False colour transmission electron micrograph (TEM) of a section of human intestine showing schizonts of Cryptosporidia, a parasitic sporozoan (protozoan) causing acute diarrhoea in man, which can arise as a secondary, opportunistic infection in persons suffering from AIDS (Acquired Immune Deficiency Syndrome). The circular schizonts divide asexually to give rise to numerous smaller cells known as schizozoites. The AIDS virus depletes the victim's immune system by somehow destroying the population of T4 inshelperins lymphocytes that trigger the destruction of foreign microorganisms that invade the body. Magnification: X 1,600 at 35mm size. Original is BW print m112/020.