Host specimens were randomly sampled from the farms of Kharibari and Canning stations of Sundarbans region, West
Bengal and brought alive to the laboratory or in moribund condition. In the laboratory the gut of the shrimps were
removed aseptically with fine forceps, gut materials were scrapped out on glass slides in 0.8% saline and examined
under phase contrast microscope for detection of fresh gamonts. The smeared slides are air-dried, fixed in methanol
and stained in Giemsa for permanent preparation. Measurements of the trophozoites were taken with the aid
of a calibrated ocular micrometer. All measurements are presented in lm as mean (±) SD followed in parentheses