Human body louse. Light micrograph of a female of the human body louse, Pediculus humanus, the carrier of serious diseases such as typhus and relapsing fever. This parasite lives in clothing, fastening itself to fibres using the hook-shaped claws on its legs. The body louse only moves onto the skin when it feeds, drinking blood using specially-shaped mouthparts. The louse cannot obtain all the vitamins it requires from blood, instead relying on symbiotic bacteria that live within its body. Successive louse generations follow each other about every three weeks, each female laying about 200-300 eggs. Magnification: x7.5 at 35mm size.