Host-parasite interaction refers to the relationship between a host organism and a parasite that lives within or on the host. Parasites can be viruses, bacteria, fungi, protozoa, or multicellular organisms such as worms or mites. The interaction between the host and parasite can range from mutualism, where both organisms benefit, to parasitism, where the parasite benefits at the expense of the host. Research in this area explores how parasites interact with their hosts, including mechanisms of infection, transmission, and immune responses. Understanding host-parasite interactions is crucial for developing strategies to control parasitic diseases and prevent their spread. This research can also provide insights into broader biological processes such as immune function, evolution, and ecology.