ABSTRACT
Objective To study the genomic genotypes and variation of human enterovirus 71(EV71)infected infants in Guangzhou city,in 2008 and 2010.Methods Primers were designed on the basis of the genomic sequence of EV71 SHZH03 strain(AY465356)in the GenBank,and EV71genome amplified by RT-PCR.PCR-products were directly sequenced and the genomic nucleotide sequences were analyzed with the programs of Clustal W/X,DNASTAR and MEGA 4.1.Results 9strains of EV71 genome appeared to be 7405 bp in length.The genomic sequences of EV71Guangzhou strains were compared with those of EV71 in GenBank,which revealed that the homology with EV71 genotype C4a Fuyang strains ranged between 98%-99%.Homology with genotype C4b were 92%-94%,with genotypes C1,C2,C3 as 82%-83%,with genotypes B3,B4,B5 as 81%-83%and the homology with genotype A was 80%.When compared the VP1 genes of EV71 Guangzhou strains with genotypes A,B,C virus,we revealed that the highest homology was also with genotype C4a.When compared the VP1 amino acid sequences of EV71 Guangzhou strains with genotype A,B,C virus by Clustal W program,the results revealed that the amino acid residue Q at position 22 in VP1gene was transformed to H,while 213(S→T)and 1764(V→(Ⅰ))mutations in polyprotein were discovered.Conclusion Data from the sequences and phylogenetics analysis on those Guangzhou strains in 2008 and 2010 revealed that those isolates belong to genotype C4a,with the homology with Fuyang strains as 98%-99%.Mutation of amino acid residue H at position 22 in VP1 gene was discovered and the neutralizing antibody of EV71 might have been conversed by this residue.213(S→T)and 1764(V→Ⅰ)mutations in polyprotein were also discovered.
ABSTRACT
<p><b>OBJECTIVE</b>To understand the etiology of hand, foot and mouth disease (HFMD) in Guangzhou area in 2008.</p><p><b>METHOD</b>Totally 1023 clinical specimens were collected from pediatric patients suspected of HFMD in 2008. TaqMan real-time RT-PCR were used for detection of enterovirus 71 (EV71), Coxsackievirus A16 (CA16) and other enteroviruses. The specimens which were enterovirus positive by RT-PCR method with universal primer but EV71 and CA16 negative, were amplified and sequenced for 5'untranslated region.</p><p><b>RESULT</b>Enterovirus was identified from 434 of 1023 samples and detection rate of enterovirus was 42.42%; of the 434 samples, 276 were positive for EV71 (63.6%), 126 for CA16 (29%), 4 samples for enterovirus 84, 3 for Echovirus 11, 2 for Echovirus 9, 3 for Coxsackievirus B3, 4 for Coxsackievirus A10, 3 for Coxsackievirus A6, 6 for Coxsackievirus A12 or A5, and for 7 samples typing was difficult.</p><p><b>CONCLUSION</b>The major causative agents of HFMD in Guangzhou were EV71 and CA16 in 2008, and EV84, CA10, CA12, CA6, COSB3, ECHV11, ECHV9 were also the pathogens for smaller proportions of patients.</p>