Pyrethroid resistance in Australian field populations of the sheep body louse, Bovicola (Damalinia) ovis

Abstract

Synthetic pyrethroid (SP) resistance has developed in Australian field populations of the sheep body louse, Bovicola (Damalinia) ovis. Laboratory bioassays were used to measure the susceptibility of lice to cypermethrin and the other registered SPs. Results of these bioassays indicated resistance to cypermethrin, deltamethrin, cyhalothrin and alphacypermethrin. So far, high-level resistance has been diagnosed in only a few strains. The toxicological responses of these strains were clearly separated from those of the majority of louse strains tested. Furthermore, these strains had survived immersion in commercial SP dips. The level of resistance described in some strains was sufficient to cause pour-on products to fail despite the fact that the LC50s of these strains fell within the normal range of field responses.

Essential oils in the management of the donkey louse, Bovicola ocellatus

“…Within the last 25 years, widespread resistance to pyrethroid insecticides has developed in Australian populations of the sheep chewing louse Bovicola ovis . High levels of pyrethroid tolerance have also been found in populations of Bovicola infesting cattle and donkeys .…”

A pilot study on the prevalence of lice in Irish beef cattle and the first Irish report of deltamethrin tolerance in Bovicola bovis

“…The widespread (over)use of pyrethroid-based products has led to the emergence of deltamethrin-resistant B. bovis lice in the UK [ 20 ], cypermethrin, alphacypermethrin and deltamethrin- resistant B. ovis lice in Australia [ 16 , 32 , 33 ] and cypermethrin and permethrin resistant B. ocellatus lice in the UK [ 17 ].…”

“…In recent years, concerns have been raised globally over the development of insecticide resistance in louse populations of livestock associated with the widespread use of ectoparasiticides in agricultural production. To date, resistance has been reported in a number of species of lice including Bovicola ovis, Bovicola ocellatus, Haematopinus tuberculatus and Haematopinus suis [ 16 – 19 ]. In 2015, Sands and colleagues published the first reports of deltamethrin tolerance in the cattle louse Bovicola bovis in the UK [ 20 ].…”

Navigating the resistance: Current perspectives on ectoparasite control in veterinary medicine

“…According to the conducted studies, the prolonged usage of ectoparasites of the same class over an extended period of time is a risk factor for the emergence of ectoparasitic resistance in Australia (Levot et al, 1995;Wilson et al 1997;Jonsson et al, 2000). It can also be an issue when identical products are used to control various ectoparasites and the epidemiology of different types of infestations, such as resistance in external parasites when macrocyclic lactone anthelmintics are used (FAO, 2004).…”