Parasitology is the study of parasites, organisms that live on or in a host and benefit at the host's expense. This field encompasses various types of parasites, including protozoa, helminths, and ectoparasites, and examines their life cycles, interactions with hosts, and the diseases they cause. Researchers in parasitology aim to understand the biology and ecology of these organisms to develop effective treatments and control measures. This knowledge is crucial for public health, as many parasitic infections, such as malaria and schistosomiasis, pose significant health risks worldwide.