ABSTRACT
To measure the incidence of acute respiratory infections and burden of respiratory pathogens in children aged two months to five years. Four periurban communities in Karachi were selected for the study. The children, identified with fever and cough during community surveillance at regular intervals, were referred to especially established study clinics. These children were diagnosed to have no pneumonia, pneumonia and 'severe pneumonia' as per IMCI guidelines. To identify the causative organisms, children with pneumonia and severe pneumonia were investigated with oropharyngeal swabs and blood culture. Acute respiratory infection was seen in 5884 children during 1st February 2002 to 31St January 2003. Of these, 1097 children had pneumonia and severe pneumonia, with an incidence 440.3/1000 children per year for Acute Respiratory Infections and 82.1/1 000 children per year for pneumonias. Haemophilus influenzae, Streptococcus pneumoniae and Klebsiella pneumoniae were isolated from 10.9%, 3.7% and 8.5% of oropharyngeal swabs respectively. Extrapolating from the results of this study, the total number of cases of pneumonias in children aged less than five years in Pakistan is estimated to be 213,116 per year due to H. influenzae, and 71,864 per year due to S. pneumoniae. Incidence of acute respiratory infections in children varies in different communities and is a common cause of morbidity