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Objective The long-term epidemiological and etiological characteristics of hand, foot and mouth disease (HFMD) in Huai’an, Jiangsu were analyzed to provide scientific evidence for the prevention of HFMD. Methods The data of HFMD reports, etiological diagnosis and in Huai’an from 2009 to 2022 were described and analyzed. Results A total of 78 535 cases were reported from 2009 to 2022 , with 14-year average annual incidence rate of 114.71/100 000. Before 2020, the incidence rate of HFMD in Huai’an showed the epidemic intensity increased every other year on the whole, and the average annual incidence rate during the COVID-19 pandemic (2020-2022) (55.69/100 000) was significantly lower than that in previous years (2009-2019) (129.95/100 000). The joinpoint regression analysis showed that the best fitting model from 2009 to 2022 had no joinpoints, APC=AAPC=-1.24%. The overall trend showed a monotonously decreasing trend, but the trend was not statistically significant. The male-to-female distribution ratio was 1.53:1, and the age distribution was mainly under 5 years old, especially in scattered children. The epidemic season was from April to July. The results of etiological surveillance showed that the co-epidemic of Coxsackievirus A16 (CV-A16) and Enterovirus A71 (EV-A71) during the early stages had changed to the co-epidemic of CV-A16 and CV-A6 in the current period. Conclusion The burden of HFMD in Huai’an was large, and the epidemic intensity increased every other year was affected by the COVID-19 pandemic. The epidemiological features after the COVID-19 pandemic should be further monitored.
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Objective:To retrospectively analyze the molecular epidemiological features and genetic recombination of coxsackievirus A4 (CVA4) strains isolated in Jiangsu from 2015 to 2022.Methods:Throat or anal swab samples were collected from patients with herpangina or hand, foot and mouth disease (HFMD). Real-time PCR was used to detect CVA4. A comprehensive and systematic phylogenetic analysis was conducted based on 72 whole genomes and 99 VP1 sequences of CVA4 strains. Several bioinformatics software including DNAStar, MEGA7.0 and Similarity plots3.5.1 was used for analysis of homology, genetic recombination and amino acid variation sites.Results:Four genotypes (A, B, C and D) and five sub-genotypes (C1-C5) of CVA4 were identified based on the VP1 nucleotide sequences. C2 was the predominant sub-genotype causing HFMD. The Jiangsu strains showed high homology with the CVA4 prototype in the P1 region, and higher identity with other strains of enterovirus group A (EV-A) in the P2 and P3 regions. Genetic recombination analysis revealed that the Jiangsu strains had three genetic recombination patterns with other EV-A epidemic strains in the P2, P3 and 3′-UTR regions. These recombination patterns took place during the sustained and widespread circulation of CVA4 in people and increased the transmissibility of CVA4.Conclusions:This study analyzes the phylogenetic and molecular features of 28 whole genomes of Jiangsu CVA4 strains, which helps to better understand the genomic diversity of CVA4. By analyzing the genetic recombination and amino acid mutations in the VP1 region, this study elucidates the evolution and transmission of CVA4, which is conducive to the control and prevention of CVA4 infection.
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@#Objective To analyze the whole genome sequence and genetic characteristics of the Yunnan isolate of Coxsackievirus A8(CVA8),A8-1/YN/CHN/2019,in order to understand the prevalence and variation of CVA8.Methods The primers for CVA8 were designed,the viral RNA was extracted,the VP1 sequence was amplified by RT-PCR and sequenced,and the whole genome was spliced using BioEdit 7.2.3. MEGA 7.0 software was used for the phylogenetic analysis,and Simplot 3.5.1 and RDP4 software were used for the recombination analysis.Results Strain A8-1/YN/CHN/2019 was7 396 nt long and encoded 2 188 amino acids. The homologies of nucleotide and amino acid sequences between VP1 and CVA8 prototype strain AF081299/Donovan/USA/1998 were 81. 04% and 95. 24%,respectively. Strain A8-1/YN/CHN/2019 belonged to genotype E,while the other Chinese isolates were located in genotypes D and E. Recombination analysis revealed that strain A8-1/YN/CHN/2019 recombined on segments P2 and P3 of the non-structural coding region.Conclusion Strain A8-1/YN/CHN/2019 is of genotype E and has recombination events in the non-structural regions of the P2 and P3 segments.
