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

Fiona Mckiernan,William Minchin,Edward O’Riordan,Annetta Zintl,Alan Dillon,Jack O’Connor,Martina Harrington

doi:10.1186/s13620-021-00198-y

Abstract

BackgroundPediculosis 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.ResultsIn 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.ConclusionsTo 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.

Highlights

Infestations of lice, known as pediculosis, are more common in cattle than any other domestic animal [1]
The percentage of sampled animals that were positive for lice on each farm ranged from 10 to 100 %. 2 species of lice were identified, the chewing louse Bovicola bovis and the sucking louse Linognathus vituli. 88 % of infected animals were infested only with B. bovis and 5 % only with L. vituli
Repeat farm visits to assess insecticide resistance in vivo On the farm where animals were sampled on four occasions to assess the efficacy of ectoparasiticide treatment in vivo, lice were present on 52 % of animals in the herd on day 0, prior to any louse treatments being administered

Summary

Introduction

Infestations of lice, known as pediculosis, are more common in cattle than any other domestic animal [1]. The only report on the prevalence of cattle lice in Ireland dates back to 1977 when Oormazdi and Baker investigated a single herd of adult cattle in a Dublinbased abattoir [15]. They recorded an infection rate of 56 % and the presence of 4 different louse species. Pediculosis in cattle causes significant itching, irritation and stress to the animal, often resulting in skin damage and poor coat condition.

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Discussion

Conclusion