Rotavirus may be a genus of double-stranded RNA viruses within the family Reoviridae. Rotaviruses are the foremost common explanation for diarrhoeal disease among infants and young children. Nearly every child within the world is infected with rotavirus a minimum of once by the age of 5. Immunity develops with each infection, so subsequent infections are less severe; adults are rarely affected. The virus is transmitted by the fecal-oral route. It infects and damages the cells that line the tiny intestine and causes gastroenteritis (which is usually called "stomach flu" despite having no reference to influenza). Although Rotavirus was discovered in 1973 by Ruth Bishop and her colleagues by electron micrograph images and accounts for about one third of hospitalisations for severe diarrhoea in infants and children, its importance has historically been underestimated within the general public health community, particularly in developing countries. In addition to its impact on human health, rotavirus also infects other animals, and is a pathogen of livestock.