Rotaviruses. Coloured transmission electron micrograph (TEM) of rotaviruses (green). They are probably the most common viruses to infect humans and animals. Rotaviruses get their name from their wheel-like appearance. They contain RNA (ribonucleic acid) 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. x175,000 at 7x9.5"~PORTRAIT"