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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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@#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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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 analyze the etiology of hand, foot and mouth disease (HFMD) cases collected from Wenshan prefecture from 2014 to 2018 and the molecular epidemiology of coxsackievirus A6(CV-A6).Methods:Viruses were isolated by RD cells and Hep-2 cells from stool samples collected from HFMD patients in Wenshan prefecture from 2014 to 2018. Virus RNA was extracted and virus VP4/VP2 junction region sequence was firstly amplified and sequenced by MD91 and OL68-1 primer pairs, then the virus serotype was determined. Virus entire VP1 gene sequences were determined by relative primer pairs according to the references. The reference sequences of CV-A6 virus entire VP1 gene were downloaded from the GenBank and the phylogenetic tree was constructed and the genetic characteristics and molecular epidemiology were analyzed.Results:During five years of study period, a total of 581 strains of enteroviruses (EVs) was isolated with an isolation rate of 20.40% (581/2 848). Among 581 strains, 74 strains were CV-A6, accounting for 12.74% (74/581); 124 were CV-A16, accounting for 21.34% (124/581); 374 were EV-A71, accounting for 64.37% (374/581); nine were other EVs, accounting for 1.55% (9/581). The entire VP1 sequences of 74 CV-A6 strains were filtered by constructing a phylogenetic tree and the completely same strains were excluded from analysis. We finally analyzed the phylogenetic characteristics of 22 strains isolated in this study with 52 reference strains. The results showed that all 22 Wenshan strains belonged to D3a sub-genotype, of which 21 strains belonged to cluster 1, and only one strain belonged to cluster 2.Conclusions:From 2014 to 2018, the outbreaks of HFMD in Wenshan prefecture were mainly caused by EV-A71, CV-A16 and CV-A6, accounting for 64.37%, 21.34% and 12.74% respectively. Phylogenetic analysis showed, similar to the situation in China, the sub-genotype D3a of CV-A6 was the predominant virus and the cluster 1 was the main sub-genotype in this outbreak.
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@#Hand, foot, and mouth disease (HFMD) is a common childhood disease caused by enteroviruses. In 2018, a HFMD outbreak in Malaysia affected over 76,000 children. In this study, we used RT-qPCR and CODEHOP PCR to detect the causative agents in 89 clinically diagnosed HFMD patients in Kuala Lumpur and Selangor. Most (62.9%) of the children were below 3 years old. PCR with either assay detected enteroviruses in 84.2% (75/89) and CODEHOP PCR successfully typed 66.7% (50/75) of the enteroviruses. Sequencing of CODEHOP amplicons showed co-circulation of multiple enteroviruses with coxsackievirus A6 (CV-A6) and A16 as the predominant serotypes, but not the neurovirulent enterovirus A71. CV-A6 infection was more common in children less than 12 months old (p=0.01) and was more likely to cause vesicles in the gluteal area (p=0.01) compared to other enteroviruses. Establishing a robust identification method during HFMD outbreaks is important for patient management and public health responses.
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La enfermedad mano-pie-boca (EMPB) típica es exantemática, con sintomatología clásica de fiebre, exantema papulovesicular en las manos y los pies, asociada o no a herpangina. Es causada, principalmente, por enterovirus 71 y virus Coxsackie A16, miembros del género Enterovirus. En los últimos años, se han descrito brotes mundiales de EMPB con manifestaciones atípicas causadas, sobre todo, por el virus Coxsackie A6. La EMPB atípica se considera emergente con características clínicas y epidemiológicas peculiares: la afección de adultos, el predominio en invierno y un amplio espectro de manifestaciones clínicas en la extensión y la distribución de las lesiones. Las características morfológicas de las lesiones son muy variables: pueden simular varicela, impétigo o vasculitis.Se describe el caso de un niño de 4 años con EMPB atípica. Se detalla su forma de presentación, evolución clínica, metodología diagnóstica y terapéutica empleada.
