Etiological And Molecular Epidemiology Study Of HFMD Caused By Other Enteroviruses In Fujian Province

ObjectivesTo explore the pathogenic spectrum and molecular epidemiology characteristics ofHFMD caused by other enteroviruses (non-EV71and non CVA16enteroviruses) inFujian province in recent years, including the serotype distribution characteristics of otherenteroviruses by time, place, people and other aspects, and genetic evolutionarycharacteristic of each serotype of enterovirus.Methods1.The samples was collected from1340HFMD cases caused by other enterovirus inFujian province during2011-2013,and virus isolation was performed.RT-PCR wasperformed with the isolates from HFMD cases,then the products weresequenced,identified and typed.2. Typed isolates were selected for entire VP1coding gene amplification by RT-PCRand sequencing.Results1.375HFMD cases caused by other enterovirus were successfully identified andtyped, involving21serotypes of non-EV71and non CVA16enteroviruses.CVA6andCVA10were predominant serotypes and accounted for48.5%and25.6%, respectively,followed by CVA4(8.3%).In2011, the most frequently presented serotype was CVA10(41.6%), followed by CVA6(29.9%).In2012the most frequently presented serotype wasCVA6(50.2%), followed by CVA10(18.5%) and CVA4(15.1%). In2013, the mostfrequently presented serotype was CVA6(60.2%), followed by CVA10(28.0%).2.The predominant serotypes in different cities，different gender,different age groupsand different types of cases were CVA6and CVA10，in addition to Ningde city,the constituent ratios of CVA4,CVA6and CVA10were quite where the CVA4is a littlehigher than the others.CVA10infection might be independently associated with severeHFMD.3. The Fujian strains shared the nucleotide diversity of16.3%-28.3%with prototypestrains in every serotype,in addition to the Fujian strain of CVA21,with the nucleotidediversity of12.3%.4. Phylogenetic analysis showed that all of Fujian strains were distinct withprototype strains in each serotype, the Fujian strains were distinct with the foreign strainsand homology with domestic strains (such as Shandong, Shenzhen, etc.) in most ofserotypes, such as CVA6, CVA10, andCVA4, etc.5. Phylogenetic analysis showed that the Fujian strains were clustered into multiplebranches in most of serotypes, such as CVA6, CVA10, andCVA4, etc.Conclusion1.The pathogenic spectrum of HFMD did not change significantly in Fujian provinceduring2011-2013,however,which did change greatly from2011,the constituent ratioes ofEV71and CVA16droped,respectively.In contrast,the constituent ratioes ofCVA6,CVA10,CVA4and CVA5increased,respectively.Especially in2013,CVA6andCVA10together with EV71and CVA16were the predominant serotypes of HFMD. Thepredominant serotypes in different cities，different gender,different age groups anddifferent types of cases were CVA6and CVA10.2. The nucleotide diversity analysis indicated that the Fujian strains were distinct withprototype strains in every serotype.Phylogenetic analysis showed that the Fujian strainswere co-circulating and co-evolving with domestic strains in most of serotypes, such asCVA6, CVA10, and CVA4, etc. There were existences of multiple closely relatedtransmission chains in Fujian province in most of serotypes.3. HFMD in Fujian province was concerned with diverse enteroviruses, differentserotypes were co-circulating and mutual alternating at different times, extensivesurveillance and analysis are required.