A study of the genetic variability of human respiratory syncytial virus in Croatia, 2006-2008.

Human respiratory syncytial virus (HRSV) is a common etiological agent of acute lower respiratory tract disease in infants. The molecular epidemiology of HRSV in Croatia over four consecutive seasons (from 2006 to 2008) was investigated. A total of 72 HRSV samples were chosen from 696 screened cases in a pediatric clinic in Zagreb. Molecular characterization of HRSV revealed the predominance of HRSV group B viruses in the first two epidemic seasons and HRSV group A viruses in the next two seasons. According to the phylogenetic analysis, NA1 and BA9 were the predominant circulating HRSV genotypes detected during the study. Overall, 82.9% of all HRSV A strains belonged to the NA1 genotype. The HRSV B genotype BA9, detected in two consecutive seasons (2006 and 2007), was the predominant circulating HRSV B genotype, accounting for 80.6% of all HRSV B strains. This study provides data on the circulation pattern of HRSV genotypes in Croatia and their molecular characterization.