Caption

Shigella dysenteriae bacteria. Coloured scanning electron micrograph (SEM) of Shigella dysenteriae bacteria, the cause of dysentery in humans. Several of the rod-shaped, non-motile, Gram- negative bacterial cells can be seen. Dysentery affects mainly the large intestine and varies in severity from a mild attack of diarrhoea to an acute infection. Until the introduction of sulphonamide drugs in the 1930s it was a world- wide killer disease. It still affects the young, elderly and malnourished. Infection is spread by flies, direct contact, and water contaminated by faeces containing the bacillus. Magnification: x14,600 at 6x7cm size.