Rotaviruses. Coloured transmission electron micrograph (TEM) of a cluster of rotaviruses. They are probably the most common viruses to infect humans and animals. Rotaviruses get their name from their wheel-like appearance. They contain RNA genetic material. These viruses are associated with gastroenteritis and diarrhoea in humans and other mammals. Typically they infect the intestines in children of age 6 months to 3 years. The diarrhoea results in fluid loss and dehydration, and the viruses are spread in faeces. Magnification: x54,000 at 6x7cm size. x90,000 at 4x5"~LANDSCAPE"