ABSTRACT
Wheezing was detected in 251 of the 421 (59.6%) children under 5 years old suffering from acute lower respiratory infections (LRI) treated at the Takhli Hospital, Nakhon Sawan Province from November 1998 to October 2000. Bronchitis and pneumonia accounted for 55.0 per cent and 40.6 per cent of LRI with wheezing. Most of the patients, 162 of 251 (64.5%) cases were children under 2 years old. The wheezing symptom declined significantly in children older than 4 years of age. In this study, LRI with wheezing was found all year round but was more frequent in the rainy season similar to other respiratory infections. As the respiratory syncytial virus (RSV) infections were mainly found during the rainy season (July-October), the association of wheezing and RSV infections in the rainy season was evaluated. RSV causing LRI with wheezing in the rainy season revealed 54.7 per cent and 39.4 per cent in the first and second studied year, respectively. The two-year follow-up of 121 cases of LRI with wheezing showed that 37 cases (30.5%) had repeated episodes of wheezing. In conclusion, LRI with wheezing caused by RSV was commonly found in children under 2 years old. The occurrence was all the year round but predominantly in the rainy season.