Typical hand-foot-mouth disease (HFMD) is an exanthematous viral disease with a classic symptomatology of fever, papulovesicular rash on the hands and feet with or without herpangina. It is usually caused by enterovirus 71 and Coxsackievirus A16, members of the genus Enterovirus. Recently, worldwide outbreaks of HFMD with atypical manifestations caused by Coxsackievirus A6 have been described. Atypical HFMD is considered an emerging disease due to its peculiar clinical and epidemiological characteristics: it affects adults, has a wide spectrum of clinical manifestations in the extension and distribution of the lesions and occurs in winter. The morphological characteristics of the lesions are very variable and can be misdiagnosed as chickenpox, impetigo or vasculitis. Here we describe the symptoms, clinical evolution, diagnostic methodology and treatment employed on a 4-year-old male patient with atypical HFMD.
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Humanos , Masculino , Pré-Escolar , Enterovirus Humano A/classificação , Doença de Mão, Pé e Boca/diagnóstico , Infecções por Coxsackievirus/epidemiologia , Diagnóstico Diferencial , Genótipo , Doença de Mão, Pé e Boca/terapiaRESUMO
We present two groups of cases of atypical hand, foot, and mouth disease (HFMD) caused by Coxsackievirus A6 (CV-A6) detected in Argentina in 2015. The first group involved 14 patients from Chubut province and the second group affected 12 patients from San Luis province. Molecular analysis of the complete VP1 protein gene revealed the circulation of E2 sublineage, the most predominant worldwide. To our knowledge, this is the first report of CV-A6 infections associated with atypical HFMD in Argentina and South America.
Se describen dos grupos de casos de enfermedad de mano-pie-boca (HFMD) atípica causada por el virus Coxsackie A6 (Coxsackievirus A6, CV-A6) detectados en Argentina en el año 2015. El primero de los grupos involucró a 14 pacientes de Chubut y el segundo a 12 pacientes de San Luis. El análisis molecular del gen de la proteína VP1 completa reveló la circulación del sublinaje E2, el predominante a nivel global. Hasta donde sabemos, este es el primer reporte de infecciones CV-A6 asociadas con HFMD atípica en Argentina y Sudamérica.
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Enterovirus/patogenicidade , Doença de Mão, Pé e Boca/etiologia , Doença de Mão, Pé e Boca/microbiologia , Doença de Mão, Pé e Boca/epidemiologiaRESUMO
Objective To analyze the biological characteristics of clinical isolates of coxsackievir-us A6 (CVA6), a pathogen of hand,foot and mouth disease (HFMD), and to provide reference for vaccine development. Methods CVA6 strains were isolated from 21 stool and throat swab specimens of patients with HFMD in Yunnan Province and then identified. Their growth characteristics, plaque morphology and virulence to suckling mice were analyzed. Results Five CVA6 strains, named CVA6-129, CVA6-113, CVA6-57, CVA6-94 and CVA6-162, were isolated and all belonged to D3 subtype. Only the CVA6-129 strain could proliferate rapidly in Vero and KMB17 cells and the proliferation peaked 30 h after inoculation. The infectious titer of the CVA6-129 strain was 7. 54 lgCCID50 (50％ cell culture infective dose) / ml in KMB17 cells. Different morphologies of plaques were formed by the CVA6-129 strain in Vero and KMB17 cells at the same time points, which were small and round with clear edges in Vero cells, and large and irregular with blurry edges in KMB17 cells. Suckling mice were susceptible to CVA6 via intramuscular and intraperito-neal injection. The most common symptoms in infected suckling mice were reduced mobility, hind limb pa-ralysis and quadriplegia. CVA6 infection could result in death in severe cases. Conclusions This study isolated five CVA6 strains from a number of clinical samples of suspected HFMD cases, of which the CVA6-129 strain showed potential as a vaccine candidate.
