Influence ofTriaenophorus nodulosusplerocercoids (Cestoda: Pseudophyllidea) on the occurrence of intestinal helminths in the perch (Perca fluviatilis)

Abstract

AbstractConcurrent infections of helminths in vertebrates are widespread and may demonstrate synergistic, antagonistic or negligible levels of interactions between species that share a common site. However, indirect interactions between species that occur in different organs of a host are poorly documented, particularly in fish. Plerocercoids ofTriaenophorus nodulosusare common liver infections of European perch (Perca fluviatilis). These larval cestodes cause extensive liver damage, resulting in systemic pathologies that include alteration of the physiochemical environment of the intestine. Perch harbour a wide range of intestinal helminths whose occurrence may be potentially influenced by the concurrent presence ofT. nodulosusplerocercoids. The present study, using an existing dataset, investigated the effects ofT. nodulosuson the infection levels of four common perch helminths –Acanthocephalus lucii, Camallanus lacustris, Proteocephalus percaeandBunodera luciopercae. The prevalences ofA. luciiandC. lacustriswere significantly reduced in fish infected byT. nodulosus, although the mean intensity of infections remained unaffected for any helminth species, while the mean abundance ofC. lacustriswas significantly reduced in plerocercoid-affected perch. Differences in site selection and individual interactions between the four helminth species in the intestine ofT. nodulosus-infected and non-infected perch were rarely observed.