title: The extent of acaricide resistance in 1-, 2- and 3-host ticks on communally grazed cattle in the eastern region of the Eastern Cape Province, South Africa.
abstract: In order to determine the extent of acaricide resistance in the eastern region of the Eastern Cape Province 1-, 2- and 3-host ticks were collected from cattle at 59 dip-tanks over a period of 2 years. These ticks were tested for resistance against 3 compounds, namely amitraz, cypermethrin and chlorfenvinphos. The Shaw Larval Immersion Test detected emerging resistance to amitraz in Rhipicephalus (Boophilus) microplus at 2 dip-tanks and resistance at a 3rd. It also revealed resistance in this tick to cypermethrin at 1 dip-tank and emerging resistance to chlorfenvinphos at 8 dip-tanks and resistance at 2. Rhipicephalus evertsi evertsi was susceptible to amitraz and cypermethrin at all dip-tanks, but showed emerging resistance to chlorfenvinphos at 7 dip-tanks and resistance at 4. Rhipicephalus appendiculatus was susceptible to amitraz and chlorfenvinphos at all dip-tanks and demonstrated emerging resistance to cypermethrin at 1. With the exception of R. (B.) microplus, in which emerging resistance to amitraz was detected at 1 dip-tank by the Reproductive Estimate Test, all 3 tick species at all dip-tanks at which sufficient numbers of ticks had been collected were susceptible to the 3 acaracides in both the Egg Laying Test and the Reproductive Estimate Test. The localities at which acaricide resistance was recorded were mapped.
authors.affiliation: State Veterinary Services, 23 Smith Street, Aliwal North 9750, South Africa.
authors.forename: Z
authors.initials: Z
authors.lastname: Ntondini
authors.forename: E M S P
authors.initials: EM
authors.lastname: van Dalen
authors.forename: I G
authors.initials: IG
authors.lastname: Horak
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000453:epidemiology / Q000469:parasitology*; D002709:Chlorfenvinphos / Q000494:pharmacology; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D011722:Pyrethrins / Q000494:pharmacology; D013019:South Africa / Q000453:epidemiology; D013984:Tick Infestations / Q000188:drug therapy / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D013987:Ticks / Q000187:drug effects* / Q000254:growth & development; D014052:Toluidines / Q000494:pharmacology
chemical_list: D007306:Insecticides; D011722:Pyrethrins; D014052:Toluidines; C017160:cypermethrin; C014983:amitraz; D002709:Chlorfenvinphos