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Objective To analyze the genetic characteristics of VP1-VP4 genes carried by cox-sackievirus A6 (CVA6) strains isolated from severe cases of hand, foot, and mouth disease (HFMD) in Shenzhen during 2012 to 2015. -ethods The VP1-VP4 genes of CVA6 strains isolated from severe HFMD cases in Shenzhen during 2012 to 2015 were amplified and sequenced. Phylogenetic analysis was performed to analyze the VP1-VP4 genes of CVA6 isolates and sequences downloaded from GenBank by using DNASTAR6. 0 and MEGA6. 02 software packages. Results Four cases of severe HFMD were caused by CVA6 in Shenzhen during 2012 to 2015. All of the patients had the symptom of fever, skin rash and aseptic encephalitis. The CVA6 strain causing severe HFMD in 2013 shared 98. 8％-98. 9％ homology in nucleotide sequences and 99. 3％-99. 8％ in amino acid sequences with the strains isolated in 2012. Two amino acid mutations were found in the CVA6 strain isolated in 2013, which were G73E in VP2 region and S13G in VP1 region. However, the CVA6 strain isolated in 2015 only shared 95. 0％ homology in nucleotide sequences and 99. 3％ homology in amino acid sequences with the strain isolated in 2013. Six amino acid mutations were identified including E73G in VP2 region and T5A, S27N, A30V, N137S and V242I in VP1 region. The phylogenetic analysis revealed that the four CVA6 strains belong to D3 sub-genotype. The CVA6 strains causing severe cases in 2012 had the nearest genetic relationship with the strain isolated in Changsha in 2012 (KJ156349). The CVA6 strain isolated in Shenzhen in 2013 had the nearest genetic relationship with the strain isolated in Shanghai in 2013 (KJ612513). The Shenzhen CVA6 isolate in 2015 showed high similarity to Weifang CVA6 isolate in 2014 (KX752785). Conclusions All CVA6 strains causing severe HFMD ca-ses in Shenzhen during 2012 to 2015 belongs to D3 sub-genotype. Mutations of S27N and A30V in the VP1 region of the CVA6 isolate in 2015 are located in the B cell epitopes. In addition, the VP1-V242I mutation in the CVA6 strain isolated in 2015 is located in the binding site of PSGL-1 receptor. These mutations may affect the binding of CVA6 strains to the cellular receptors and their infectivity to people.
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Objective To detect the enterovirus VP4 and VP1 genes in 510 stool samples collect-ed from hand, foot and mouth disease ( HFMD) cases and analyze the phylogenetic characteristics of the en-tire VP1 genes of coxsackievirus A6 (CV-A6) strains in six prefectures/cities of Yunnan Province in 2018. Methods Viral RNA was abstracted from the stool samples. VP4 gene sequences were amplified by RT-PCR and sequenced using the MD91/OL68-1 primer pair to identify viral genotypes. Whole VP1 gene se-quences were amplified and sequenced using appropriate primer pairs. The whole VP1 gene sequences of CV-A6 reference strains were downloaded from GenBank. MEGA5. 2 software was used to analyze the simi-larity in nucleotide and amino acid sequences between different strains and phylogenetic tree was constructed for analysis of genetic characteristics and molecular epidemiology. Results VP4 and VP1 gene sequences were obtained from 57 out of 510 stool samples with a positive rate of 11. 17％ (57/510). There were 43 CV-A6 (8. 43％, 43/510), six CV-A10 (1. 17％, 6/510), two enterovirus A71 (EV-A71, 0. 39％, 2/510) and two CV-A9 (0. 39％, 2/510) strains. The other four strains were CV-A4 (0. 19％, 1/510), CV-A5 (0. 19％, 1/510), CV-B1 (0. 19％, 1/510) and E11 (0. 19％, 1/510). The phylogenetic analy-sis showed that all 43 CV-A6 strains belonged to sub-genotype D3. Conclusions In the 510 HFMD sam-ples, CV-A6 strains were mostly detected with a detection rate of 8. 43％ and accounted for 75. 44％ (43/57) of all isolates, followed by CV-A10 (1. 17％, 6/510) and EV-A71 (0. 39％, 2/510). There was a large HFMD outbreak mainly caused by CV-A6 in Yunnan Province in 2018. The outbreak was caused by CV-A6 of sub-genotype D3, as was the case with pervious outbreaks in China.
