parts of the world. These ticks complete their life cycle on a single host and can transmit the causative agent of Bovine Babesiosis, which results in high morbidity and mortality. A concerted effort between federal and state governments successfully eradicated the tick throughout most of the United States by the 1940’s, but a permanent quarantine zone near the US-Mexico border remains. This permanent quarantine zone prevents reestablishment of the tick to the broader U.S., which is under threat by importation of cattle from Mexico (~1M annually), and free ranging white-tailed deer, and Nilgai movement across the Rio Grande River. Animals legally imported undergo a “scratch inspection” by trained inspectors to palpate the skin for adult ticks; however, the other life stages also on the same animals are largely missed due to the small size ( < 1 mm) of the larvae and moderately larger nymphs. Research conducted in conjunction with the Cattle Fever Tick Research Lab has found that a trained inspector could find no larvae and < 2.5% of nymphs. This research has revealed differences in predilection sites of larval and nymphal R. microplus that may help develop a targeted search protocol for tick scratchers at livestock inspection stations along the US-Mexico border. Other program recommendations will also be presented.