PREVALENCE OF ANTIBODIES TO POLIOVIRUSES AND ENTEROVIRUSES EXCRETED BY HEALTHY-CHILDREN IN BOMBAY

A total of 132 healthy children between the ages one month and 12 yr w ere surveyed to determine the prevalence of antibodies to the three po liovirus serotypes. Among infants up to six months of age, 73.2, 85.4 and 56.1 per cent had antibodies to poliovirus types 1, 2 and 3, respe ctively. In children of age groups 7 months to 3 yr and above 3 yr, an tibody prevalence to the three poliovirus serotypes was 90.2, 86.9 and 57.4, and 83.3, 96.7 and 76.7 per cent, respectively. Immunization co verage with three doses of OPV exceeded 85 per cent in children above 7 months of age. Low seroprevalence to type 3 poliovirus in the childr en was conspicuous. Of the 80 faecal samples studied from these childr en, 24 (30%) were positive for virus. Among these isolates, 16 were po liovirus type 1 and three type 2. Intratypic differentiation revealed that 15 of the 16 poliovirus type 1 isolates were of wild origin. Two out of the three poliovirus type 2 isolates were of oral poliovaccine origin. Our data indicate that in spite of good vaccination coverage w ild poliovirus type 1 circulation was endemic in Bombay and; that a la rge number of children were susceptible to poliovirus type 3 infection s.