The study of parasitology helps the students to have a good grasp of what a particular parasite is all about and they can assess its impact and thus determine what kind of control programme may be needed. The present books not only cover all the important topics that is required in a textbook, but also introduces the reader with latest developments and information's. This book is prepared by keeping in view the requirements of undergraduate and postgraduate students of several universities. Topics are address with terminology that is as simple as possible, so that students will not be impeded by arcane words but will be able to see what the phenomenon is without difficulty.