An epidemiological study of rotavirus diarrhoea in a cohort of Nigerian infants: II. Incidence of diarrhoea in the first two years of life.

In a community-based prospective study of diarrhoeal diseases carried out in Ibadan, 131 infants were selected at birth. The maximum possible length of follow-up ranged from 16 to 24 months. Weekly surveillance for diarrhoea was carried out at home by Primary Health Care workers. Each child was also required to attend a monthly clinic. Of the 131 babies, 95 (73%) completed at least one year of follow-up. All of these had at least one episode of diarrhoea within the first year of life. The incidence rate of diarrhoea in the first year of life was 3.2 cases/child/year. The mean duration of diarrhoea days in the first year of life was 16 per child per year (range 3-34 days). The peak incidence of diarrhoea and the greatest number of diarrhoea days were in the age interval 6-9 months. The mean duration of diarrhoea was five days per episode. Faecal samples for 280 diarrhoea episodes during the first year of life were examined for rotavirus using the ELISA technique: 22 (7.7%) were found to be positive. The mean duration of rotavirus diarrhoea episodes was eight days.