Rotavirus diarrhea is caused by infection with Rotavirus, a double-stranded RNA virus belonging to the Reoviridae family. It primarily affects children under five years old, causing severe watery diarrhea, vomiting, and dehydration. The virus infects the mature enterocytes of the small intestine, leading to malabsorption and osmotic diarrhea. Rotavirus is the leading cause of severe gastroenteritis in infants and young children worldwide. Diagnosis is confirmed by detecting viral antigens in stool. Vaccination has significantly reduced the incidence and severity of rotavirus infections.

Reference: Nelson Textbook of Pediatrics, Kliegman et al., 21st Edition.