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@#Objective To analyze the genetic characteristics of the entire VP1 gene of Coxsackievirus A16(CVA16) strains isolated from the feces of patients with hand,foot and mouth disease(HFMD) in Yunnan Province in 2019.Methods The virus was isolated from human embryonic lung diploid fibroblast(KMB-17) cells and African green monkey kidney(Vero)cells,and the primers for the complete VP1 gene sequence of CVA16 were designed.The target fragment was amplified by RT-PCR and sequenced;the complete VP1 sequence was analyzed by softwares such as MEGA 7.0 and Geneious 9.0.2.Results A total of 26 CVA16 strains were isolated,including eight KMB-17 isolates and 18 Vero isolates.Twenty CVA16isolates were randomly selected for analysis,and three isolates were found to have Bla and 17 B1b genotypes;the nucleotide and amino acid homology of 17 CVA16 B1b isolates were 93.8%—100% and 98.3%—100%,and the nucleotide and amino acid homology with other domestic isolates was 91.1 %—99.2% and 97.3%—99.0%,respectively;the nucleotide and amino acid homology of the three Bla isolates was 98.0%—98.1% and 99.3%,and those with other domestic Bla isolates was 88.7%—98.1% and 98.3%—99.7%,respectively;17 B1b isolates and other three Bla isolates showed the nucleotide and amino acid homology of 87.4%—88.4% and 97.3%—98.7%.Conclusion The CVA16 prevalent in Kunming in 2019 belonged to Bla and B1b genotypes,with B1b as the main strain,and all of them were prevalent strains in the mainland of China.
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Coxsackievirus group B (CVB) belongs to human enterovirus and contains six serotypes. CVB infection in humans usually causes mild symptoms, but can lead to myocarditis, pancreatitis, hand, foot and mouth disease and central nervous system diseases, which is extremely harmful to infants and young children. There are outbreaks of CVB in many places at home and abroad. The epidemic patterns of different serotypes are distinct and complicated. Currently, there are no effective drugs or means to treat or prevent CVB infection. Vaccine is expected to be a cost-effective way to address CVB-related public health concerns. Although there is no CVB vaccine on the market, many institutions are conducting preclinical studies of various types of CVB vaccines, including nucleic acid vaccines, viral vector vaccines, recombinant protein vaccines, live-attenuated vaccines and inactivated vaccines. This article reviewed the advances in the research of CVB vaccines.
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Objective To predict and analyze the physicochemical properties, structural characteristics, and antigenic epitopes of viral protein (VP) VP1 of Coxsackievirus A10 (CV-A10) by bioinformatics methods. Methods The physicochemical properties and structural characteristics of CV-A10 VP1 were predicted by ProtParam, SOPMA, SWISS-MODEL, PDBsum, and ProSA-web. The antigenic epitopes of CV-A10 VP1 were predicted and analyzed by DNAstar, ABCpred, Bepipred 2.0, ElliPro, DiscoTope-2.0, NetMHCpan-4.1, NetMHCIIpan-4.0, Consurf, VaxiJen v.2.0, AllerTOP v.2.0, ToxinPred2, and IEDB immunogenicity. Results Bioinformatics analysis showed that CV-A10 VP1 was a basic, unstable, and hydrophilic protein, of which the secondary structure mainly consisted of random coil. The analysis revealed that CV-A10 VP1 had multiple potential B and T cell antigenic epitopes as well as a dominant antigenic epitope based on the potential epitope. Conclusion CV-A10 VP1 has multiple potential sites that induce specific humoral and cellular immunity, providing important support for its experimental identification, molecular epidemiological studies, and vaccine development.
