Molecular and demographic analysis of respiratory syncytial virus infection in patients admitted to King Chulalongkorn Memorial Hospital, Thailand, 2007

Objectives: To preliminary preview the molecular character and its possible clinical correlation of RSV subgroups in Thailand. Design: Cross-sectional analytic design. Setting: Admitted acute lower respiratory tract infection patients of King Chulalongkorn Memorial Hospital, Bangkok, during Jun-Dec, 2007 were recruited. Sample: Nasopharyngeal aspirations were collected. Main outcome measures: All samples were analyzed for the presence of RSV glycoprotein G gene by reverse transcription PCR. Molecular character of each subgroup was determined by sequencing. Admission records were also analyzed for clinical correlations. Results: Equal infectivity and severity of both RSV subgroups to the patients was shown. Mixed infection was shown to be as common as each single infection, higher than previously reported. GA2 of subgroup A and BA-IV of subgroup B were the most widespread genotypes and showed their monophyletic origins. From admission records, either type of infection did not show significantly preference in demographic record or clinical severity. Comorbidity, however, was statistically significant that more congenital heart disease was found in negative RSV cases, while more chronic pulmonary disease was in positive cases. Nevertheless, the clinical severity was insignificantly different suggesting that only patients with chronic pulmonary underlying were prone to be infected with RSV. Conclusions: This preliminary RSV study showed prevalence of subgroups, types of infection, and common genotypes in an epidemic, uncorrelated to demography or clinical severity.