False-colour scanning electron micrograph (SEM) of a pair of adult male & female blood flukes, Schistosoma mansoni, the cause of schistosomiasis (bilharzia). The smaller female (cylindrical) schistosome lies in a groove (gynaecophoric canal) on the larger male fluke & together they inhabit blood vessels of small intestine, causing dysentery & diarrhoea. Their spiked eggs cause anaemia, inflammation & tissue scarring. The circariae (larvae) develop in freshwater snails (intermediate host) & are released into the water. Humans (final host) are infected while bathing or working in contaminated water. Magnification: X 11 at 35mm size. Species occurs in Africa, West Indies and South &