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Objective:To study the genetic characteristics and genetic evolution of echovirus 30 (ECHO30) isolates in Yunnan Province, China.Methods:Virus isolation was performed on nucleic acid-positive samples for hand, foot, and mouth disease pathogen surveillance in Yunnan Province, and VP1 gene sequencing was performed. The sequences of eight ECHO30 isolates from Yunnan Province and the gene sequences of the VP1 region of the ECHO30 reference strain downloaded from GenBank were compared and analyzed using MEGA 5.0 software, and then a phylogenetic tree was constructed to measure the homology of nucleotides and amino acids between the isolates.Results:The ECHO30 virus was distributed in Wenshan, Qujing, Chuxiong, and Kunming in Yunnan Province. The ECHO30 virus was relatively common in Wenshan. ECHO30 isolates belonged to the H2 subtype of the H genotype, which was close to the local reference strain LC120939 in Yunnan Province. On the VP1 gene at site 5, the amino acid change ratio was more active, the amino acids were diverse, and mutations also occurred at sites 54, 156, 258, and so on. Nucleotide and amino acid homology were 84.0% - 100.0% and 98.4% - 100.0%, respectively.Conclusions:ECHO30 isolates from Yunnan Province have certain geographical characteristics and belong to H2 of the H genotype. The nucleotide differences in virus sequences among subtypes are small and have a close genetic relationship.
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Objective:To investigate the predominant types of enteroviruses and the characteristics of the VP1 gene of coxsackievirus A4 (CVA4) causing hand, foot and mouth disease (HFMD) in Yunnan Province from 2018 to 2020.Methods:Throat swab and stool samples were collected from HFMD cases and tested by real-time quantitative PCR for nucleic acid detection. The samples positive for enterovirus nucleic acids were used for viral isolation and sent to the National Center for Disease Control and Prevention. The VP1 gene of the isolated strains was sequenced and analyzed.Results:From 2018 to 2020, a total of 21 757 HFMD samples were collected, 16 457 (75.64%) of which were positive for enteroviruses. Altogether 533 strains were isolated from 4 114 positive samples that were selected for viral isolation, including 89 strains of enterovirus 71 (EVA71, 16.70%), 180 strains of coxsackievirus A16 (CVA16, 33.77%), 76 strains of CVA10 (14.26%), 118 strains of CVA6 (22.14%), 26 strains of CVA4 (4.88%) and 44 strains of other types (8.26%). HFMD occurred mainly in children under five years old with higher incidence in males than in females (1.35∶1). The incidence of HFMD reached the peak in the second and third quarters. In Yunnan Province, CVA4 mainly circulated in Qujing and Kunming, and was sporadically detected in Wenshan and Honghe. The VP1 gene was 915 bp in length. Twenty-six CVA4 strains belonged to C2 subtype, which were genetically far from the prototype strain AY421762-HighPoint. Mutations in the VP1 gene were found at multiple sites including 18, 23, 34, 102, 148, 164, 200, 262, 174, 275, 285 and 303. These strains showed 80.4%-99.0% homology in nucleotide sequence and 95.6%-99.0% in amino acid sequence. Nucleotide mutations were mostly synonymous mutations.Conclusions:CVA16, CVA6, EVA71 and CVA10 were the predominant enteroviruses causing HFMD in Yunnan Province from 2018 to 2020. The prevalence of CVA4 was also worthy of attention. CVA4 isolates in Yunnan Province belonged to C2 subtype, mainly circulating in the east and southeast of Yunnan Province and gradually becoming a cocirculating predominant strain. Long-term dynamic monitoring would be of great public health significance for improving the sensitivity of HFMD early warning.