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@#ObjectiveTo analyze the genome-wide characteristics of 17 strains of Coxsackievirus A6(CVA6)that cause hand,foot and mouth disease(HFMD)and herpangina(HA)in Yunnan Province in 2018,and understand the genetic differences between different pathogenic CVA6.MethodsA total of 1 909 stool samples clinically diagnosed as HFMD and HA in Kunming Children′s Hospital in 2018 were randomly selected for detection using enterovirus group A universal primers and screening of CVA6 positive samples. The CVA6 whole genome sequence was amplified with CVA6 whole genome primers,spliced by BioEdit splicting software,and analyzed for the whole genome characteristics by BioEdit,MEGA 7.0,Simplot,Heml 1.0 and Phyre2softwares.ResultsA total of 929 CVA6 positive samples were screened,and 17CVA6 complete gene sequences were obtained(9 of which were clinically diagnosed as HFMD and 8 were clinically diagnosed as HA). All 17 CVA6 strains were in type IV clade on the whole phylogenetic tree. No significant recombination occurred in HA and HFMD representative strains,while mutations occurred in non-structural protein 3D region. HFMD and HA representative strains showed differences in VP1 loci S597T,Q705L and Q663L. Online predictive analysis showed that the secondary structure of VP1 was consistent with that of CVA6 with no change.ConclusionThe 17 CVA6 strains causing HFMD and HA had high genomic homology,as well as nucleotide and amino acid differences,which may affect the replication and adaptability of CVA6.
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@#Hand-foot-mouth disease(HFMD) is an infectious disease that seriously affects the health of infants and young children and has become a major public health problem worldwide,especially in the Asia-Pacific region.HFMD can be caused by a variety of enteroviruses,the most common being enterovirus 71(EV71) and Coxsackievirus A16(CVA16).In recent years,with the significant increase of HFMD caused by Coxsackievirus A6(CVA6) infection,CVA6 has gradually become the main pathogen of HFMD in many countries and regions around the world.CVA6 is not only susceptible to children,but also infects adults with normal immune function.The paper reviewed the CVA6 related etiology,epidemiology,clinical symptoms,laboratory diagnosis and development of vaccine.
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Enteroviruses are currently divided into groups A to J, among which groups A to D can infect human body. People infected with enterovirus can present invisible infection, which can lead to different clinical symptoms when the immunity is weakened. Among the diseases caused by enteroviruses, hand-foot-mouth disease, herpetic angina, and encephalitis have attracted much attention. Coxsackie virus A21 (CV-A21) belongs to enterovirus C group, which mainly causes acute respiratory tract infection. According to research reports, CV-A21 infection has been found in many countries and regions, and the infection scope is gradually expanding. In the past two years, it has been found that CV-A21 infection has a significant association with the outbreak of acute respiratory tract infection. This indicates that acute respiratory tract infection caused by CV-A21 infection may have potential public health problems. However, there are few studies on the epidemiology and pathogenic mechanism of this virus, and most of the studies are on the mechanism of its oncolytic action on specific malignant tumors. Therefore, in this paper, the structural characteristics, epidemiological characteristics, infection mechanism and oncolytic effects of CV-A21 are reviewed to provide relevant clues for the understanding and exploration of CV-A21.
