| circulation patterns of genetically distinct group a and b strains of human respiratory syncytial virus in a community. | human respiratory syncytial virus (hrsv) is classified into two major groups, a and b, each of which contains multiple variants. to characterize the molecular epidemiology of hrsv strains over time, sequencing studies of a variable region of the attachment protein gene from a single community in the united states during 5 successive years were performed. phylogenetic analysis revealed distinct clades (genotypes) that were further classified in subtypes based on > or = 96% nucleotide similarity. ... | 1998 | 9747732 |