Molecular Epidemiological Analysis Of Hand-foot-mouth Diseases And Its Clinical Correlation

OBJECTIVES: To isolate and identify etiologic agents associated with hand-foot-mouth diseases presenting with specific clinical manifestation during its outbreak in Shanghai,2012-2013.Additionally,molecular epidemiology,phylogenetic analysis,recombination analysis,and clinical study were also performed.METHODS: From January 2012 to September 2013,clinical specimens from 626 hand-foot-mouth disease(HFMD)cases were detected and identified by reverse transcription-polymerase chain reaction(RT-PCR)methods.The demographic and clinical data were analyzed for coxsackievirus A6(CVA6)-infected cases.Whole-genome sequencing and recombination analysis were conducted for several clinical CVA6 isolates.The identification of the novel recombinant CVA6 isolates from all CVA6 isolates was also performed.Molecular determination of the recombinant CVA6 virus and phylogenetic analyses were performed.Viral replication kinetics and cytopathic effects were evaluated for the recombinant CVA6 and non-recombinant CVA6 virus.RESULTS: A recombinant CVA6 monophyletic lineage was found during HFMDs outbreak in Shanghai,China since late 2012,and accounted for 21.9%(64/292)of CVA6 outbreak strains.Molecular analyses showed the 2C gene of the novel CVA6 virus was derived from coxsackievirus A4(CVA4)virus.The putative recombination breakpoint was found to locate at 4041 nt.Clinical observation showed that this recombinant CVA6 virus led to a more generalized rash than did the non-recombinant CVA6 virus.CONCLUSIONS: A novel inter-typic recombinant CVA6 lineage was associated with considerable proportion of HFMD cases from late 2012 to 2013 in Shanghai,China.The novel recombinant CVA6 virus can cause more widespread skin rash.