Occurrence of Helminths in the Great Cormorants, Phalacrocorax carbo, in Qena, Egypt

Three adult female cormorants, Phalacrocorax carbo, were found dead in Qena province, Egypt in December 2016. They were immediately sent to the Laboratory in Faculty of Science, South Valley University, Egypt, for necropsy. Apparently, the birds had no gross lesions or suffered from injured or damaged tissue. Complete evisceration of internal organs was performed, and birds were subjected to a full parasitological examination for the detection of helminths. Helminthiasis was only detected in the gastrointestinal tracts. Among the recovered helminths, three trematodes, one tapeworm, and three nematode species were found. Digeneans were identified as Clinostomum complanatum (n=3; at the first part of the oesophagus), Ribeiroia ondatrae (n=2; at the middle part of the oesophagus), and Paryphostomum radiatum (n=3; in the small intestine). The revealed cestodes species (n=one; in the small intestine) were identified as Paradilepsis scolecina. Lastly, the recovered nematodes (n=3; in the stomach) were identified as Contracaecum rudolphii, Contracaecum microcephalum, and Contracaecum chubutensis. It was noted that mixed infection of all helminth species was found in a single bird. Moreover, another bird also presented with mixed infection of Contracaecum spp. and digeneans. Histopathological examination revealed leucocytic infiltration surrounding the embedded digeneans, hyperplasia of the proventricular wall, as well as necrosis with remnants of degenerated trematodes. To the best of the authors' knowledge, this is the first study revealing Clinostomum complanatum, Ribeiroia ondatrae, Paryphostomum radiatum, Paradilepsis scolecina, Contracaecum rudolphii, Contracaecum microcephalum, and Contracaecum chubutensis in the great cormorant, Phalacrocorax carbo, in Egypt.