Occurrence and effect of trematode metacercariae in two endangered killifishes from Greece.

We report digeneans (Diplostomidae, Crassiphialinae) in the endangered freshwater fishes Valencia letourneuxi and Valencia robertae, endemics of Western Greece. Digenean metacercariae occurred in two forms in the abdominal cavity, excysted and encysted, the latter attached to the gonads, liver and alimentary tract. Parasites were, using morphological and molecular techniques, identified as two representatives of Crassiphialinae, specifically part of the Posthodiplostomum-Ornithodiplostomum clade. The spatial, seasonal, and age class variation in parasite prevalence was examined. Autumn parasite prevalence varied between the six populations sampled (18.2 to 100%). Seasonal prevalence at the two sites sampled quadannually peaked in autumn and reached its lowest value in spring; prevalence increased with size to 100% in young adult fish. We did not find a correlation between prevalence and host sex. Overall parasites' weight averaged 0.64% of the host's, while parasite weight increased with host weight. A comparison of relative condition and hepatosomatic and gonadosomatic indices of infected and metacercariae-free specimens showed that infection did not have a significant effect on host body condition and reproduction. Regarding the parasite's life cycle, planorbid gastropods are proposed as potential first intermediate hosts in view of the host's diet and occurrence data of molluscs in the ecosystem. This is the first record of a diplostomid digenean in valenciid fishes and of representatives of the Posthodiplostomum-Ornithodiplostomum clade in a native Greek freshwater fish. Our findings are discussed in conjunction to fish conservation interventions, since parasites may contribute to the decline of endangered species.

Aprocta cylindrica (Nematoda) infection in a European Robin (Erithacus rubecula) in Britain.

A European Robin (Erithacus rubecula) found dead in England had marked blepharitis and periocular alopecia associated with Aprocta cylindrica (Nematoda: Aproctidae) and concurrent mixed fungal infections. Aprocta cylindrica should be considered a differential diagnosis in periocular abnormalities of robins and other insectivorous, migratory passerines in Western Europe.

Structure of the female cephalic end and cuticular ornamentations of Buckleyella buckleyi Rasheed, 1963 (Nematoda: Philometridae), as revealed by SEM.

Light and scanning electron microscopical examination of gravid females of the philometrid nematode Buckleyella buckleyi Rasheed, 1963 from the original material, collected by Rasheed from the mesentery of the type host (marine fish) Scomberoides tala off Pakistan in 1961, revealed the presence of a mound, surrounding the oral aperture and separated from the more-posterior part of body by a deep cephalic groove, and the absence of lateral cordons extending along the body. Microscopic examination also showed the presence of 3 large esophageal teeth, 8 large cephalic papillae, and a pair of amphids and transverse rod-like structures situated on irregularly scattered elevations of the body cuticle. Based on some of these features, Buckleyella Rasheed, 1963 distinctly differs from the recently established, related genus Caranginema Moravec, Montoya-Mendoza and Salgado-Maldonado, 2008.

Anisakis simplex sensu lato associated with red vent syndrome in wild adult Atlantic salmon Salmo salar in England and Wales.

Wild Atlantic salmon Salmo salar with swollen and/or bleeding vents (red vent syndrome) have been observed in rivers across England and Wales. Low numbers of salmon with this condition have previously been recorded, but reports have increased in 2006 and 2007. Affected and non-affected salmon were sampled from fish traps and their vent pathology was examined. Third stage larvae of the nematode Anisakis simplex sensu lato were observed in the tissue surrounding the vent in all affected fish. Histology of the vent showed gross lesions with an inflammatory response associated with non-encapsulated nematode worms in the connective tissue and skeletal muscle. The presence of the parasite in the unusual location of the vent areas, with associated haemorrhaging, is possibly a new emerging pathological association with the nematode A. simplex infection in Atlantic salmon. The reason for this unusual tissue tropism by larval A. simplex and the significance on already depleted salmon stocks are currently unknown.