Coloured scanning electron micrograph (SEM) of Vibrio cholerae bacteria. These are Gram-negative, enteric, facultatively anaerobic, curved (comma-shaped) rod prokaryotes. Vibrio cholerae causes Asiatic cholera. The bacterium lives naturally in brackish or coastal saltwater. A person can get cholerae by drinking water or eating food contaminated with the cholera bacterium. The bacteria infects the intestine and increases mucous production causing diarrhoea and vomiting which result in extreme dehydration and possible death. In an epidemic, the source of the contamination is usually the faeces of an infected person that contaminates water or food. Magnification: x10,000 when shortest axis printed at 25 millimetres.