“…The cercariae encysted directly to form encysted metacercaria, when infect chicks experimentally at one day old by pipetting in the eye, they develop after 35 days post infection to obtain the adult P. hegeneri and P. megalurus from eyes (Colgan and Nollen, 1977). Ismail and Issa, 1987in Jordan, Swarnakumari and Madhavi, 1992in India, Radev et al, 2000and Diaz et al, 2002 Venzuela, they recorded that the snail Melanoides tuberculata was the intermediate host for P. gralli, P. nocturnes and P. species. They found that the snail emerged naturally cercariae which directly encysted.…”