Description

Rotavirus is a leading cause of gastroenteritis in the United States and worldwide. Characterized by frequent watery stools, illness ranges from mild diarrhea to disease complicated by severe dehydration, especially in young children.

Epidemiology

• Rotavirus is a major cause of diarrheal disease and accounts for over 200,000 deaths in children <5 years of age worldwide.
• The peak age for infection is between 6 and 24 months of age. Nearly all children acquire the virus by 5 years of age.
• In temperate climates, rotavirus activity peaks during the cold weather months but can appear year round in warmer climates.
• Transmission occurs primarily by the fecal–oral route.
• Rotavirus is highly contagious. This is due to several factors.
  • The virus has a very low inoculum of infection, requiring as few as 10 infectious particles to cause disease.
  • A high density of virus is shed into the stool during acute illness and for 1 to 3 days before and after diarrhea.
  • There is prolonged survival of the virus on a variety of environmental surfaces.
• The incubation period is 1 to 3 days.
• Prior to the rotavirus vaccine, U.S. children <5 years of age with diarrhea had a hospitalization rate of 52/10,000 person-years and an emergency department (ED) visit rate of 185/10,000 person-years.
• After the rotavirus vaccine was introduced in 2006, the hospitalization rate for all U.S. children <5 years with diarrhea fell by nearly 50% and ED visits by 25%.
• Hospitalizations for rotavirus-coded gastroenteritis among vaccinated children fell by >90%, compared to unvaccinated children.
• Rotavirus infection persists among older unvaccinated children and in the adult population.

Risk Factors

• Young infants, especially preterm infants, are at higher risk for severe dehydration and gastrointestinal (GI) complications.
• Immunocompromised patients, particularly with primary immunodeficiencies and hematopoietic stem cell transplantation are at higher risk for complications and prolonged shedding.

General Prevention

• Proper hand hygiene and cleaning of contaminated surfaces is essential to reducing person-to-person transmission.
• Contact precautions for hospitalized patients
• Two live oral vaccines are licensed in the United States:
  • Live human/bovine reassortant pentavalent rotavirus (RV5); given as a 3-dose series
  • Live human attenuated monovalent rotavirus (RV1); given as a 2-dose series
• Vaccine administration is contraindicated in patients with a history of intussusception or SCID.
• The first dose of rotavirus vaccine should be administered between 6 weeks and 14 weeks and 6 days of age.

Pathophysiology

Rotavirus infects and replicates within the enterocytes of the small bowel. Several factors appear to contribute to secretory diarrhea.

• The nonstructural protein (NSP4) acts as an enterotoxin that triggers secretory diarrhea by increasing Cl⁻ secretion and decreasing Na⁺ absorption.
• NSP4 also appears to activate the enteric nervous system, which activates a secretory state that further contributes to intestinal fluid loss.
• NSP1 is capable of inhibiting IFN induction.
• Malabsorption develops due to disruption of microvilli and decreased surface transport of digestive enzymes.

Etiology

• Rotavirus is an 11-segment double-stranded RNA virus with seven different antigenic groups (A to G).
• Types A, B, and C are responsible for most human infections, with group A being the most common.
• Group A rotavirus is further divided into multiple serotypes based on two outer capsid viral proteins: VP7 (G) and VP4 (P).