Ecology of enteroviruses in tropics. I. Circulation of enteroviruses in healthy infants in tropical urban area.

A continuing surveillance on enterovirus infection in healthy infants was conducted from October 1971 through February 1973 in urban areas in Ghana, West Africa. About 40 infants were visited in every two months for collection of faecal specimens and examined for infection. Enteroviruses were recovered in tissue culture. The overall isolation rate of enteroviruses was approximately 44%, and there was no seasonal difference between rainy and dry seasons. The rate of virus isolation in urban areas was significantly higher than in rural areas. Within the urban areas, however, no difference in the rate of virus isolation was detected between densely populated and sparsely populated areas. The results of virus identification revealed that all three types of Poliovirus, many types of Echovirus and a few Coxsackieviruses were isolated during the course of the study. It was observed that improvement of sanitary facilities decreased the frequency of virus infection among infants, but the condition of water supply did not influence the virus infection rate. Neither the age of infants nor the size of siblings showed any relation to the virus isolation rate. It was suggested from the results that many types of enteroviruses have been circulation continuously in the tropical urban community throughout the year.