Posthodiplostomum cuticola(Digenea: Diplostomatidae) in intermediate fish hosts: factors contributing to the parasite infection and prey selection by the definitive bird host

Abstract

Infection parameters of Posthodiplostomum cuticola, a digenean parasite with a complex life-cycle, were investigated in fish (the second intermediate host) from 6 floodplain water bodies over 2 years. A broad range of factors related to abiotic characteristics of localities, density of the first intermediate (planorbid snails) and definitive (wading birds) hosts and fish community structure were tested for their effects on P. cuticola infection in juvenile and adult fish. Characters of the littoral zone and flood duration were found to be important factors for the presence of the first intermediate and definitive hosts. Visitation time of definitive bird hosts was also related to adult fish host density. Localities with P. cuticola infected fish were visited by a higher number of bird species. Infection of P. cuticola in fish and similarities in infection among fish host assemblages were correlated with fish host density and fish species composition. Parasite infection in both adult and juvenile fishes was associated with the slope of the bank and the bottom type, in particular in juvenile fish assemblages with snail host density. We conclude that habitat characteristics, snail host density and fish community structure contribute significantly to P. cuticola infection in fish hosts.

Seasonal occurrence of some larval stages of endoparasites in three cyprinids from the Nwanedi-Luphephe dams, the Limpopo River System, South Africa

“…may also be infl uenced by the type of habitat. Lentic ecosystems provide specifi c conditions, such as the higher water temperature and lower water currents (Ondračková et al, 2004), which facilitates concentration of the fi rst and second intermediate hosts, thus increasing the probability of the cercariae locating its host. In addition, these conditions make the second intermediate host more vulnerable to predation by piscivorous birds.…”

Metacercariae of Clinostomum schizothoraxi Kaw, 1950 (Digenea: Clinostomatidae) in Carassius carassius (Linnaeus) under different environmental conditions

“…Snail density and visitation of bird definitive host often play important roles for the transmission of larval digeneans infecting fish hosts , Sandland et al 2001, Ondračková et al 2004). Furthermore, the distribution and abundance of macrophytes are usually thought to be primarily a function of abiotic factors, including depth, nutrients, current, waves and light (Wetzel 2001).…”

“…In view of the fact that the transmission of trematode infections in a water body is affected by the occurrence and density of intermediate snail hosts (Ondračková et al 2004), a follow-up study was conducted during the second year (June 2007to May 2008 to examine the density profiles of intermediate mollusc hosts in the three lakes. To measure the variation in density of gastropod snails, five substrate hauls were taken monthly from each lake.…”

“…Various studies have suggested that changes in population densities of some larval fish trematodes can be correlated with changes in abiotic characteristics and population densities of the snail intermediate hosts , Sandland et al 2001, Flores and Semenas 2002, Ondračková et al 2004, Lafferty et al 2005, Johnson et al 2010.…”

Schistosomatoidea and Diplostomoidea

“…It is a common parasite of freshwater fi shes; it has been found in over 70 fi sh species in Palearctic region. Within the life cycle, planorbid snails ( Planorbis planorbis , Planorbarius corneus ) serve as the fi rst intermediate host [ 193 ]. There is a broad range of second intermediate hosts, but the members of Cyprinidae are the most frequently attacked fi shes; in some cases (e.g., in Croatia) 100 % prevalence of infection has been recorded [ 194 ].…”