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Objective To understand the etiological and clinical characteristics of children with severe hand,foot and mouth disease (HFMD) in Xi'an in 2018,and to provide the evidence for clinical diagnosis and treatment.Methods The children with severe HFMD admitted at Xi'an Children's Hospital from January to December 2018 were selected as the research objects.Clinical data were collected,and the anal swab were detected by adopting real time (RT)-polymerase chain reaction(PCR).Results Ninety-five cases of HFMD were treated in Xi'an Children's Hospital in 2018,of which 92 cases were severe and 3 cases were critical.Eighty-seven cases were positive for enterovirus nucleic acid,30 cases were enterovirus 71 (EV71) (31.6％),39 cases were coxsackievirus A6 (CA6) (41.0％),3 cases were CA16 (3.2 ％),2 cases were CA 10 (2.1％) and 13 cases were other enteroviruses (13.7 ％).Among 95 patients,the ratio of male to female was 1.1 ∶ 1.0;the peak period of incidence of HFMD was from May to July,and the main age of onset of severe HFMD was under 3 years old.The main clinical manifestations were mental retardation,vomiting,irritability,lethargy and convulsion.Severe cases of CA6 are prone to convulsion.The main form of rash in CA6 cases was bullous rash,and demethylation may occur in recovery period.The rash in EV71 cases was small,thick,hard and few.After active treatment,only one child with EV71 infection died because of severe cerebral dysfunction,frequent convulsions and neurogenic pulmonary edema.The other child was discharged with hemiplegia and language dysfunction.The other severe children were cured and discharged from hospital.Conclusions In 2018,CA6 was the main pathogen of severe HFMD in Xi'an,with bullae was the main manifestation of skin rash,and nail removal could occur during convalescence.Critical and death cases were still caused by EV71.
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Objective@#To understand the etiological and clinical characteristics of children with severe hand, foot and mouth disease (HFMD) in Xi′an in 2018, and to provide the evidence for clinical diagnosis and treatment.@*Methods@#The children with severe HFMD admitted at Xi′an Children′s Hospital from January to December 2018 were selected as the research objects.Clinical data were collected, and the anal swab were detected by adopting real time(RT)-polymerase chain reaction(PCR).@*Results@#Ninety-five cases of HFMD were treated in Xi′an Children′s Hospital in 2018, of which 92 cases were severe and 3 cases were critical.Eighty-seven cases were positive for enterovirus nucleic acid, 30 cases were enterovirus 71(EV71)(31.6%), 39 cases were coxsackievirus A6(CA6) (41.0%), 3 cases were CA16(3.2%), 2 cases were CA10(2.1%) and 13 cases were other enteroviruses (13.7%). Among 95 patients, the ratio of male to female was 1.1∶1.0; the peak period of incidence of HFMD was from May to July, and the main age of onset of severe HFMD was under 3 years old.The main clinical manifestations were mental retardation, vomiting, irritability, lethargy and convulsion.Severe cases of CA6 are prone to convulsion.The main form of rash in CA6 cases was bullous rash, and demethylation may occur in recovery period.The rash in EV71 cases was small, thick, hard and few.After active treatment, only one child with EV71 infection died because of severe cerebral dysfunction, frequent convulsions and neurogenic pulmonary edema.The other child was discharged with hemiplegia and language dysfunction.The other severe children were cured and discharged from hospital.@*Conclusions@#In 2018, CA6 was the main pathogen of severe HFMD in Xi′an, with bullae was the main manifestation of skin rash, and nail removal could occur during convalescence.Critical and death cases were still caused by EV71.