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@#ObjectiveTo construct self-amplifying RNA(saRNA)vaccine of severe acute respiratory syndrome coronavirus2(SARS-CoV-2)Delta mutant strain(B.1.617.2)based on Coxsackievirus-A5(CV-A5)replicon and evaluate its immunogenicity.MethodsThe recombinant plasmids pDelta-S10,pDelta-S5 and pDelta-S1(10,5 and 1 amino acid residues at the upstream of S-VP1/2A cleavage site of the fusion polyprotein respectively)were constructed by In-fusion cloning of the plasmids containing the full-length genome sequence of CV-A5 and substituting the S protein gene of SARS-CoV-2 Delta mutant for the P1 structural protein gene of CV-A5 with different lengths.Three RNA molecules,Delta-S10,Delta-S5 and Delta-S1,were obtained by in vitro transcription of linearized recombinant plasmids and transfected into HEK-293T cells respectively,which were analyzed for the expression of S protein by Western blot.The RNA molecule with the highest expression of S protein was screened out and detected for the self-amplification in HEK-293T cells by qPCR.BALB/c mice(female,6 ～ 8 weeks old and five for each group)were immunized i.m.with two doses(0.5 and 2.5 μg)of the screened Delta-S packaged with lipid nanoparticles for once on day 1 and day 14 seperately.Blood samples were collected on days 14and 28,detected for serum binding antibody titers by ELISA,and detected for neutralizing antibody titers by micro neutralization method.The spleens were harvested on day 42 and detected for the level of IFNγ secreted by mouse spleen cells by enzyme linked enzyme linked immunospot assay(ELISPOT).ResultsThe recombinant RNA molecule Delta-S10showed the highest expression of S protein and self-amplified in HEK-293T cells,which of both high and low doses induced specific binding antibody against SARS-CoV-2 Delta S1 protein in mice with obvious dose effect and enhanced immune effect;The high dose of Delta-S10 induced neutralizing antibodies and cellular immune responses in mice.ConclusionThe SARS-CoV-2 Delta mutant(B.1.617.2)saRNA vaccine Delta-S10 based on CV-A5 replicon was successfully constructed,which induced humoral and cellular immune responses in mice,laying a foundation of the further study of the construction of SARS-CoV-2 saRNA vaccine by enterovirus replication elements.
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@#ObjectiveTo establish the national reference panel for coxsackievirus A16(CA16)nucleic acid detection kit and related quality standard.MethodsThe CA16 positive and negative samples were collected and screened,and then were filled and lyophilized to establish the national reference panel for CA16 nucleic acid detection kit. According to the cooperative calibration results of various reagent manufacturers,the quality standard of reference panel was determined.Meanwhile,the homogeneity and stability of the national reference panel were well studied.ResultsThe national reference panel of CA16 nucleic acid detection kit consisted of 9 positive samples,8 negative samples,1 limit-detecting sample and1 precision sample. The quality standard was as follows:the coincidence rate of positive samples was no less than 8/9;The coincidence rate of negative samples was 8/8;The minimum detection limit required that the dilution of limit-detecting sample was no less than 1∶103;The precision required that the coefficient of variation(CV)of Ct value of 10 precision samples diluted 100 times was no higher than 5% and the results were all positive. The homogeneity of the reference panel met the requirement,and the stability was not affected by the storage at room temperature(25 ℃)for 24 hours and repeated freezing and thawing three times.ConclusionThe first national reference panel of CA16 nucleic acid detection kit and the related quality standard have been established,which provided a reference for the quality control and evaluation of the related reagents.
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Two new ursane triterpenoids along with twelve known compounds were isolated from 80% ethanol extract of Agastache rugosa (Fisch. et. Mey.) O. Kuntze by using silica gel column, MCI column, ODS column and HPLC. The structures of the new compounds were identified as 2α,3α-dihydroxy-24-nor-urs-4(23),12(13)-dien-28-oic acid (1) and 2α,3α-dihydroxy-24-nor-urs-4(23),12(13),20(30) -trien-28-oic acid (2) by HR-ESI-MS, NMR and ECD spectral data, named agasursacid A and agasursacid B. In addition, compounds 3, 4, 6, 8 showed anti-coxsackievirus B3 (CVB3) activities with a IC50 as 4.77, 1.59, 11.11 and 25.87 μmol·L-1, resepectively.
