INFLUENZA SURVEILLANCE IN PUNE, INDIA, 1978-90

Continuous surveillance of influenza was carried out in Pune between 1 978 and 1990. Most of the cases were identified during investigation o f 16 outbreaks of influenza in Pune over this period. The majority of cases were children. Ten of the outbreaks occurred during rainy season s. A total of 290 isolates consisting of several antigenic variants of influenza type A (H3N2), type A (H1N1), and type B viruses were isola ted from throat/nasal swabs that were processed in chick embryos and M DCK cell culture and identified using the haemagglutination inhibition test. These variants circulated every year or in alternate years. Nea rly two-thirds of the influenza virus isolates (181 out of 290) were f rom children aged <10 years. Seasonal analysis indicated that the high est number of isolates (174) were collected during the rainy months of July, August and September, with the maximum number (93) in July.