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Objective@#To detect the enterovirus VP4 and VP1 genes in 510 stool samples collected from hand, foot and mouth disease (HFMD) cases and analyze the phylogenetic characteristics of the entire VP1 genes of coxsackievirus A6 (CV-A6) strains in six prefectures/cities of Yunnan Province in 2018.@*Methods@#Viral RNA was abstracted from the stool samples. VP4 gene sequences were amplified by RT-PCR and sequenced using the MD91/OL68-1 primer pair to identify viral genotypes. Whole VP1 gene sequences were amplified and sequenced using appropriate primer pairs. The whole VP1 gene sequences of CV-A6 reference strains were downloaded from GenBank. MEGA5.2 software was used to analyze the similarity in nucleotide and amino acid sequences between different strains and phylogenetic tree was constructed for analysis of genetic characteristics and molecular epidemiology.@*Results@#VP4 and VP1 gene sequences were obtained from 57 out of 510 stool samples with a positive rate of 11.17% (57/510). There were 43 CV-A6 (8.43%, 43/510), six CV-A10 (1.17%, 6/510), two enterovirus A71 (EV-A71, 0.39%, 2/510) and two CV-A9 (0.39%, 2/510) strains. The other four strains were CV-A4 (0.19%, 1/510), CV-A5 (0.19%, 1/510), CV-B1 (0.19%, 1/510) and E11 (0.19%, 1/510). The phylogenetic analysis showed that all 43 CV-A6 strains belonged to sub-genotype D3.@*Conclusions@#In the 510 HFMD samples, CV-A6 strains were mostly detected with a detection rate of 8.43% and accounted for 75.44% (43/57) of all isolates, followed by CV-A10 (1.17%, 6/510) and EV-A71 (0.39%, 2/510). There was a large HFMD outbreak mainly caused by CV-A6 in Yunnan Province in 2018. The outbreak was caused by CV-A6 of sub-genotype D3, as was the case with pervious outbreaks in China.
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Objective@#To study infection of coxsackievirus A6 (CV-A6) in Mongolian gerbils.@*Methods@#To screen the optimal ages of Mongolian gerbils, five groups with different ages were infected with 1×105 TCID50 dose of CV-A6 XS45 strain by intraperitoneal, and symptom scores of Mongolian gerbils were collected. Then to estimate the dose-effect, three doses of virus were injected to the Mongolian gerbils. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry(IHC) were used to determine virus load and tissues infection in muscle, brain and intestinal tract.@*Results@#Mongolian gerbils infected with 1×105 TCID50 dose CV-A6 consistently exhibited clinical signs, and the morbidity (death) rates of five age groups were up to 100%. There was a positive correlation between the trend of symptom scores changes and ages. The morbidity (death) rates of three doses (1×103 TCID50, 1×104 TCID50, 1×105 TCID50) also were up to 100% in 28 days Mongolian gerbils. The correlation between the trend of symptom scores changes and doses were negative. Virus loads were detected in muscle, brain and intestinal tract of pathogenesis animal. The virus loads of muscle were higher than others. IHC results showed virus infection and cytopathic effects in three tissues.@*Conclusions@#Mongolian gerbils had high susceptibility to CV-A6, and were best for animal model of CV-A6 infection.
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Objective@#To analyze the clinical characteristics of hand, foot and mouth disease (HFMD) caused by coxsackievirus A6 (CV-A6) in different age groups.@*Methods@#From January 2015 to December 2017, throat swabs were collected from children with or suspected of having HFMD then quantitative real-time PCR was performed to detect enterovirus nucleic acid. HFMD cases caused by CV-A6 were divided into different groups according to age for comparison.@*Results@#In total, there were 467 cases of HFMD caused by CV-A6 with the age ranging from 3 months to 16 years. There were 273 cases in the infants and young children group (< 3 years old), 131 cases in the pre-school group (3-6 years old), and 63 cases in the school-age group (> 6 years old). The peak incidence was found between May and November.Fever was the common symptom, and the rate of fever in infant group was the highest (220/273, 80.5%); The proportion of cases with leucocyte elevation in the infant group was the highest (127/273, 46.5%) than that in the school-age group (17/63, 27.0%) with a statistical significance. The skin erythra of the HFMD caused by CV-A6 were diverse in forms. Over two forms of skin erythra accounted for 53.9% (257/476) of all cases, and the cases in the infant group showing more forms of skin erythra (163/273, 59.7%). The oral herpes were mainly distributed in the upper palate and pharyngeal isthmus, but the school age group had the least number of distribution sites (0.89±0.86). The cases in the infant group showed higher incidence of skin rash at the elbow joint (109/273, 39.9%), knee (88/273, 32.6%), thigh (112/273, 41%), buttock (122/273, 44.7%) than the other two groups, However, the school age group showed lower incidence of skin rash in the lower leg (0/63, 0%) and thigh (6/63, 9.5%) than the other two groups. The differences between groups were statistically significant. All cases were cured clinically, no severe cases occurred. Among the 288 cases followed up for 6 months, 33 (33/288, 11.5%) suffered from nail exfoliation.@*Conclusions@#Different age groups of HFMD caused by CV-A6 had different clinical manifestations. In the infant group, more cases had fever and the erythra were more diverse in forms and wider in distribution. In addition, the increased leukocytes in routine blood test was also more common in the infant group.
