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Research article - Peer-reviewed, 2016

Assessment of flukicide efficacy against Fasciola hepatica in sheep in Sweden in the absence of a standardised test

Novobilský, Adam; Solis, Natalia Amaya; Skarin, Moa; Hoglund, Johan


Anthelmintic resistance (AR) toFasciola hepaticais emerging worldwide. Recently, AR to the adulticide compound albendazole (ABZ) was shown in Argentina and Spain. In Sweden, ABZ treatment failure againstF.hepaticawas first reported in sheep in 2012. The present study tested the efficacy of ABZ and triclabendazole (TCBZ) in sheep naturally infected withF.hepaticausing a combination of three different diagnostic methods: faecal egg counts (FEC), coproantigen ELISA (cELISA) andFasciolaegg hatch test (FEHT). Two deworming trials, in November 2014 and January 2015, were performed on two sheep farms (farms A and B) in south-western Sweden. Except ABZ in November, treatment with ABZ or TCBZ achieved sufficient efficacy (97–100%) against adultF.hepaticaon farm A. In contrast, ABZ treatment failed in the sheep flock on farm B, despite low initial faecal egg output. On farm B, ABZ efficacy based on FEC was 67% (95% CI: 35–84) and four of eight ewes tested were coproantigen-positive 21 days post-treatment. Ovicidal activity of ABZ againstFasciolaeggs in isolates from both farms and one additional bovine isolate were tested by FEHT to exclude the presence of juvenile flukes and other factors such as dosing failure and poor quality of drug product. Irrespective of drug trial, data from FEHT showed significantly lower ovicidal activity of ABZ for the ovine farm B isolate than for the isolate from farm A. This confirms that the low efficacy of ABZ in sheep flock B was associated with ABZ resistance. Overall, the usefulness of three complementary methods for detection of ABZ resistance in the field was demonstrated.


Albendazole; Coproantigen ELISA; Egg hatch test; Faecal egg count; In vitro; Liver fluke; Resistance

Published in

International Journal for Parasitology: Drugs and Drug Resistance
2016, Volume: 6, number: 3, pages: 141-147