title: Comparison of in vitro and in vivo ectoparasiticide activity of experimental benzimidazole-carbamate with permethrin and amitraz.
abstract: A series of in vitro and in vivo bioassays were conducted to assess the ectoparasiticide activity of isopropyl-4-nitro-2,6-bis(trifluoromethyl)-1-benzimidazole-carbamate, an experimental benzimidazole-carbamate class compound. This compound was less potent than permethrin against ectoparasiticide-susceptible larvae of the lone star tick, Amblyomma americanum (L.) (Acari: Ixodidae); larvae of the southern cattle tick, Boophilus microplus (Canestrini); and adult stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae) in vitro, but it was significantly more potent than permethrin against the Santa Luiza strain of B. microplus known to possess high-level resistance to amitraz and pyrethroids. In contrast, the benzimidazole-carbamate was substantially more efficacious than permethrin when applied topically onto rats that were infested with A. americanum nymphs. These results suggest that this experimental compound may be a viable candidate ectoparasiticide that retains significant activity against resistant B. microplus and also suggests that the benzimidazole-carbamate chemistry may be useful for addressing the growing problem of resistance in ectoparasites.
authors.affiliation: Elanco Animal Health Research and Development, A Division of Eli Lilly & Company, 2001 W. Main Street, Greenfield, IN 46140, USA.
authors.forename: W Hunter
authors.initials: WH
authors.lastname: White
authors.forename: Steven M
authors.initials: SM
authors.lastname: Bauer
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Zhao
authors.forename: Jesus A
authors.initials: JA
authors.lastname: Gutierrez
authors.forename: Charles K
authors.initials: CK
authors.lastname: Smith
mesh_terms: D000818:Animals; D000977:Antiparasitic Agents / Q000008:administration & dosage; D001562:Benzimidazoles / Q000008:administration & dosage; D002219:Carbamates; D004305:Dose-Response Relationship, Drug; D026863:Ixodidae; D007814:Larva; D026023:Permethrin; D051381:Rats; D014052:Toluidines
chemical_list: D000977:Antiparasitic Agents; D001562:Benzimidazoles; D002219:Carbamates; D014052:Toluidines; C014983:amitraz; D026023:Permethrin