Abstract

STUDY OBJECTIVES--To assess the amount of poliomyelitis and its epidemiological features including risk factors. DESIGN--This was a retrospective study of cases of paralytic poliomyelitis among children 0-6 years of age. SETTING--Pondicherry, India, 1983-89. SUBJECTS--A total of 47,960 children aged less than 6 years. MEASUREMENTS AND MAIN RESULTS--In 1989, 469 field workers undertook a door to door survey of children 0-6 years old to identify those with limb paralysis. This was followed by clinical examination to establish the cause, supplemented by case notes held by the Child Development Services. Altogether 203 cases of limb paralysis were identified, 188 of which were judged a result of paralytic poliomyelitis. The prevalence of poliomyelitis in 1989 was 3.9/1000 among children below 6 years of age. There was a male preponderance with a male:female ratio of 1.4:1. The prevalence was least in infants (1/1000) and highest in children aged 2 to 3 years (6.4/1000). The age at onset was less than 12 months in 42% of cases and less than 3 years in 98%. The median age at onset was 13.4 months. Time series analysis showed a high occurrence of cases from May to September between 1983 and 1989. The legs were affected in 97%. About 41% of children had received three doses of oral polio vaccine. There was a history of intramuscular injection, possibly provoking a paralytic attack, in 54% of cases. CONCLUSION--This retrospective community study involving the staff of the Integrated Child Development Services provided valid data about poliomyelitis with little additional cost and minimum training. Because the study covered a whole population of children under 6 years, rather than a sample, the data will help in monitoring and surveillance of poliomyelitis and also in planning strategies for effective control.