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Objective To understand the dynamic changes of the pathogen spectrum of viral diarrhea in Southwest China, and to provide a scientific basis for formulating prevention and control measures. Methods A total of 2 262 fecal samples of diarrhea cases were collected from the diarrhea monitoring sites in Yunnan, Sichuan, and Chongqing from January 2017 to December 2019. The detection of rotavirus, norovirus, adenovirus, astrovirus, and sapovirus was performed by real-time PCR, and their epidemiological data were collected. Results The ratio of male to female patients was 1.30:1. The majority of patients were 3 years old and younger, accounting for 52.21%% of all cases. Children living at home accounted for 49.38% of all cases. The detection rate of rotavirus was 10.70%, followed by norovirus at 10.43% and adenovirus at 4.60%. The detection rate of rotavirus was the highest in Yunnan and Chongqing, which were 20.18% and 16.96%, respectively, while the detection rate of norovirus was the highest in Sichuan, which was 13.54%. Conclusion Rotavirus was still the main diarrheal pathogen in Southwest China. High incidence of diarrhea occurred in autumn and winter, with children living at home being the main patients. Measures should be taken to prevent outbreaks caused by norovirus and adenovirus.
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Objective To investigate the mutation of hemagglutinin gene and amino acid variation of influenza B.Methods Influenza B virus was isolated from throat swab samples in sentinel surveillance of Yunnan province from 2009 to 2014.HA1 gene sequence analysis was applied to determine 12 randomly-selected strains of influenza B virus.The results were analyzed,MEGA software was used to do homology comparison and HA gene phylogenetic tree was established.Results Differences on the serotype and genotype identification of influenza strains were found and it might be caused by inadequate gene mutation accumulation.Amino acid variations were found in 3 important regions of antigenic determinants in HA1 protein:ring 120,ring 150 and ring 160.The amino acid variation of position 131 in ring 120 was N131K,and in position 137 was N137H.Two strains had P187S mutation in position 187.Conclusion There are some important variations in the hemagglutinin gene of influenza B strains in Yunnan Province,with some variations being the same as vaccine strains and some being not.
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To analyze influenza pathogen spectrum in Yunnan province during 2009-2014 years, and analyze HA and NA genes of influenza A H1N1. Analysis was made on the monitoring date of influenza cases in Yunnan province in recent 6 years, 23 strains of influenza virus of HA and NA gene was sequenced and analyzed by MEGA 5 software to construct phylogenetic tree. 4 times of influenza AH1N1 epidemic peak were monitored from 2009-2014 years in Yunnan Province, as the nucleic acid detection results of influenza A H1N1 accounted for 28.8% of the total. The sequencing result showed that HA and NA gene were divided into 3 groups, one was detected with H275Y mutation strains. Influenza A H1N1 is one of the important subtypes in Yunnan province and their genes have divided into three branches during the period of 2009-2014 years, the vast majority of influenza a H1N1 are still sensitive to neuraminidase inhibitors.
Subject(s)
Humans , China , Epidemiology , Hemagglutinin Glycoproteins, Influenza Virus , Genetics , Metabolism , Influenza A Virus, H1N1 Subtype , Classification , Genetics , Influenza, Human , Epidemiology , Virology , Molecular Sequence Data , Mutation , Neuraminidase , Genetics , Metabolism , Phylogeny , Viral Proteins , Genetics , MetabolismABSTRACT
Objective To understand the viral etiology of acute respiratory infection in Kunming area. Methods We collected the nasopharyngeal swab of patients with acute respiratory tract infection,and used multiple reverse transcription-polymerase chain reaction (RT-PCR) method to detect 15 kinds of respiratory viral pathogens. Results Among the 600 samples,144 strains of viruses were detected, the positive rate was 24%,among which the highest positive rate was RSV (49/600,8.2%),followed by PIV (32/600,5.3%) HRV (27/600,4.5%) and IFV27 (27/600,4.5%) . The respiratory virus infection situation was different in every age group, groups of the highest virus positive rate was ≤1 age group (72/216, 33.3%);The respiratory virus infection situation in different seasons was different, the virus positive rate of the first quarter was the highest (85/144, 59%) . Conclusion RSV was the main virus pathogen of acute respiratory tract infections in Kunming area in 2011 years, the detection rate in sick children was the highest among all patients;the detection rate in the first quarter was higher than other quarters.