Scanning electron micrograph (SEM) of the comma- shaped bacterium, Vibrio cholerae, cause of cholera. The bacterium moves by means of a single terminal flagellum (seen here). The spread of cholera is associated with poor sanitation and water supplies contaminated by faeces from a patient. The bacteria lodge primarily in the small intestines causing inflammation, vomiting, diarrhoea and ultimately dehydration. Mag:X10,000 (5x3), X2,850 (35mm).