The present study evaluated the phylogenetic relationships among the six valid species of catfish of the genus Hypophthalmus , estimated the divergence times among the different taxa and assessed the processes that influenced the evolution of the group. All the phylogenetic analyses, based on 6803 base pairs, including three mitochondrial and seven nuclear markers, support the monophyly of Hypophthalmus , and the arrangement o...

The “dilution effect” concept in disease ecology offers the intriguing possibility that clever manipulation of less competent hosts could reduce disease prevalence in populations of more competent hosts. The basic concept is straightforward: host species vary in suitability (competence) for parasites, and disease transmission decreases when there are more incompetent hosts interacting with vectors or removing free‐living stage...

The pathological changes induced by an infection of Diphyllobothrium dendriticum (Nitzsch, 1824) plerocercoids in powan, Coregonus lavaretus (L.), from Loch Lomond, Scotland, were assessed using immunohistochemical and ultrastructural techniques. In a sample of 26 powan, the occurrence of encysted plerocercoids of D. dendriticum on the outer surface of the stomach was 38.5% ( n = 10) with the number of cysts ranging from 4 to...

Immunohistochemical examination of the galaninergic and the diffuse endocrine systems of the alimentary canal of three catfish species, Ameiurus melas, Silurus glanis and Clarias gariepinus showed the presence of galanin‐like immunoreactive endocrine cells in the stomachs and the proximal intestines and a galanin‐like immunoreactivity within the enteric intramural neurons. The three species differed notably in the relative abu...

A histopathological and immunohistochemical study on the intestines of 45 specimens of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), from Loch Awe, Scotland, revealed a number of cellular deviations in individuals naturally infected with the pseudophyllidean cestode Eubothrium crassum (Bloch, 1779). Twenty‐five individuals (55.5%) were infected with an average worm burden of 18.84 ± 4.06 (mean ± SE) cestodes per host (r...