Determination of metabolic resistance mechanisms in pyrethroid‐resistant and fipronil‐tolerant brown dog ticks

Abstract

Rhipicephalus sanguineus (Latreille) (Ixodida: Ixodidae) is a three-host dog tick found worldwide that is able to complete its' entire lifecycle indoors. Options for the management of R. sanguineus are limited and its' control relies largely on only a few acaricidal active ingredients. Previous studies have confirmed permethrin resistance and fipronil tolerance in R. sanguineus populations, commonly conferred by metabolic detoxification or target site mutations. Herein, five strains of permethrin-resistant and three strains of fipronil-tolerant ticks were evaluated for metabolic resistance using synergists to block metabolic enzymes. Synergist studies were completed with triphenyl phosphate (TPP) for esterase inhibition, piperonyl butoxide (PBO) for cytochrome P450 inhibition, and diethyl maleate (DEM) for glutathione-S-transferase inhibition. Additionally, increased esterase activity was confirmed using gel electrophoresis. The most important metabolic detoxification mechanism in permethrin-resistant ticks was increased esterase activity, followed by increased cytochrome P450 activity. The inhibition of metabolic enzymes did not have a marked impact on fipronil-tolerant tick strains.

Identification of permethrin and etofenprox cross‐tolerance in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae)

“…Through the use of synergist assays, esterase and cytochrome P450 activities were shown to be the most important resistance mechanisms among permethrin‐resistant Florida and Texas R. sanguineus (s.l.) populations . These findings suggest that multi‐acaricide cross‐resistance caused by metabolic detoxification may be present in the Grenada, Mexico‐Merida, and Mexico‐Nayarit populations.…”

“…populations. 30 These findings suggest that multi-acaricide cross-resistance caused by metabolic detoxification may be present in the Grenada, Mexico-Merida, and Mexico-Nayarit populations. Additional studies are needed to evaluate the selection pressure exerted by non-SP acaricides on brown dog tick population resistance mechanisms.…”

“…The mutation was present in the Mexico‐Merida and Mexico‐Nayarit surviving larvae, but homozygous SNP levels were low indicating some other resistance mechanism is acting to provide resistance to the applied acaricides. Although increased esterase activity confers permethrin resistance in R. sanguineus , it is not a likely candidate to explain etofenprox tolerance as etofenprox is a non‐ester pesticide . However, cytochrome P450's, such as CYP6P4 , do detoxify permethrin and etofenprox in the malaria vector, Anopheles arabiensis (Patton; Diptera: Culicidae) , and warrant further investigation in R. sanguineus .…”

Towards a Sustainable One Health Approach to Crimean–Congo Hemorrhagic Fever Prevention: Focus Areas and Gaps in Knowledge

“…The use of synthetic acaricides on livestock animals has long been a favored methodology for ectoparasite and tick control throughout the world [ 122 ]. Organophosphates are the major chemical acaricides used for ectoparasite control and include compounds, such as pyrethroids, macrocyclic lactones, and amidines, among others [ 123 ]. Acaricides are a comparatively inexpensive method for tick control and can be easily administered in multiple ways [ 124 ], including dipping, footbaths, or manual sprayers.…”

Novel and Selective Rhipicephalus microplus Triosephosphate Isomerase Inhibitors with Acaricidal Activity

“…Nowadays, organophosphates are the major chemical acaricides in use (with high environmental impact), which includes pyrethroids, macrocyclic lactones, amidines (like amitraz), fipronil, and fluazuron [ 19 , 20 ]. These can be administered in different forms, such as dip concentrates, spraying, injection, or pour-on treatments [ 4 , 21 ].…”