Transmission Electron Micrograph (TEM) of Rotavirus. Group A rotavirus is endemic worldwide. It is the leading cause of severe diarrhea among infants and children, and accounts for about half of the cases requiring hospitalization. Rotavirus is usually an easily managed disease of childhood, but in 2013, rotavirus caused 37% of deaths of children from diarrhea and 215,000 deaths worldwide, and almost 2 million more become severely ill. Most of these deaths occurred in developing countries. In the United States, before initiation of the rotavirus vaccination program, rotavirus caused about 2.7 million cases of severe gastroenteritis in children, almost 60,000 hospitalizations, and around 37 deaths each year. Following rotavirus vaccine introduction in the United States, hospitalisation rates have fallen significantly. Public health campaigns to combat rotavirus focus on providing oral rehydration therapy for infected children and vaccination to prevent the disease. Magnification: unknown.