Eprinomectin and Moxidectin Resistance of Trichostrongyloids on a Goat Farm in Austria

Abstract

Anthelmintic resistance (AR) of trichostrongyloids is widespread in Europe, but there is no up-to-date information on the spread of AR in caprine parasites in Austria. Eprinomectin (EPR) is currently the only anthelmintic drug of the macrocyclic lactones registered for goats in Europe. The aim of the present study was to gather information regarding the efficacy of anthelmintics against trichostrongyloids on a dairy goat farm in Austria with reported treatment failure of macrocyclic lactones and to determine the presence of different trichostrongyloid genera. Faecal egg count reduction tests (FECRT) using Mini-FLOTAC were performed with eprinomectin (EPR) and moxidectin (MOX). Egg count reduction, calculated with the R package egg-Counts, was 44% for EPR and 86% for MOX, confirming AR of trichostrongyloids for both compounds. The most frequently detected genus in larval cultures was Haemonchus, followed by Trichostrongylus. This is the first report of MOX resistance in caprine trichostrongyloids in Europe. Failure of EPR and MOX to control trichostrongyloid infections is a severe threat to dairy goat farming, since other compounds must not be applied in goats used for milk production. Haemonchus contortus is one of the most pathogenic parasites of small ruminants and can quickly develop AR. Thus, immediate action should be taken to slow the further spread of AR in this and other roundworm species of ruminants in Austria.

First report of eprinomectin-resistant isolates ofHaemonchus contortusin 5 dairy sheep farms from thePyrénées Atlantiques départementin France

“…Four of the 5 cases of haemonchosis presented here happened after a particularly mild winter (MeteoFrance, 2020 ), which could have allowed an increased survival of H. contortus larvae on pastures. As well as adapting to climate, H. contortus has also been adapting to ML treatments, and in addition to the present study, resistance of the Barber Pole Worm has also been recently described in sheep in southwest England (Bull et al ., 2022 ) and in goats in Austria (Hinney et al ., 2022 ).…”

Development of a three-colour digital PCR for early and quantitative detection of benzimidazole resistance-associated single nucleotide polymorphisms in Haemonchus contortus

“…The samples were derived from 26 Austrian (Tyrol, study 1, 11 farms; Salzburg, study 2, 15 farms) and 10 Italian sheep and one Austrian goat farm. On these farms FECRTs with different compounds (BZ, macrocyclic lactones (ML), monepantel; Table 3 , Table 4 , Table 5 ) had been conducted (published in ( Bosco et al, 2020 ; Untersweg et al, 2021 ; Hinney et al, 2022 )). All available samples before treatment ( n = 47) and after treatment ( n = 26) were included.…”

Correlation of Faecal Egg Counts with Clinical Parameters and Agreement between Different Raters Assessing FAMACHA©, BCS and Dag Score in Austrian Dairy Sheep

“…The fast and widespread development of anthelmintic resistances is an emerging challenge for the livestock industry [7,8]. Recent investigations conducted in Austrian sheep and goat flocks have shown a reduced efficacy in various anthelmintic drugs [9][10][11]. Therefore, the implementation and application of alternative methods and individual farm monitoring concepts are crucial to slow the development of efficacy loss for anthelmintic drugs.…”