Fluke diseases of UK ruminant livestock Part 1: Life cycles, economic consequences and diagnosis

Abstract

Parasitic trematodes are well-recognised, worldwide causes of production loss in cattle and sheep. Fasciola hepatica is the most important trematode parasite of UK livestock, although Dicrocoelium dendriticum and Paramphistomum cervi also occur. Over the past decade definite changes have been recorded in the regional prevalence, seasonality and severity of disease caused by fluke infections of UK livestock. In the case of fascioliasis, surveillance data show a particularly high national disease prevalence between 2000 and 2003, and again during the first quarter of 2008, with concurrent spread from traditional fluke areas in western UK to normally drier and fluke-free eastern districts. Fascioliasis is now considered to be endemic throughout the UK. These epidemiological changes have been related to increased rainfall, or localised flooding, prompting debate about deleterious effects of climate change. As a consequence effective management of fluke diseases has become problematic in traditional fluke areas, leading to serious production loss in sheep and cattle, while in eastern districts, disease outbreaks have been unexpected, also resulting in production loss and welfare concern.