Acaricide resistance mechanisms in Rhipicephalus sanguineus
Amanda L. Eiden1, Phillip E. Kaufman1, Faith M. Oi1, Michael J. Dark2,3 and Robert Miller4
1Entomology and Nematology Dept., University of Florida, Gainesville, FL
2College of Veterinary Medicine, University of Florida, Gainesville, FL
3Emerging Pathogens Institute, University of Florida, Gainesville, FL
4USDA, ARS, Cattle Fever Tick Research Laboratory, Edinburg, TX
The brown dog tick, Rhipicephalus sanguineus Latreille, is a common ectoparasite of dogs worldwide. In addition, R. sanguineus is a vector for several Rickettsia, Babesia, and Ehrlichia spp. This three-host tick can complete its entire lifecycle indoors and infest homes. Chemical control methods are heavily relied upon to eliminate household infestations and control ticks on pets. To evaluate acaricide resistance levels and mechanisms ticks were collected from residence and kennel facilities experiencing tick infestations that were difficult to eliminate. Using the larval packet test, we have confirmed resistance to permethrin and fipronil in several Florida R. sanguineus populations. This is the first time acaricide resistance in R. sanguineus has been documented in the United States. In order to accelerate detection and reduce costs for resistance profiling of field-collected ticks, a discriminating dose has been established for a susceptible tick strain. Increased metabolic activity was evaluated with Florida tick populations. Synergist assays and gel electrophoresis have been used to demonstrate an increase in esterase activity, which is known to aid in acaricide detoxification. Knowledge of resistance status and resistance mechanisms is crucial in developing a best management program for this tick and to reduce unnecessary acaricide exposure in the home.
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