DESCRIPTION

Rotavirus is a leading cause of gastroenteritis in the United States and worldwide. It is 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 >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.
• Rotavirus disease among infants and children in the Unites States has decreased significantly since the introduction of rotavirus vaccine.
• Prior to the availability of 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.

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).

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 are 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
• Rotavirus vaccine is routinely recommended for all infants; the first dose should be administered between 6 weeks and 14 weeks and 6 days of age.
• Infants should receive all doses of rotavirus vaccine prior to 8 months of age.
• Vaccine administration is contraindicated in patients with a history of intussusception or severe combined immunodeficiency (SCID).

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 interferon (IFN) induction.
• Malabsorption develops due to disruption of microvilli and decreased surface transport of digestive enzymes.