Genetic characteristic analysis of the VP1 gene of echovirus 30 isolated from viral meningitis cases in Yunnan province, 2010-2013 / 中华实验和临床病毒学杂志

Objective@#In this study we analyzed the genetic characteristics of echovirus 30 (E-30) VP1 gene sequences from Yunnan province isolated from viral meningitis (VM) cases in 2010-2013.@*Methods@#RT-PCR and VP1 gene sequencing were done for 9 E-30 strains isolated from VM cases in 2010-2013. VP1 gene sequences of E-30 reference strains were downloaded from the GenBank and their nucleotide (nt) and amino acid (aa) diversities were calculated by MEGA 5.1 software, the phylogenetic tree was constructed and the genetic characteristics and molecular epidemiology were analyzed.@*Results@#In 2010-2013, 9 strains of E-30 viruses were detected from 79 VM cases caused by echoviruses, accounting for 11.39%(9/79), the overall positive rate was 1.63%(9/553). Phylogenetic analysis revealed that E-30 strains can be divided into four genotypes (genotype A, B, C and D), and genotype D can be further divided into seven sub-genotypes. Nine Yunnan VM isolates were distributed in D7 sub-genotype, and can be further clustered into 3 branches: 5 strains isolated in 2010 were clustered in branch 1, it is evident that these viruses were responsible for an aseptic meningitis outbreak in Kunming in that year; one 2011 isolate, together with 2013 isolate and one isolate from healthy children in 2010 were clustered in branch 2, these two branches were Yunnan special branches, and two 2011 isolates had the highest homology with 2003 VM outbreaks′ strains isolated from Shandong, Jiangsu, and Zhejiang, showing that these strains may have the same evolutionary sources.@*Conclusions@#Nine Yunnan VM isolates were distributed in D7 sub-genotype, and these strains have different evolutionary sources, showing that at different times E-30 viruses in the same sub-genotypes branch might prevail in different areas.

Isolation and analysis of genetic characteristics of a new strain of enterovirus EV-C99 from a healthy child in Yunnan Province / 中华微生物学和免疫学杂志

Objective To isolate and analyze the genetic characteristics of a new strain of entero-virus EV-C99 from a healthy child in Yunnan Province in 2016. Methods Virus isolation was performed ac-cording to the World Health Organization ( WHO) recommended procedures. Viral RNA was extracted from the supernatant of cell culture. RT-PCR and sequencing analysis of VP1 gene were used for virus identifica-tion. VP1 sequence was edited and stitched by Sequencher 5. 0 software. The edited sequence was BLAST searched in GenBank and the preliminary result indicated that it was an EV-C99 virus. Nucleotide (nt) and amino acid (aa) identities were calculated by MEGA5. 2 software. Serotype of the virus was identified ac-cording to the standard for enterovirus sequence typing. Results The virus could be amplified by 494/496 and 495/497 primer pairs and the edited sequence was about 1 200 bp. Result of the " BLAST" search showed that it was a new strain of enterovirus EV-C99. Comparative analysis with the prototype strain BAN00-10461 (GenBank ID:EF015008) by MEGA5. 2 software showed that the VP1 gene of that virus was 909 bp and the identities between them were 77. 05% in nt sequence and 90. 04% in aa sequence. According to the standard for enterovirus sequence typing,the virus was a new strain of enterovirus EV-C99 belonging to hu-man enterovirus species C (EV-C). Conclusion A new strain of enterovirus EV-C99 was isolated during an investigation of enteroviruses among healthy children in Yunnan Province in 2016. To our knowledge,this is the third report of EV-C99 in China. Phylogenetic analysis reveals that the EV-C99 Yunnan strain,Xinjiang strains and Shandong strains all belong to genotype B,but group into different clusters,indicating that Chinese strains have diverse genetic characteristics.

Surveillance for enteroviruses in healthy children in Yunnan Province from 2014 to 2015 / 中华微生物学和免疫学杂志

Objective To investigate the enterovirus ( EV)-carrying status and the circulating se-rotypes in healthy children from inner and border areas of Yunnan Province in 2014 and 2015 and to analyze the genetic characteristics of echovirus 6 (ECHO6), ECHO25 and ECHO11 strains. Methods Stool sam-ples were collected from children less than 15 years old living in 6 to 7 counties of 3 inner prefectures/cities and 8 to 9 counties of border prefectures/cities. Altogether 921 samples were collected including 453 sam-ples in 2014 (213 samples in inner counties and 240 samples in border counties) and 468 samples in 2015 (195 samples in inner counties and 273 samples in border counties). Viruses were isolated from the stool samples and their serotypes were identified by gene sequencing. Results The numbers of EV strains isola-ted from the samples collected in inner counties and border counties in 2014 were 20 ( isolating rate:9.39%, 20/213) and 16 (isolating rate: 6. 67%, 16/240), respectively. The overall isolating rate for 2014 was 7. 95% (36/453). The predominant species was enterovirus B, accounting for 88. 89% of all iso-lated strains (32/36), followed by enterovirus A species (11. 11%, 4/36). No strains of enterovirus spe-cies C (including poliovirus) and D was detected in 2014. In total, 46 EV strains were isolated in 2015 with an overall isolating rate of 9. 83% (46/468), including 13 strains in inner counties (isolating rate:6. 67%, 13/195) and 33 strains in border counties (isolating rate:12. 09%, 33/273). Most of the strains were enterovirus B species, accounting for 78. 26% (36/46), followed by enterovirus C species (19. 57%, 9/46) and enterovirus A species (2. 17%, 1/46). Altogether 82 EV strains were isolated in 2014 and 2015 with an isolating rate of 8. 90% (82/921), of which 33 strains were isolated in inner counties (8. 09%, 33/408) and 49 strains were isolated in border counties (9. 55%, 49/513). Among the 82 EV strains, 9 strains were polioviruses (0. 98%, 9/921) and all of them were Sabin-like polioviruses. The rest of the strains were non-polio enterovirus (7. 93%, 73/921). Conclusion In 2014, the EV isolating rate in inner counties (9. 39%) was higher than that in border counties (6. 67%). However, the EV isolating rate in border counties (12. 09%) was higher than that in inner counties (6. 67%) in 2015. Enterovirus B was the predominant species in both 2014 and 2015. No wild type polioviruses and enterovirus D species were detec-ted. Polio-free status was maintained well in Yunnan Province.

