Loose (plural: lice) is the common name for members o the order Phthiraptera, which conteens nearly 5,000 species o weengless insect. Lice are obligate parasites, livin freemitly on wairm-bluidit hosts which include every species o bird an mammal, except for monotremes, pangolins, baukies an cetaceans. Lice are vectors o diseases such as typhus.