Epidemic pattern and molecular variation of respiratory syncytial virus strains isolated in Shenzhen from year 2012 to 2013
Objective To study the epidemic pattern and molecular variation of respiratory syncy-tial virus （ RSV） strains isolated in Shenzhen from year 2012 to 2013.Methods The clinical samples iso-lated from patients with influenza-like illness were analyzed by fluorescent RT-PCR to screen RSV positive strains.The C-terminal variable regions of genes encoding G proteins were amplified by nested RT-PCR. Molecular variation was analyzed by using Clustal W and MEGA softwares.Results RSV strains were wide-ly prevalent in Shenzhen from 2012 to 2013.Two epidemic peaks usually occurred in spring and summer/au-tumn of each year.The RSV isolates were subtyped into group A belonging to genotype NA1 and group B be-longing to genotype BAⅨ.Most of the mutations scattered at the C-terminal region of G protein.A few mu-tations caused the disappearance of certain glycosylation sites.A novel recombinant virus strain containing 24 inserted amino acids was identified in 2013, which was likely to be introduced into our country from abroad. Conclusion RSV strains were widely and continuously prevalent in Shenzhen, characterized by constant evolution and variation. 
 
Key words: 
Respiratory syncytial virus;  Epidemic pattern;  Molecular variation