Identification and genetic characteristics of non-polio enteroviruses isolated from patients with acute flaccid paralysis in 2015, Yunnan province, China / 中华微生物学和免疫学杂志

Objective To investigate the virus-carrying rate of non-polio enteroviruses ( NPEV) in patients with acute flaccid paralysis ( AFP) in Yunnan province of China in 2015 and to analyze the genetic characteristics of enterovirus 71 (EV71) strains. Methods A total of 213 cases under 15 years old with AFP were reported by Center for Disease Control and Prevention ( CDC) of Yunnan Province of China. Virus isolation was conducted for all samples and the serotypes of isolated NPEV strains were identified by VP1 se-quencing. The isolation rates of NPEV in the past consecutive 5 years were analyzed by SPSS22. 0 software. Phylogenetic trees of NPEV and EV71 strains were constructed by MEGA6. 06 software based on neighbor-joining algorithm and Kimura 2-parameter substitution model and the reliability of the phylogenetic trees was determined by bootstrap analysis with 100 pseudo replicate datasets. Results Altogether, 23 NPEV strains were isolated from 213 AFP cases. Among the 23 strains, 7 strains belonged to EV-A group (2 serotypes, 6 strains of which were EV71 ) , 14 strains belonged to EV-B group ( 8 serotypes ) and the other 2 strains belonged to EV-C group. No NPEV strains of EV-D group were identified. Statistical analysis showed that no significant differences in the isolation rates were observed in the past 5 years ( P=0. 101 ) . Conclusion The isolation rate of NPEV in patients with AFP in Yunnan province in 2015 was similar to that of the previ-ous years. The EV71 strains of C4 subgenotype were the predominant strains circulating in Yunnan province.

Evaluation on the efficacy of prevention programs and relevant factors targeting mother-to-infant transmission on hepatitis B virus in Yunnan province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the efficacy of prevention programs and relevant factors targeting mother-to-infant transmission of HBV in Yunnan province.</p><p><b>METHODS</b>In Yunnan province, we selected HBsAg positive pregnant women that delivered in hospital from January 1st through June 30th, 2011. Newborns of these pregnant women were under PMTCT (prevention of mother to child treatment) program and followed. Every infant was drawn 2 ml venous blood and questionnaire survey was carried out when the baby was 7-12 month-old and completed the vaccination processes. Serum samples of them were then collected and detected on the 5 serological indicators of HBV.</p><p><b>RESULTS</b>were analyzed statistically.</p><p><b>RESULTS</b>There were 2 765 infants in the study program. The success rate of PMTCT was 95.88% . Rates of coverage on both timely-birth dose and 3 doses of HepB were 97.03% and 92.30% respectively. The overall vaccinated rate and timely-birth vaccinated rate on hepatitis B immunoglobulin (HBIG) were 68.97% and 94.49% respectively. The success rate of PMTCT was 97.16% after administration of passive-active immune-prophylaxis (HepB and HBIG), compared to the rate as 93.01% when vaccinated with HepB only. Significant differences were seen in the successful rates of PMTCT between combined and non-combined immunization. Either the combined or non-combined immunization, there were significant differences seen in the success rates of PMTCT regardless the positivity status of HBsAg or HBeAg, among the infected mothers.</p><p><b>CONCLUSION</b>The efficacy of passive-active immune-prophylaxis program seemed to be better than the one without combined immunization. It was vitally important for the infants whose mothers' HBsAg and HBeAg status were positive, to receive regular and timely combined immunization. In order to promote the PMTCT in Yunnan province, vaccinated rate on HBIG should be further improved.</p>

Genetic characteristic analysis of echovirus 11 / 中华微生物学和免疫学杂志

ObjectiveTo study echovirus 11 ( ECHO11 ) sequences genetic variability of the VP1 gene of 82 isolates from 15 countries and 2 provinces in China.MethodsThe VP1 sequences of 82 strains of echovirus 11 were downloaded from the GenBank,and their nucleotide and amino acid diversity were calculated and phylogenetic tree was constructed using Mega software.Results82 echovirus 11 strains were divided into 4 genotypes( A-D),Genotype A is further divided into 7 subgenotyps and genotype D into 7 subgenotyps.The prototype strain Gregory is the sole member of genotype B.Genotype C is divided into 3 genotypes.The sequence diversity between echovirus 11 strains is 21.7%-24.1% (AA diversity:6.0%-12.1% ).ConclusionOur results show that most genotypes contain isolates that have circulated over a wide geographical(several countries from different continents) and temporal range.Several genotypes were also shown to co-circulate in a region during the same period of time,showing that the epidemic of echovirus 11 has typical time and geographical characters.