Rotaviruses. Coloured transmission electron micrograph (TEM) of rotavirus particles, a common cause of intestinal infections in infants and young animals. The genetic material ribonucleic acid (RNA) is enclosed within a spherical protein shell, or capsid (blue spheres). Surface protein protruding from the capsid give the virus a spiky appearance. The virus replicates within the endothelial cells of the intestine, resulting in acute diarrhoeal disease. Infections are common in infants between 6 months and 3 years in age. Magnification: x62,500 at 6x4.5cm size.