Statistics from Altmetric.com
CATTLE and sheep farmers across the UK are concerned that it is becoming increasingly difficult to control the liver fluke, Fasciola hepatica, in their livestock. There is considerable variability in the incidence of clinical fasciolosis between years but, for the past 15 years, the overall trend has definitely been upwards, while the area where fasciolosis risk is significant has increased (van Dijk and others 2010). At least in part, these trends can be explained by changes in weather patterns, which increase the abundance of infective stages at pasture and/or the mud snail intermediate host (Caminade and others 2015). Meanwhile, in sheep flocks, resistance to triclabendazole, the only flukicide with activity against immature and adult flukes, is limiting treatment options (Fairweather 2011, Daniel and others 2012).
Flukicide resistance has, to our knowledge, not yet been diagnosed in cattle. This may be related to the less frequent application of flukicides to cattle herds but, as beef cattle may well ingest resistant worms when co-grazing with sheep, may also reflect the lack of a validated diagnostic test applicable under field conditions. Developing and validating such a test for cattle (based on composite egg count and/or coproantigen ELISA) is one of the objectives of a new Biotechnology and Biological Sciences Research Council (Dairy and Beef Levy Board) co-funded research project. This initiative is also working on a rapid diagnostic test to distinguish between liver fluke and rumen fluke infections, thereby addressing important diagnostic gaps in beef herds (Charlier and others 2014a).
Once parasite presence …