ABSTRACT
Objective To identify the serotype of 73 non-polio enterovirus (NPEV) strains from acute flaccid paralysis (AFP) cases in Ningxia province,during 1997-2011.Methods Partial sequencing of the VP1 region was amplified by RT-PCR with degenerate primers and sequenced while sequences were compared with the database of GenBank by the BLAST algorithm.Evolution was analyzed by constructing phylogenetic tree using Mega 5.1.Results In this study,a total of 73 NPEVs were analyzed,including 4 strains un-typed,69 strains typed by RT-PCR.A total of 27 serotypes were identified,including 8 serotypes of human enterovirus (HEV)-A,19 serotypes of HEV-B.The HEV-B group (46/69,66.7％) constituted the largest proportion of isolates,followed by HEV-A (23/69,33.3％),but no strains were found that belonged to HEV-C or HEV-D group.In the 69 strains,enterovirus 71 was the most frequently seen isolates,followed by coxsackie-virus A4,16,9 and echovirus 24,6.Conclusion HEV-B was the most predominant (46/69,66.7％) serotype of NPEV in Ningxia during the AFP surveillance,in 1997-2011.
ABSTRACT
<p><b>OBJECTIVE</b>To analyze the genetic characteristics of EV71 strains isolated from HFMD cases in Ningxia Hui Autonomous Region in 2009.</p><p><b>METHODS</b>In 2009, totally 385 specimens from 344 HFMD cases were collected from Ningxia. Enterovirus isolation was performed in RD cell line from all the specimens. EV71 isolates were identified by specific RT-PCR from the positive cultures, and sequences of complete EV71 VP1 encoding region were determined for farther analyses.</p><p><b>RESULTS</b>Totally from 126 EV strains isolated in this study, 58 EV71 strains (46%) were identified. And complete VP1 sequences of 46 EV71 strains were determined, and genetic analyses were performed. It was showed that the nucleotide identity of 46 Ningxia strains with the representatives of A and B genotypes were 81.7%-82.8% and 83.1%-85.2%, and the amino acid identity were 93.9%-95.9% and 96. 2%-97.9% respectively. The nucleotide identity of NingXia EV71 isolates with representatives of subgenotype C1, C2, C3, C4a, C4b, and C5 were 88.3%-90.6% (97.9%-99.6%), 88.3%-90.1% (97.9%-99.3%), 87.8%-89.0% (97.6%-98.9%), 94.2%-98.9% (97.9%-100%), 91.8%-94.1% (98.6%-99.6%), and 86.7%-89.1% (97.9%-98.9%). Phylogenetic tree analysis revealed that 46 stains were clustered with reference stains of subgenotype C4 and the Ningxia EV71 isolates were belonged to subgenotype C4a.</p><p><b>CONCLUSION</b>EV71 of subgenotype C4a had spread widely in Ningxia in 2009, which was absolutely predominant type in Ningxia in 2009 and also as the predominant type in China mainland since 2005.</p>