NATS 1540 Lecture Notes - Lecture 53: Crab Louse, Head Louse, Body Louse
31 May 2020
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Document Summary
Only two species are parasitic for humans: pediculus humanis var corporis (body louse), pediculus humanis var capitus (head louse) and phthirus pubis (pubic or crab louse) Fertilized female lays 250-300 eggs over 20-30 days and dies. Eggs are firmly glued to body hairs or fibers of clothing (nits) 7-10 days later, nymphs emerge and must feed. Lice pierce the skin, inject saliva, defecate and obtain blood meal. Hypersensitivity reactions to antigens in saliva causes pruritic papules. Epidemiology: serves as a vector worldwide for other infections. Pediculosis corporis: transmits because of overcrowding and poor sanitation. Lays eggs in seams of clothing rather than skin. Nits in clothing for up to 1 month. Phthirus pubis: transmitted via sexual or close body contact. It lives in pubic hair, but also eyebrows, eyelashes, axillary hair, coarse hair on back and chest. Up to 1/3 of people with pubic lice have other sexually transmitted diseases.
