Rumen fluke: past, present and future

Abstract

There has been a rapid expansion in the range of the rumen fluke species Calicophoron daubneyi over the last decade in the UK and Ireland, preceded by a similar increase in France from 1990. The reasons for this are unclear, but this species of rumen fluke utilises the mud snail, Galba truncatula, as its intermediate host, in contrast to other paramphistomes, for which aquatic snails are the commonest intermediate hosts. G. truncatula has a cosmopolitan distribution in temperate regions, and is also an intermediate host for Fasciola hepatica. Paramphistomosis has two manifestations in domestic ruminants: 1) a potentially fatal, acute disease with sudden onset of watery diarrhoea and weight loss that results from extensive pathology in the duodenum, where the juvenile flukes develop; and 2) colonisation of the rumen by adult flukes, without apparent detrimental effects on the host. Rumen fluke infections can be diagnosed through faecal samples, examined for either eggs or immature fluke or both. Oxyclozanide is the only available anthelmintic that is effective against both adult and immature rumen fluke. While prompt treatment of acute larval paramphistomosis is essential, the rationale for treating adult rumen fluke infections is less clear.