2012‒2013年浙江省手足口病流行病学和病原学特征分析

摘要：目的 了解2012?2013年浙江省手足口病流行特征和病原构成,为手足口病防控工作提供参考。方法 收集2012?2013年浙江省手足口病疑似患者粪便、咽拭子、疱疹液标本,采用实时荧光RT-PCR对收集样本进行HFMD病原体检测。结果 2012?2013年共采集样本1 792例,患者以5岁以下散居儿童为主;浙江省手足口病发病高峰期在5~6月份,9月份出现发病次高峰;肠道病毒总检出率为72.9%,其中2012年浙江省手足口病优势病原体为EV71（40.3%）,其次为CoxA16（31.3%）,2013年浙江省手足口病优势病原体为其他肠道病毒（77.2%） （非EV71和CoxA16）,以CoxA6为主（51.3%）。不同样本类型中,肠道病毒检出率依次为疱疹液（100.0%）、粪便（76.2%）和咽拭子（65.1%）。结论 手足口病的流行具有季节性和人群性,不同年份引起手足口病的优势病原体存在变化,持续地病原监测有助于预防和控制手足口病的流行暴发。     

咸阳市2016-2019年手足口病病原学检测分析

本文通过对咸阳市2016-2019年手足口病(Hand,foot and mouth disease,HFMD)病原检测结果进行分析,阐明了咸阳市近四年HFMD病原谱的构成和流行特征,为HFMD防控工作提供依据.对2016-2019年收集的2711例HFMD病例标本进行荧光定量PCR检测确定肠道病毒型别,构建咸阳市HFMD病原谱并对阳性病例的流行特征进行描述性分析.2711例HFMD病例实验室确诊1444例(阳性率为53.26％),其中肠道病毒A组71型(Enterovirus 71,EV71)占病原谱构成的 12.74％、柯萨奇病毒 A组 16型(Coxsackievirus A16,CoxA16)占27.49％、柯萨奇病毒 A组 10型(Coxsackievirus A10,CoxA10)占5.19％、柯萨奇病毒 A 组6型(Coxsackievirus A6,CoxA6)占43.21％、其他肠道病毒(Enterovirus,EV)占11.36％.CoxA6和CoxA16交替居于咸阳市HFMD病原谱首位.咸阳市HFMD流行具有明显季节性和地区差异以及特定人群高发,夏季(5～7月)为发病主高峰,秋冬季(10～11月)为次高峰,主要集中在人口较多的市区,4岁以下散居儿童为易感人群,且男性发病率高于女性.今后的防控工作中应继续加强咸阳市HFMD监测,重视其他EV的监测工作,实时监测HFMD病原谱的变化.在高发季节,针对高发人群,采取积极有效干预措施,加强防控工作.     

2011—2014年百色市重症手足口病流行病学及病原学分析

目的了解2011—2014年百色市重症手足口病的流行病学及病原学特点,为预防和控制重症手足口病提供依据。方法收集2011—2014年百色市重症手足口病疫情资料,进行描述性流行病学分析;采用实时荧光定量PCR方法对手足口病重症病例标本进行肠道病毒通用型、肠道病毒71型和柯萨奇病毒A16型核酸检测。结果2011—2014年百色市共报告手足口病105 900例,其中重症手足口病537例,重症率为0.51%;死亡35例,病死率为0.03%。重症手足口病发病主要集中在每年的4—5月;3岁以下重症病例占重症病例总数的88.27%,男女性别比为1.44∶1;散居儿童是主要的发病人群(75.98%);患者主要集中在平果县、田东县、田阳县、右江区等右江河谷一带;重症手足口病阳性患者中,肠道病毒71型占77.51%,柯萨奇病毒A16型占5.15%,其他肠道病毒占17.34%。结论 2011—2014年百色市重症手足口病多发于3岁以下的散居儿童,发病季节主要集中在4—5月,病原体以肠道病毒71型为主。     

1858例手足口病疫情监测分析

目的探讨手足口病疫情的流行特征。方法对我院2012年1～8月份报告的1858例手足口病患儿的临床资料进行回顾性分析。结果 1858例手足口病中,重症78例,死亡3例;重症病例咽、肛拭子采样检测,EV71感染76例,2例为其它肠道病毒感染;发病年龄3岁以下儿童占89%。发病男女性别比为1.62∶1;病例报告集中在5、6月份。结论在疫情流行期间加强手足口病防控工作及疫情监测,强化各级医务人员培训,早期识别重症患儿,可最大限度降低病死率。     

