Epizoa are small parasites that live on the external surface of an animal's body. These parasites are found in a wide range of animals, including insects, birds, and mammals. There are many synonyms for epizoa, including ectoparasites, external parasites, and parasitic arthropods. Ectoparasites are parasites that attach themselves to the skin, hair, or feathers of their hosts, while external parasites are parasites that live on the surface of their host's body. Parasitic arthropods include a variety of parasitic insects, such as fleas, lice, and ticks, that feed on their hosts' blood and tissue. These parasites can cause a range of health problems for their hosts, including diseases and infections.