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

Abstract

Background Pediculosis in cattle causes significant itching, irritation and stress to the animal, often resulting in skin damage and poor coat condition. The control of bovine pediculosis in Ireland is based predominantly on commercial insecticides belonging to one of two chemical classes, the synthetic pyrethroids and the macrocyclic lactones. In recent years, pyrethroid tolerance has been reported in a number of species of livestock lice in the United Kingdom and Australia. Results In this pilot survey, lice were detected in 16 (94%) out of 17 herds visited. Two species of lice, Bovicola bovis and Linognathus vituli were identified. In vitro contact bioassays showed evidence of deltamethrin tolerance in Bovicola bovis collected from 4 farms. This was confirmed by repeatedly assessing louse infestations on treated animals on one farm. Conclusions To our knowledge this is the first record of insecticide tolerant populations of lice in Irish cattle. The results also provide new data on the species of lice infesting beef cattle in Ireland and the prevalence and control of louse infestations in Irish beef cattle herds.

Parasitological examination results of zoo animals in Germany between 2012 and 2022

“…were detected quite frequently in samples from ungulates which is comparable to the occurrence in domestic animals. In a study from Ireland on 51% of 652 examined animals chewing lice were found, whereby 88% of those cattle were infected with Bovicola bovis ( Mckiernan et al, 2021 ). Ticks found in this study were identified as I. ricinus , one of the most common ticks in Germany ( Rubel et al, 2023 ).…”

The current status and outlook for insecticide, acaricide and anthelmintic resistances across the Australian ruminant livestock industries: assessing the threat these resistances pose to the livestock sector

“…However, tolerance to deltamethrin has been reported in cattle lice in the UK and Ireland. 116,117 The timelines for these resistance outlooks for parasite control differ; for example, the dire situation for worm control in sheep compared with the lower levels of threat for sheep and cattle lice. Hence the urgency for replacement of chemical controls with the greater use of management practices and breeding programmes to reduce the reliance on chemicals may also differ across the sectors.…”

“…As highlighted above for sheep lice, the short‐medium term resistance situation for cattle lice appears to be minor compared to other parasites examined here, with no resistance reported for three chemical classes (OPs, SPs, and a BPU) and with imidacloprid yet to be introduced into this market. However, tolerance to deltamethrin has been reported in cattle lice in the UK and Ireland 116,117 …”

Ruminant health research – progress to date and future prospects, with an emphasis on Irish research

“…As this anthelmintic class is the only flukicide with efficacy against all stages of F. hepatica, resistance raises the spectre of uncontrollable liver fluke disease due to early immature stages. Tolerance to the insecticide deltamethrin has also been demonstrated in Bovicola bovis (chewing lice) (Mckiernan et al, 2021). While APR has not been documented in Ireland for a number of commercially important parasites such as Nematodirus spp.…”