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Objective:To analyze the whole-genome sequences of coxsackievirus A10 (CVA10) strains isolated in Jiangsu Province from 2015 to 2022 and their molecular epidemiological characteristics.Methods:Forty-five CVA10 isolates circulating in Jiangsu Province during 2015 to 2022 were selected for whole-genome sequencing. Phylogenetic trees were constructed based on the whole genome, VP1, P1, P2 and P3 sequences of CVA10 strains. Bioinformatics software, including DNAStar, MEGA7.0 and Similarity plots3.5.1, was used for analysis of homology, genetic recombination and major amino acid variation sites.Results:The nucleotide and amino acid sequence homology of the whole-genome sequences of 45 CVA10 strains was 90.3%-99.1% and 97.9%-99.8%, respectively. The nucleotide sequence homology of P1 region was the highest (92.1%-100.0%), while the nucleotide sequence homology of P3 region ranged from 84.7% to 100.0%. In contrast to the diversity of nucleotide sequences, the amino acid sequences of each region were conserved. A phylogenetic analysis based on the complete VP1 sequences of CVA10 strains revealed eight genotypes: A-H. The CVA10 isolates in Jiangsu Province and other prevalent strains in China mainly belonged to genogroup C. Results of the phylogenetic analysis based on the whole-genome sequences and complete VP1 sequences were consistent. Phylogenetic analysis bases on different gene segments and Simplot recombination analysis revealed that Jiangsu isolates GD07/Lianyungang/2017 and N180/Suqian/2016 showed high homology with the CVA10 prototype in the P1 region, but had recombination sites with other strains of enterovirus group A in the P2, P3, 5′-UTR and 3′-UTR regions. Compared with the prototype strain AY421767/Kowalik/2004, the Jiangsu isolates showed frequent variations in the VP1 region and many other major amino acid sites, which might result in some imperceptible changes in capsid structure and potential receptor-binding sites.Conclusions:By analyzing the evolution and genetic recombination features of CVA10 strains at the genome level in Jiangsu Province, this study elucidated the influence of genetic recombination and amino acid site mutation on CVA10 infection, providing basic data for the prevention and control of hand-foot-mouth disease in Jiangsu Province.
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Objective:To investigate the molecular features of hand, foot and mouth disease (HFMD) caused by coxsackievirus A10 (CVA10) in Qingdao and analyze the clinical features of mild and severe cases.Methods:A total of 6 677 cases of HFMD routinely monitored by Qingdao Women and Children Hospital from 2014 to 2021 were enrolled. Throat swab samples were collected. Clinical data of these cases were retrospectively analyzed. Virus nucleic acid was extracted from the samples and the serotypes of enteroviruses were identified. The VP1 genes of CVA10 strains were amplified and sequenced. A phylogenetic tree based on the VP1 gene sequences was constructed using MEGA7. 0 software. SPSS23.0 software was used for statistical analysis.Results:There were 285 cases positive for CVA10, including 183 males and 102 females, and children under five years old accounted for 89.8%. Most of CVA10 infection occurred between the months of April to September. The count of white blood cells, the percentage of neutrophils, the concentration of hemoglobin, and the levels of aspartate aminotransferase and alanine transaminase were significantly higher in severe patients than in mild patients. Besides, chest radiography and brain CT revealed more abnormalities in severe patients, and the duration of ECG monitoring was longer in them. Compared with mild cases, severe cases developed rash early than fever with rash mostly on buttocks ( P<0.05). Phylogenetic analysis showed that most of the CVA10 strains circulating in Qingdao between 2014 and 2021 belonged to clade Ⅰ, and there were two variations A23V and I283V in the amino acid sequence of clade Ⅰ. Conclusions:This study showed that children of all ages were susceptible to CVA10, especially those under five years old. CVA10 showed complex and diverse epidemic trends in different regions and years.
