Rotaviruses are transmitted via the fecal-oral route. During rotavirus infection large numbers of viral particles are shed in the stool. Rotavirus spreads easily under conditions of overcrowding and poor hygiene. In developing countries and crowded day care centers children are exposed to rotavirus in infancy. Rotavirus is a common nosocomial infection in pediatric settings.
Rotaviruses are seasonal in northern climates, with peaks of disease in the cooler winter months.
In the US the peak incidence of rotavirus disease begins in the fall in the southwest and spreads eastward so that by late winter and spring infection peaks in the Northeast. Year round rotavirus infection occurs in tropical countries. Rotavirus Groups 1. There are 3 rotavirus Groups, A, B, C which are both antigenically and genetically distinct. The inner capsid protein, VP6 is the common or Group specific antigen.