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Objective@#To investigate the etiology spectrum of hand foot and mouth disease (HFMD) and to analyze the molecular characteristics of Coxsackievirus A10 and A6 in Qingdao in 2014.@*Methods@#Throat swabs of HFMD cases were tested for total enteroviruses (EVs), EV-A71, CV-A16, CV-A10 and CV-A6 by multiplex real time RT-PCR. Other EV serotypes were identified through the sequences of partial VP1 gene. The full-length of VP1 gene of CV-A10 and CV-A6 were amplified and sequenced. The sequences were phylogenetically analyzed using MEGA 5.0 software package.@*Results@#A total of 1727 HFMD patients were detected in 2014 and 11serotypes of enteroviruses were identified. EV-A71(38.0%, 410/1078), CV-A16(28.8%, 311/1078), CV-A10(14.1%, 152/1078)and CV-A6(3.2%, 34/1078)were the most dominant pathogen in 2014 in Qingdao. Proportions of CV-A10 in enterovirus infected children varied dramatically in different ages(χ2=15.19, P=0.001), showing a downtrend with age. Proportion of CV-A10 in inpatients was much higher than that in outpatients(χ2=49.1, P <0.001), while 60% of those inpatients showed nervous system damage symptoms, with pathological reflex or disappearance of physiological reflex. Phylogenetic analysis of complete VP1 sequences showed that all CV-A10 strains identied in this study belonged to genotype C, 71.7% of which located in branch C5; all CV-A6 strains belonged to genotype D while 83.3% of which located in branch D5.@*Conclusions@#EV-A71, CV-A16, CV-A10 and CV-A6 were the prevalent pathogens of HFMD in Qingdao in 2014. CV-A10 was more frequently detected in lower age group with HFMD, which can cause damage to nervous system. Strains of branch C5 in genotype C were the dominant strains of CV-A10 circulated in Qingdao in 2014 while strains of branch D5 in genotype D were the major strains of CV-A6.
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Objective@#To study the epidemiologic and genetic characteristics of coxackievirus A6(CV-A6) strains isolated in Shenyang.@*Methods@#Enterovirus strains positive for neither enterovirus A71 (EV-A71) nor CV-A16 were isolated from Shenyang during 2013 to 2017 to screen for CV-A6 isolates by real-time PCR. The entire sequences of viral genes encoding VP1 of CV-A6 positive samples were amplified and sequenced. The phylogenetic analysis was performed.@*Results@#CV-A6 strains accounted for 27.83% (575/2 066) of the non-EV-A71 and non-CV-A16 enterovirus strains isolated in Shenyang during the years 2013 to 2017. And CV-A6 strains were the predominant enterovirus strains with positive rate of 68.38 % (240/351) in 2015. The CV-A6 isolates from Shenyang during 2013 to 2017 could be classified into the cluster D3a in the phylogenetic tree. Subtype D3a.1 strains circulated during 2013 to 2014 and subtype D3a.2 strains circulated during 2015 to 2017.@*Conclusions@#CV-A6 strains were the predominant enterovirus strains among non-EV-A71 and non-CV-A16 enterovirus strains circulated in Shenyang from 2013 to 2017. The CV-A6 isolates from Shenyang during 2013 to 2017 could be classified into the cluster D3a in the phylogenetic tree and subtype D3a.2 strains were evolved from subtype D3a.1 strains.
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Objective:To predict the basic physicochemical properties ,structure and function ,and linear B-cell epitopes of the capsid protein VP1 of coxsackievirus A6(CVA6).Methods: The amino acid sequence of the CVA6 VP1 was analyzed using Bioedit software and various online tools including SubLoc ,TargetP and the others from ExPASy Bioinformatics Resource Portal.Results: The CVA6 VP1 protein was a hydrophilic protein with a relative molecular weight of 33.6 kD and an isoelectric point of 7.92.This protein containsed 24 phosphorylation sites , but no signal peptide , transmembrane domains and possible fatty acylation sites.Its secondary structure was characterized by the richest random coils , and 48.52 percent of its amino acid residues exposed at the solution inter-face.Epitope prediction by Bepipred showed a number of potential B cell epitopes in the protein ,the highest antigenicity index among them located in the region of amino acids residue 155-165.Conclusion:The basic physicochemical properties ,structure and function characteristics ,and potential linear B-cell epitopes of CVA 6 VP1 were successfully predicted , which laid foundations for the further study on the protein and the preparation of vaccines and immunological diagnostic reagents for CVA 6 infection.