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@#Abstract: Objective To analyze the results of the surveillance of hand, foot and mouth disease (HFMD) pathogens in Baoshan City, Yunnan Province in 2022, and to analyze the genetic characteristics of the main epidemic strain coxsackievirus A16 (CVA16), in order to provide scientific basis for the prevention and control of HFMD. Methods Samples of hand, foot and mouth disease cases in Baoshan City submitted to Yunnan Province in 2022 were selected, the samples were processed, and the viral nucleic acid was extracted, and the Enterovirus (EV) VP4/VP2 binding region gene was amplified with primers (MD91/OL68-1) and sequenced. The sequence was BLAST searched in GenBank to determine the virus type, and then the full sequence of VP1 region was amplified with relevant primers of each type of virus and sequenced. Viruses were identified by using Enterovirus Genotyping Tool Version 1.0. according to the reference documents, the reference sequences were downloaded for making the phylogenetic tree, and the test results were statistically analyzed. Results A total of 307 clinical samples of hand-foot-mouth disease in Baoshan City in 2022 were detected by real-time RT-PCR. There were 280 laboratory-confirmed cases (91.21%), among which the detection rate of CVA16 was 55.05% (169/307), EV-A71 was 3.58% (11/307), and other enteroviruses were 32.57% (100/307). Of the 206 HFMD test specimens, the VP4/VP2 junction and VP1 gene sequences of enterovirus were amplified and identified, and 29 enterovirus strains were obtained, with a positive virus rate of 14.08% (29/206). All viruses belonged to group A and were divided into 3 serotypes, which included 27 strains of CVA16 (93.10%, 27/29), 1 strain of EV-A71 (3.45%, 1/29), and 1 strain of CVA10 (3.45%, 1/29). Group B, C, and D viruses were not detected. The positive rate of VP4/VP2 binding region and VP1 region of coxsackievirus A16 gene in Baoshan City in 2022 was 13.11% (27/206). The genetic evolution analysis showed that the 27 strains of CVA16 belong to B1a subtype and can be divided into two evolutionary branches. Conclusions In 2022, the main epidemic strain of HFMD in Baoshan City, Yunnan Province is CVA16 gene, belonging to B1a subtype, which can be divided into two branches, indicating 2 transmission chains prevalent in Baoshan City. Future efforts should focus on strengthening surveillance, improving the quality of monitoring, and understanding the characteristics of viral prevalence..
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@#Abstract: Objective To genotype and analyze whole genomic features of Coxsackievirus B3 (CVB3) isolated in Tianjin, to improve evolution information of CVB3 virus in Tianjin, and to provide basis for surveillance and early warning of related diseases. Methods Viral RNA was extracted from five CVB3 strains isolated in Tianjin, whole genome sequence of the virus was amplified by RT-PCR and sequenced by next-generation sequencing method, and phylogenetic and recombinant analysis were carried out. Results The open reading frame 1(ORF) of the five CVB3 strains contained 6 555 nucleotides and encoded 2 185 amino acids, and ORF2 was composed of sequences encoding 68 amino acids. The nucleotide sequence similarity ranged from 78.3%-100%, and the amino acid sequence similarity ranged from 95.7%-100%. Compared with the CVB3 prototype strain, the nucleotide sequence similarity of the five viruses was between 78.2%-79.1%, and the similarity of amino acid sequences was 94.9%-95.3%. All five viruses exhibited a T151A mutation on the VP2 protein. Additionally, the encephalitis isolate showed a K158E mutation on the VP2 protein, while one of the sewage isolates had a C234T mutation in 5' noncoding region. The five strains belonged to two different genotypes, among which the encephalitis isolate in 2016 belonged to the D genotype, while the sewage isolates in 2021 belonged to the E genotype. This is also the first report of E genotype CVB3 in northern China. The CVB3 strain may have recombinant events in non-structural protein regions, in which encephalitis isolate may recombine with a Coxsackievirus B5 (CVB5) strain, while sewage isolates may have recombinant events with a strain of ECHO virus 18 (E18). Conclusions The CVB3 isolates in Tianjin belong to D and E genotypes, and recombination events may exist in non-structural protein region of the viral genome. The results of CVB3 virus genome analysis in sewage suggests presence of CVB3 infection in the population of Tianjin, and its epidemic dominant genotype may have changed.
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SUMMARY OBJECTIVE: This study aimed to test the hypothesis that fibromyalgia is associated with a human enteroviral infection. METHODS: Venous peripheral blood samples from 27 patients fulfilling the American College of Rheumatology revised diagnostic criteria for fibromyalgia and from 26 age- and sex-matched controls, who underwent immunofluorescence assays for coxsackievirus A7 IgG, coxsackievirus B1 IgG, coxsackievirus A7 IgA, coxsackievirus B1 IgA, echovirus IgG, and echovirus IgA. These immunological tests were performed blind to group status. RESULTS: There were no significant differences between the patient and control groups in respect of positive results for coxsackievirus A7 IgG (p=0.467), coxsackievirus B1 IgG (p=0.491), coxsackievirus A7 IgA (p=0.586), coxsackievirus B1 IgA (p=0.467), echovirus IgG (p=0.236), and echovirus IgA (p=1). CONCLUSIONS: The results of this systematic study do not support the hypothesis that fibromyalgia is associated with infection by a human enterovirus.
