LYMNAEA CAILLIAUDI AS A NEW SECOND INTERMEDIATE HOST OF ECHINOSTOMA CAPRONI, IN EGYPT

Thirty hundred and fifty Lymnaea cailliaudi snails were collected from irrigation canals at Abou-Rawash, Giza, Egypt, during the shallow period from September to December, 1997. Encysted metacercariae of the Echinostoma caproni were collected from the internal organ and tissues of field infected Lymnaea cailliaudi with prevalence (13.7%). Two groups (3 squabs each) of one week old (Columba livia domestica) were inoculated with 6 and 15 encysted metacercariae, respectively. The  third group (3 squabs) was kept as non inoculated controls. E. caproni adults were recovered from the ileum of both experimentally inoculated groups after prepatent period of two weeks. The histopathological lesions induced by E. caproni were studied in these experimentally inoculated squabs and compared with the non inoculated controls. The inoculated jujenum (2 WPI) showed dispersion of connective tissue of submucosa by oedematus fluid. Mainly, histopathological lesions were observed in inoculated ileum (4 WPI); necrosis and slaughing of epithelial lining and haemorrhagic areas in submucosa were seen. Inflammatory reactions with lymphocytic and heterophic infiltration in lamina propria were also noticed. Necrosis and disquamation of epithelium at the tip of villi were observed. Increase numbers and activation of goblet cells with vaculation of epithelial lining villi in the mucosa of the inoculated ileum was observed.