Hospitals, paediatricians and general medical practitioners that are willing to participate in the study over several years have been identified in order to allow valid comparisons to be made between each rotavirus season and within each member country. The proportion of samples collected from hospitalised patients and patients in the community as well as the denominator of children less than <5 years of age in each catchment area will be provided.

Faecal samples submitted for the routine laboratory investigation of infantile gastroenteritis and positive for group A rotavirus antigen will be collected for genotyping. Although rotavirus gastroenteritis is predominantly seasonal, every effort should be made to collect samples throughout the year. An increase in rotaviruses infections outside of the normal seasonal pattern may indicate the emergence of a new strain into an immunologically naive population. Also, rural populations and urban populations should be identified in each country in order to allow for the detection of zoonotic rotavirus infections and reassortant strains resulting from dual infection with animal and human rotaviruses

Population Size:

Approximately 1% of a countries population will experience a symptomatic rotavirus infection each year. The overwhelming majority of symptomatic rotavirus infection will be in children <5 years of age. Experience gained in previous studies would indicate that sampling that covered 0.2% of the infected population, will provide comprehensive data on the diversity of co-circulating rotavirus strains. Strains circulating with an incidence of less than 1% can be identified with this sample size. The samples size will be adjusted to 470 in those countries where the calculated sample size was below the number required to detect virus strains circulating with an incidence of 1%.

Epidemiological data:

Epidemiological data including age, sex, geographical location and setting, date of onset and date of sample collection and symptoms (diarrhoea, vomiting, or diarrhoea and vomiting, or other) will be collected.