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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 analyze the etiological characteristics of hand, foot and mouth disease (HFMD) cases and to investigate the genetic characteristics of VP1 region of coxsackievirus A6 (CVA6) and CVA16 strains in Wenshan prefecture of Yunnan Province in 2020.Methods:Virus RNA was extracted directly from stool samples of children with HFMD in Wenshan prefecture of Yunnan Province in 2020. Enterovirus (EV) VP4/VP2 junction region was amplified using MD91/OL68-1 primers and sequenced, and then the serotypes of EV isolates were preliminarily identified. Amplification and sequencing of the complete VP1 gene were performed. A phylogenetic tree was constructed by MEGA 5.2 software with the reference strains from GenBank. Genetic and molecular epidemiological characteristics of CVA6 and CVA16 were analyzed.Results:Thirty-two strains of EV and one strain of astrovirus MLB1 were detected in 317 specimens with an overall virus detection rate of 10.41% (33/317). Among the 32 EV strains, 31 (96.88%) were enterovirus species A (EVA) and one (3.12%) was EVB. EVC and EVD were not detected. CVA6 was the predominant EV, accounting for 62.50% (20/32), followed by CVA16 (18.75%, 6/32), CVA4 (9.37%, 3/32) and CVA10 (3.12%, 1/32). EVA71 was not detected. The phylogenetic analysis showed 20 CVA6 strains belonged to D3a sub-genotype and could be further divided into three clusters. Six CVA16 strains belonged to B1a sub-genotype, which was one of the predominant genotypes circulating in China, and could be divided into two clusters.Conclusions:The detection rate of pathogens causing HFMD in Wenshan prefecture in 2020 was 10.41% and the most common etiologic agents were CVA6 and CVA16. Based on the genetic analysis of the VP1 gene, the predominant genotype circulating in Wenshan prefecture in 2020 was CVA6 D3a sub-genotype, followed by CVA16 B1a sub-genotype. EVA71 was not detected.
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Objective:To investigate the serotypes and epidemic characteristics of non-polio enteroviruses (NPEV) in acute flaccid paralysis (AFP) cases in Henan Province in 2021.Methods:Fecal specimens of 529 AFP cases reported in Henan Province in 2021 were collected for virus isolation. The VP1 regions of NPEV were sequenced. MEGA5.1 software was used for sequence alignment and a phylogenetic tree was constructed as well. The epidemiological data were organized and statistically analyzed using Excel2016 and SPSS26 software.Results:A total of 30 strains of NPEV were isolated from the fecal specimens of 529 AFP cases, with an isolation rate of 5.67% (30/529). They were belonged to group A and group B with 15 strains in each group, and no group C or group D viruses were isolated. Group A contained six serotypes and was dominated by coxsackievirus A2 (CVA2) and CVA6. Group B contained tree serotypes and was dominated by CVB3. In the population distribution, the separation rate of NPEV was the highest among children under 5 years old, which was 76.67% (23/30), and the ratio of male to female was 1.51∶1. In the regional distribution, group A viruses were mainly distributed in the central, southern and southwestern parts of Henan Province with CVA2 and CVA4 being the most widely distributed, while group B viruses were relatively concentrated, mainly distributed in the central, northern and southwestern parts of Henan Province with CVB3 being the predominant. In terms of time distribution, NPEV could be isolated throughout the year except from January to February, showing the epidemic characteristics of high incidence in spring and summer and low incidence in autumn and winter. The peak of group A virus infection was in May and the peak period of group B virus infection was from June to July.Conclusions:CVB3 was the main serotype of NPEV isolated in Henan Province in 2021. The pathogenic spectrum and regional distribution of NPEV had changed significantly compared with those in 2018-2019. In order to provide reference for the diagnosis and surveillance of AFP and maintain the polio-free status in Henan Province, much attention should be paid to the current epidemic trend of NPEV.