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This study bioinformatically analyzed the non-VP1 capsid proteins (VP2-VP4) of Coxasckievirus A6 (CVA6), with an attempt to predict their basic physicochemical properties, structural/functional features and linear B cell eiptopes. The online tools SubLoc, TargetP and the others from ExPASy Bioinformatics Resource Portal, and SWISS-MODEL (an online protein structure modeling server), were utilized to analyze the amino acid (AA) sequences of VP2-VP4 proteins of CVA6. Our results showed that the VP proteins of CVA6 were all of hydrophilic nature, contained phosphorylation and glycosylation sites and harbored no signal peptide sequences and acetylation sites. Except VP3, the other proteins did not have transmembrane helix structure and nuclear localization signal sequences. Random coils were the major conformation of the secondary structure of the capsid proteins. Analysis of the linear B cell epitopes by employing Bepipred showed that the average antigenic indices (AI) of individual VP proteins were all greater than 0 and the average AI of VP4 was substantially higher than that of VP2 and VP3. The VP proteins all contained a number of potential B cell epitopes and some eiptopes were located at the internal side of the viral capsid or were buried. We successfully predicted the fundamental physicochemical properties, structural/functional features and the linear B cell eiptopes and found that different VP proteins share some common features and each has its unique attributes. These findings will help us understand the pathogenicity of CVA6 and develop related vaccines and immunodiagnostic reagents.
Assuntos
Humanos , Sequência de Aminoácidos , Proteínas do Capsídeo , Genética , Alergia e Imunologia , Biologia Computacional , Enterovirus , Genética , Virulência , Epitopos de Linfócito B , Genética , Alergia e ImunologiaRESUMO
Objective To study the epidemic and genetic characteristics of coxsackievirus A6 ( CVA6) strains isolated in Guangdong province.Methods Enterovirus strains positive for neither entero-virus A71 ( EV71) nor CVA16 were isolated from Guangdong province during 2008 to 2013 to screen CVA6 isolates by real-time PCR.The entire sequences of viral genes encoding VP1 of CVA6 positive samples were amplified and sequenced.The phylogenetic analysis was performed to analyze the full-length gene sequences encoding VP1 of CVA6 isolates and sequences downloaded from GenBank by using DNAStar6.0 and MEGA5.2 software packages.Results CVA6 strains accounted for 61.4%of the 1672 non-EV71 and non-CVA16 enterovirus strains isolated in Guangdong province during year 2008 to 2013.The positive rates were respectively 10.5%(4/38), 66.7%(34/51), 36.2% (81/224), 63.0% (182/289), 62.3% (325/522) and 73.0%(400/548) from 2008 to 2013 and the differences among different years were significant (χ2=133.79, P<0.01).The CVA6 isolates could be classified into four clusters in the phylogenetic tree, designated A, B, C and D (including D1, D2 and D3 subgenogroups) genogroups.The four clusters shared nucleotide diversity ranging from 15.5% to 23.1%.The CVA6 strains isolated in Guangdong province shared 88.7%-100.0% homologies in nucleotide and 95.7%-100.0% in amino acid.Subtype D2 strains circulated during 2008 to 2012 and subtype D3 strains circulated during 2009 to 2013.Conclusion CVA6 strains were the predominant enterovirus strains among non-EV71 and non-CVA16 enterovirus strains circula-ted in Guangdong province from year 2008 to 2013.The CVA6 isolates could be classified into A, B, C and D genogroups based on the sequence analysis of VP1 region.Subgroups D2 and D3 isolates were identified and the subgroup D3 isolates were the prevalent strains in Guangdong.