The virus

Rotavirus is a double-stranded RNA virus belonging to the family Reoviridae. It is called rotavirus because by electron microscopy the virus particle resembles a wheel (see Fig. 25.1).

Epidemiology

Route of spread

Rotavirus spreads among humans by the faecal–oral and respiratory routes. There are seven different groups (A–G). Group A rotaviruses are the major cause of human infection, but groups B and C also infect humans. Rotavirus infections occur in most animal species, and although they can infect humans, are mostly associated with mild or no human disease, and no onward transmission.

Prevalence

Rotavirus infections are common in childhood and have a high morbidity with associated mortality in poor developing countries. In the UK, by the age of 5 years 90% of children have been infected. Reinfection can occur throughout life, but only the first infection after loss of maternal protection is associated with severe symptoms, and reinfections in older children and adults tend to be mild or asymptomatic. Infection usually occurs between November and March.

Incubation period

The incubation period of rotavirus is 1–2 days.

Infectious period

Patients are most infectious when symptomatic with diarrhoea and vomiting.