Rotavirus Infection

Rotavirus is a leading cause of severe acute gastroenteritis in infants and young children worldwide. It is a double stranded ribonucleic acid virus of the Reoviridae family. It spreads by the faecal oral route and is highly infectious at a very low infectious dose.

Before effective oral vaccination, it caused a large global burden of childhood mortality from dehydration. Vaccination has dramatically reduced both incidence and severity in populations with high vaccine coverage.

Pathophysiology

The virus infects and destroys mature enterocytes at the tips of the small intestinal villi. This impairs absorptive function and disaccharidase activity.

The virus also produces a specific enterotoxin (NSP4) that directly stimulates secretory diarrhoea. Together these cause the characteristic severe, high volume watery diarrhoea and a significant dehydration risk. The risk is highest in young, immunologically naive children with their first infection.

The incubation period is short, at one to three days. Fever and vomiting follow, typically preceding the watery diarrhoea by around 24 hours.

The diarrhoea is frequently profuse and prolonged, commonly lasting five to seven days. It is the principal driver of dehydration risk, particularly in young infants with limited physiological reserve.

Severity is typically greatest with first infection in infants and young children, generally between six months and two years of age. Illness is progressively milder on reinfection later in childhood and adulthood, as partial protective immunity develops after initial infection. This pattern explains the age distribution of severe disease.

Signs of significant dehydration are the principal clinical concern and the key focus of ongoing assessment throughout the illness:

• Reduced urine output
• Lethargy
• Sunken eyes and fontanelle (in infants)
• Reduced skin turgor
• In severe cases, signs of hypovolaemic shock

Diagnosis is generally clinical in a young child with fever and vomiting followed by watery diarrhoea. This is particularly so during the recognised seasonal peak period in temperate climates. Typical, self limiting, community managed presentations need no routine laboratory confirmation.

Stool antigen testing (enzyme immunoassay) or polymerase chain reaction testing gives rapid confirmation where pursued. It is particularly relevant in hospital for infection control, and where diagnostic clarification would influence management.

Confirmed cases can then be cohorted and isolated appropriately. This limits nosocomial transmission, given the high infectivity of this virus within healthcare and childcare settings.

Assess dehydration severity throughout the illness, using standard clinical tools and criteria as for gastroenteritis generally. Dehydration is the principal driver of morbidity and the key determinant of management approach and setting of care.

Management is entirely supportive. It centres on oral rehydration therapy using a low osmolarity oral rehydration solution given in small, frequent volumes. This is effective for the great majority of presentations, even with the typically high volume diarrhoeal losses, provided rehydration is initiated promptly and administered appropriately.

Intravenous rehydration follows standard paediatric fluid calculation principles based on estimated deficit, maintenance requirement and ongoing losses. It is reserved for:

• Severe dehydration
• Persistent significant vomiting preventing adequate oral intake
• Failure of oral rehydration attempts

Monitor and correct electrolyte disturbance carefully, given the significant volume of fluid loss that can occur with this infection.

Ondansetron, at the weight based paediatric doses detailed under gastroenteritis generally, is a useful adjunct. It reduces vomiting and supports successful oral rehydration in the emergency department or acute assessment setting. It avoids intravenous access in an appropriate proportion of children where vomiting is the principal barrier to oral rehydration.

There is no specific antiviral treatment for rotavirus infection. Antibiotics have no role given the viral aetiology. Once adequate rehydration is established, resume normal age appropriate feeding early, including continued breastfeeding throughout the illness, rather than imposing prolonged dietary restriction.

Oral rotavirus vaccination is the single most effective preventive intervention. It is given as part of the routine infant immunisation schedule in the majority of national programmes. Specific products and precise schedules vary, generally comprising two or three oral doses.

Doses are given within a defined and relatively narrow age window in early infancy, because a small associated risk of intussusception rises with increasing age at first dose. Vaccination has produced a well documented reduction in the incidence of infection and, critically, in the rate of severe dehydrating disease and associated hospital admission in populations achieving high vaccine coverage.

Strict infection control limits the substantial nosocomial and childcare setting transmission risk of this highly infectious pathogen:

• Hand hygiene
• Appropriate isolation or cohorting of infected patients within healthcare settings
• Environmental cleaning

The virus is non enveloped, environmentally stable and resistant to standard alcohol based hand sanitiser. Soap and water hand hygiene is therefore specifically preferred over alcohol gel alone.