The fluctuating pattern of various genome types of respiratory syncytial virus in Copenhagen and some other locations in Denmark

A semi-nested RT-PCR method based on a region of the F and G glycoprotein g enes was established, allowing the simultaneous detection and differentiati on of group A and group B isolates of respiratory syncytial virus (RSV). Th e PCR products were subjected to digestion with restriction endonucleases t o further differentiate the isolates. Using, in addition, previously report ed studies the prevalence of various genome types in the Copenhagen region over a period of 6 years was established. Furthermore, the prevalence of ge nome types was determined in a distant region in Denmark during the winters of 1996/97 and 1997/98, and in yet another distant region during the winte r of 1997/98. It was shown that the different regions in Denmark to a large extent share the same pool of genome types of RSV. Yet, while the fluctuat ing patterns of the two groups and various genome types were almost identic al at different hospitals in the Copenhagen region, they varied between the different regions. This suggests that epidemics in local communities prima rily rely on region-specific herd immunity parameters and emerge from strai ns endemically circulating in these local communities. Group B strains in C openhagen showed an overall predominance, being predominant in three of the six epidemic seasons studied, and of almost equal predominance in one seas on.