2009 evolution for VP4 of enterovirus 71 strains in Shenzhen / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To analyze the genetic evolution for the common causative agent of hand, foot and mouth disease(HFMD) that VP4 of human enterovirus 71 in Shenzhen district.</p><p><b>METHOD</b>491 sttol specimen were collected from, children with hand, foot and mouth diease in Shenzhen Children's Hospital 2009. After cell culture, VP4 gene of eight EV71 strains were amplified by reverse-transcriptase PCR( RT-PCR), phylogenetic analysis of the VP4 gene was constructed by using MEGA 4. 0.</p><p><b>RESULT</b>The VP4 gene of eight EV71 strains encoding 69 amino acids with full length 207 bp. The nucleotide homology of VP4 gene among eight EV71 strains was 94. 2% -98. 1%, compared with VP4 gene of EV71 strains retrieved from Shenzhen 2001 to 2004 and GenBank was 89. 1%-98. 1% and 79.2%-100% respectively. Asian epidemic strain Fuyang had the highest nucleotide homology, representative strain C4 and Shenzhen strain (AY895144) with 94. 2% -98. 1% secondly. Except for the 54th amino acid of VP4 gene of India reported strain and one of the eight EV71 strains, the homology of the rest amino acids between the eight EV71 strains and those in GenBank was 100%. Compared with representative strain C4,there were seventeen differences in nucleotide sequences of VP4 of the eight EV71 strains. All of the different nucleotides were located at the degenerate password sites except one. There was no significant difference in VP4 gene between the severe and the mild cases of strainS. The eight Shenzhen EV71 strains were classified as sub-genotype C4 in the phylogenetic tree.</p><p><b>CONCLUSIONS</b>The epidemic of EV71 in Shenzhen 2009 was sub-genotype C4. VP4 gene of EV71 was very conservative which dose not belong to the variation section. The variation of most of nucleotide was invalid variation. The amino acids encoded by VP4 gene which variation was almost zero.</p>

Genetic evolution of VP1 of enterovirus type 71 in Shenzhen / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>Genetic evolution of VP1 of enterovirus type 71 in Shenzhen were analyzed.</p><p><b>METHODS</b>All samples were tested by RT-PCR using EV71 specific primer. The VP1 of EV71 were amplified and sequenced. A phylogenetic tree was constructed by comparison of the sequences with subgenotype A, B and C using DNAStar, BioEdit and Mega 3.1 software.</p><p><b>RESULTS</b>Among 35 strains, the homogeneity of the VP1 nucleotide sequence was between 92.1%-100%. The homogeneity of the VP1 nucleotide sequence with subgenotype A and B was between 81.4% -91.1%. The VP1 nucleotide sequence of 35 strains of Shenzhen shared between 93% -97.4% identity with cluster C4. The prevalence strains of EV71 were cluster C4b from 1998 to 2004, and gradually moved to C4a since 2003. All of EV71 were C4b from 2006 to 2008. Also, the homogeneity of the VP1 nucleotide sequence with Anhui FY23 EV71 strain were 94.5% -94.7%, 95.7% -95.8%, 96.2%, 95.4% -97.5%, 96.3% -99.2% from 2003 to 2008. It shows that the homogeneity was increased year by year. There was a mutation (A --> C) at No. 66 nucleotide of VP1 of EV71 that two strains were isolated in 2003 and 8 strains in 2008, that caused amino acid mutation (Q --> H) at No. 22 of VP1.</p><p><b>CONCLUSION</b>EV71 C4b was gradually moved to C4a from 1998 to 2008. There was a missense mutation at No. 66 nucleotide of VP1.</p>

Identification and sequence analysis of E gene of Dengue virus type 2 strain isolated from patient serum in Shenzhen / 中华预防医学杂志

<p><b>OBJECTIVE</b>To isolate and identify the pathogen of Dengue fever from Shenzhen city in 2005 - 2006, and to analyze the molecular characteristics of the isolated Dengue virus strain as well as to explore its possible origin.</p><p><b>METHODS</b>IgM and IgG of serum samples taken from 60 suspected Dengue fever patients were detected by ELISA and immunochromatography, and 9 specimens were positive. Nine samples from patients with early stage Dengue fever were used to isolate virus with C6/36 cell line and the positive cell cultures were identified by MGB fluorescent PCR. The type of isolated virus strain was determined by RT-semi-nested-PCR and fluorescent PCR. E gene of isolated virus strain was amplified by RT-PCR and sequenced. Homology and phylogenetic tree of E gene of Shenzhen Dengue virus with the strains isolated from other areas were constructed.</p><p><b>RESULTS</b>Of nine antibody-positive serum samples, one strain of Dengue virus was successfully isolated. The isolated virus strain was confirmed as Dengue virus type 2 and designated as DEN2-SZ0521. The homology of nucleotide sequence and the deduced amino acid sequence of E gene of SZ0521 with standard type 2 Dengue virus NGC strain was 94.2% and 98.2%, but the homology with standard Dengue virus 1, 3, 4 in the same fragment were 59.1%, 57.2%, 58.5% and 68.1%, 66.7%, 63.2%, respectively. The phylogenetic tree indicated that SZ0521 had the greatest similarity with the Malay0412a/Tw strain and they lied in the same branch of the phylogenetic tree. The corresponding homology of nucleotide sequence and amino acid sequence was 99.8% and 100%, respectively. The isolated Dengue virus type 2 belonged to genotype IV with Indonesia-76, Somalia-84 and Sri Lanka-90.</p><p><b>CONCLUSION</b>Dengue virus was isolated from Shenzhen for the first time, and it was classified as type 2. It was confirmed that the type 2 Dengue virus may come from the epidemic area in Malaysia.</p>

Genetype characteristics of enterovirus type 71 in Shenzhen from 2005 to 2008 / 病毒学报

Genetic characteristics of enterovirus type 71 in Shenzhen from 2005 to 2008 were analyzed. All samples were detected by RT-PCR using EV71-specific primers. The VP1s of EV71 strains were amplified and sequenced. A phylogenetic tree was constructed by comparison of the sequences with those of subgenotype A, B and C using DNASTAR, BioEdit and Mega 3.1 softwares. The VP1 nucleotide sequences of 17 strains of Shenzhen shared 95.3%-99.4% identities with cluster C4a, and one strain shared 93.0%-95.6% identities with cluster C4b. The homogeneity of the VP1 nucleotide sequence with subgenotype A and B was 81.8%-86.0%. Among 18 strains, the homogeneity of the VP1 nucleotide sequence was between 92.5%-100%. All EV71 strains circulating in Shenzhen were of subgenotype C4. The predominant strain of EV71 belonged to cluster C4a, also there was cluster C4b.