Parasitology is the study of biological parasites and parasitic diseases, involve the distribution, biochemistry, physiology, molecular biology, ecology, evolution and clinical aspects of parasites which includes the host response to agents. Parasites are the organisms that exists or present in the another organism and survive by feeding off host it means that a parasite is an organism which is metabolically dependent on another organism for its survival. It traditionally includes the study of three major groups of animals that are parasitic protozoa, parasitic helminths (worms), and arthropods it may directly cause the diseases or acts as vectors of various pathogens.