Infection due to the rotaviruses is a common cause of diarrhea.

Rotaviruses are RNA viruses that infect epithelial cells in intestinal villi. Transmission is primarily through the fecal-oral route. The pathogenesis of diarrhea after infection is not known with certainty, but is thought to be a combination of malabsorption, the action of a viral enterotoxin, and increased fluid secretion into the intestine.

Infection due to the rotaviruses is the most common cause of severe diarrhea in infants and young children worldwide. Most children are infected within the first few years of life. Infection provides some protection against reinfection, but reinfection is still possible throughout life. Infection later in life is typically associated with less severe symptoms.

Patients present with symptoms of gastroenteritis including diarrhea and vomiting.

• In children, vomiting typically occurs first, may be associated with fever, and lasts about 2 days. Watery diarrhea then develops and lasts for a few days. Severe dehydration may result, especially in infants younger than 2 years old.
• In adults, the symptoms are similar, although usually less severe. Abdominal pain may be present. Fever is not common.

Virus may be detected in stool for up to 10 days after resolution of symptoms (viral RNA may be detected by polymerase chain reaction [PCR] for weeks after resolution of symptoms), and prolonged viral shedding may be seen in children, the immunocompromised, and elderly patients.

Immunocompromised children and adults can have particularly severe symptoms or develop chronic diarrhea due to rotavirus infection. One report of a cluster of 4 cases in solid organ transplant recipients noted that the diarrhea (up to 10 episodes per day) lasted between 4 and 12 days. One patient developed such severe diarrhea that he lost 3 kg within 24 hours, leading to hypotension. One patient developed colonic ulcers (which caused significant blood loss).

In the clinical setting, determining whether a case of gastroenteritis is due to a rotavirus or another infectious agent is usually not possible. Specific diagnosis is not usually necessary, as there is no specific antiviral therapy available, and treatment is supportive and focused on preventing dehydration.

Antigen testing or PCR testing of stool is available and used mostly for epidemiologic study, to reduce the unnecessary use of antibiotics, or to establish a diagnosis in immunocompromised patients. Two rotavirus vaccines are available in the United States and have been found to decrease severe, dehydrating rotavirus disease.