Determination of the prevalence and intensity of Fasciola hepatica infection in dairy cattle from six irrigation regions of Victoria, South-eastern Australia, further identifying significant triclabendazole resistance on three properties

Jane M Kelley; Vignesh Rathinasamy; Timothy P Elliott; Grant Rawlin; Travis Beddoe; Mark A Stevenson; Terry W Spithill

doi:10.1016/j.vetpar.2019.109019

Determination of the prevalence and intensity of Fasciola hepatica infection in dairy cattle from six irrigation regions of Victoria, South-eastern Australia, further identifying significant triclabendazole resistance on three properties

Vet Parasitol. 2020 Jan:277:109019. doi: 10.1016/j.vetpar.2019.109019. Epub 2019 Dec 31.

Authors

Jane M Kelley¹, Vignesh Rathinasamy¹, Timothy P Elliott², Grant Rawlin³, Travis Beddoe¹, Mark A Stevenson⁴, Terry W Spithill⁵

Affiliations

¹ Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Bundoora Victoria 3083, Australia.
² Invetus, Armidale NSW 2350, Australia.
³ Department of Jobs, Precincts and Regions, Centre for AgriBioscience, La Trobe University, Bundoora Victoria 3083, Australia.
⁴ Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville Victoria 3010, Australia.
⁵ Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Bundoora Victoria 3083, Australia. Electronic address: t.spithill@latrobe.edu.au.

PMID: 31918044
DOI: 10.1016/j.vetpar.2019.109019

Abstract

Fasciola hepatica (liver fluke) is a widespread parasite infection of livestock in Victoria, South-eastern Australia, where high rainfall and a mild climate is suitable for the main intermediate host Austropeplea tomentosa. The aims of this study were to quantify the prevalence and intensity of F. hepatica in dairy cattle in the irrigated dairy regions of Victoria and determine if triclabendazole resistance was present in infected herds. Cattle in 83 herds from the following six irrigation regions were tested for F. hepatica: Macalister Irrigation District (MID), Upper Murray (UM), Murray Valley (MV), Central Goulburn (CG), Torrumbarry (TIA) and Loddon Valley (LV). Twenty cattle from each herd were tested using the F. hepatica faecal egg count (FEC) as well as the coproantigen ELISA (cELISA). The mean individual animal true prevalence of F. hepatica across all regions was 39 % (95 % credible interval [CrI] 27%-51%) by FEC and 39 % (95 % CrI 27%-50%) by cELISA with the highest true prevalence (75-80 %) found in the MID. Our results show that 46 % of the herds that took part in this study were likely to experience fluke-associated production losses, based on observations that herd productivity is impaired when the true within-herd prevalence is > 25 %. Using the FEC and cELISA reduction tests, triclabendazole resistance was assessed on 3 herds in total (2 from the 83 in the study; and 1 separate herd that did not take part in the prevalence study) and resistance was confirmed in all 3 herds. This study has confirmed that F. hepatica is endemic in several dairy regions in Victoria: triclabendazole resistance may be contributing to the high prevalence in some herds. From our analysis, we estimate that the state-wide economic loss associated with fasciolosis is in the order of AUD 129 million (range AUD 38-193 million) per year or about AUD 50,000 (range AUD 15,000-75,000) per herd per year.

Keywords: Dairy cattle; Fasciola hepatica; Liver fluke; Prevalence; Triclabendazole resistance; cELISA.

MeSH terms

Animals
Antiplatyhelmintic Agents / pharmacology
Cattle
Cattle Diseases / epidemiology*
Cattle Diseases / parasitology*
Dairying
Drug Resistance*
Fasciola hepatica / drug effects*
Fascioliasis / drug therapy
Fascioliasis / prevention & control
Fascioliasis / veterinary
Prevalence
Triclabendazole / pharmacology
Victoria / epidemiology

Substances

Antiplatyhelmintic Agents
Triclabendazole