Parasitology is the scientific study of parasites, organisms that live on or inside a host and benefit at the host's expense. This field examines various types of parasites, including protozoa, helminths (worms), and ectoparasites (like fleas and ticks), and their interactions with hosts, which can include humans, animals, and plants. Researchers in parasitology aim to understand the life cycles, transmission methods, and effects of parasites on their hosts. This knowledge is crucial for developing treatments and prevention strategies for parasitic infections, which can cause significant health issues and economic losses worldwide.