Epidemiology of rotavirus in a periurban Gambian community.

Short, well demarcated epidemics of rotavirus diarrhoea were observed during two consecutive cool, dry seasons in The Gambia. This seasonal pattern has now been documented for 4 consecutive years. During the 1985/86 epidemic, transmission was intense, with a clinical attack rate for infants of 36%. During this outbreak it was estimated that asymptomatic virus-shedding was two-thirds as common as symptomatic infection. Rotavirus diarrhoea was more severe than diarrhoea due to all other causes and clinical rotavirus infection was associated with weight loss in the post-infection period. Non-epidemic periods were characterized by very occasional mild cases and asymptomatic virus-shedding in neonates. There was a change in RNA electropherotypes from a predominantly long pattern in 1983/84 and 1984/85 to short patterns in 1985/86.