Images Dated 11th April 2003

Coloured SEM of a human head louse on hair shafts

Head louse. Coloured scanning electron micrograph (SEM) of a human head louse (Pediculus humanus capitis) clinging to human hair. The head louse inhabits the hair of the head, glueing its eggs (called nits) to the shafts of individual hairs. It lives on blood, which it sucks from the scalp. The wounds left by the lice cause intense itching, which can lead to dermatitis and impetigo (a bacterial infection of the skin). The problems are compounded by reflex scratching of the bites. The lice can spread from head to head by close contact. Nits and lice can be killed by washing the hair with special medicated shampoos. Magnification: x44 at 6x7cm size. x106 at 7x5.5ins

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

F/col TEM of Haemophilus influenzae

False-colour transmission electron micrograph (TEM) of Haemophilus influenzae (Pfeiffer's bacillus), a Gram negative, non-motile, non- sporing species of bacilli (rod-shaped bacteria). H. influenzae is exclusively a parasite of man, living in the upper respiratory tract of healthy individuals. Most sub-species are non-capsulate bacteria, but there are 6 types of capsulated strains (types a to f), of which type b is responsible for numerous incidences of bacterial meningitis in young infants. Other type b diseases include epiglottitis, a potential cause of fatal obstruction in the airways. Magnification: x16, 000 at 35mm size, x32, 000 at 6x7cm size

© CNRI/SCIENCE PHOTO LIBRARY