Ectoparasitism is a type of symbiotic relationship where parasites live on the exterior of a host organism. These parasites, such as fleas, ticks, and lice, feed on the host's blood or skin, often causing discomfort or disease. Ectoparasites can affect a wide range of animals, including humans, and can transmit various pathogens. Unlike endoparasites, which live inside the host, ectoparasites remain on the surface. This external lifestyle allows them to reproduce quickly and spread easily. Ectoparasitism can lead to health issues for the host, including irritation, allergic reactions, and infections.