Viral aetiology and epidemiology of acute respiratory infections in hospitalized Saudi children.

1429 male and female Saudi children under age 5 years who were admitted to King Khalid University Hospital Riyadh between April 1993 and March 1996 with complaints suggestive of acute respiratory tract infections (ARI) were investigated to determine with which virus they were infected. Viruses could be detected in 37% of cases with respiratory syncytial virus (RSV) being the most commonly detected at 79%. The following viruses were also detected: parainfluenza type 3 8%; influenza A 6%; influenza B 3%; and adenoviruses 2%. With the exception of parainfluenza type 3 the viruses were at peak activity during October-February. Parainfluenza type 3 could be detected year round but epidemics can occur during June-August the hottest months of the year. 58% of the children presented with bronchiolitis and 26% with bronchopneumonia. A significant association was identified between bronchiolitis and being aged 0-6 months. RSV caused 88% of bronchiolitis cases.