2007年北京地区儿童手足口病病原的初步筛查

2007年4～6月儿童手足口病流行期间,对北京地区51例皮损症状典型、伴/不伴发热、无重症合并症的手足口病患儿采样,建立RT-PCR方法,以5'非编码区(5'UTR)肠道病毒通用引物、CA16和EV71 VP1区特异性引物直接对82份临床标本进行了初步筛查,肠道病毒阳性率达70.6%。检测病例中CA16阳性25例(25/51)、EV71阳性4例(4/51)、非CA16和EV71的肠道病毒阳性病例7例(7/51),三者比例约为6:1:2。2007年北京地区儿童轻症手足口病主要病原包括CA16和EV71,同时还存在一定比例其它肠道病毒。部分EV71毒株经测序验证及系统进化分析显示为C4基因亚型。     

2009—2019年平顶山市手足口病流行特征分析

目的分析2009—2019年平顶山市手足口病(hand-foot-mouth disease, HFMD)流行特征,为今后本地制定防控措施提供依据。方法对中国疾病预防控制信息系统报告的平顶山市2009—2019年HFMD病例信息进行描述性流行病学分析。结果 2009—2019年平顶山市共有HFMD报告病例53 477例,重症病例5 878例,死亡16例,年均发病率为109.70/10万,重症比例为10.99%,年均死亡率为0.03/10万。2010年和2014年出现了2次HFMD大规模流行。城市市区发病率明显高于郊县。报告病例时间分布呈现明显的春、夏季节性高发,呈单峰分布,4—5月出现高峰。人群分布情况,男性明显多于女性;报告病例集中在0～5岁组儿童,有50 557例,占94.54%;人群散居儿童报告病例较多,有40 352例,占75.46%。病原学特征以肠道病毒71型(Enterovirus71, EV71)阳性为主,HFMD病原谱有一定变化,EV71阳性构成比自2015年以来逐渐降低,EV71构成比的变化与重症比例呈正比例变化,两者呈正相关(r=0.876),差异有统计学意义(P0.05)。全市聚集性疫情的发生与HFMD疫情的整体趋势一致,而幼托机构是聚集性发生的主要场所。接种肠道病毒71型灭活疫苗(简称EV71疫苗)的HFMD病例中无EV71阳性病例,接种EV71疫苗和未接种疫苗病例的EV71阳性检出率差异无统计学意义(χ~2=2.517、P=0.113,P0.05)。结论在HFMD流行季节,须加强5岁以下儿童及托幼机构等场所的防控工作,减少聚集性疫情的发生,推广EV71疫苗接种是控制HFMD疫情的关键。     

人肠道病毒71型与手足口病的分子流行病学及其分子进化

人肠道病毒71血清型(Enterovirus 71, EV71)是手足口病(Hand, foot and mouth disease, HFMD)的主要病原体之一,除了引起手、足和口腔等部位出现疱疹的手足口病典型症状,还能引起无菌性脑膜炎和急性迟缓性麻痹等神经系统并发症并致死亡。EV71在历史上曾经造成多起手足口病疫情,尤其是1997年之后,在亚太地区发生了大规模的手足口病疫情,造成了大量的手足口病病例和死亡病例。手足口病尚无上市疫苗和抗病毒药物,主要依赖对症治疗,因此对EV71的分子流行病学和分子进化研究对手足口病的监测和防控具有重要意义。文章对EV71基因型的分类、时空分布、进化特征和模式以及所造成的代表性疫情进行了综述,为EV71致病机制、抗病毒药物和疫苗的研究以及对手足口病疫情的监测和防控提供启发。     

怀化市2008—2015年手足口病流行病学特征分析

目的分析怀化市2008—2015年手足口病的流行病学特征,为制定本地区手足口病的防控措施提供科学依据。方法采用描述性流行病学方法,对怀化市2008—2015年报告的手足口病病例进行流行病学特征及病原学检测分析。结果怀化市2008—2015年共报告手足口病病例46 333例,每年发病率分别为51.04/10万、33.40/10万、98.85/10万、84.79/10万、181.96/10万、126.44/10万、269.57/10万、125.95/10万。共报告重症病例601例,重症病例发生率占比1.30%,报告死亡病例8例,病死率占比0.02%。在此期间怀化市所有县市区均有病例报告,年均发病率较高的分别是鹤城区252.86/10万、中方县159.48/10万、洪江区152.27/10万、芷江县130.13/10万。每年4—6月和10—12月为发病高峰期;0~3岁儿童是发病重点人群,该年龄段发病数占总报告病例数85.07%;男女性别比1.8∶1。在2 880份实验室确诊病例中肠道病毒71型阳性1 915例,柯萨奇病毒A16型阳性380例,其他肠道病毒阳性585例,2015年其他肠道病毒阳性占比升至43.43%。结论怀化市手足口病在高发季节应继续采取综合防控措施,控制疫情的流行和暴发。     

新乡地区2011年肠道病毒71型VP1基因特征分析及手足口病流行特点

为了解新乡地区2011年肠道病毒71型(EV71)VP1基因特征及手足口病流行特点,采用荧光RT-PCR对临床诊断的粪便标本进行总肠道病毒(EV)、柯萨奇病毒A16(CA16)和EV71检测;选取10例EV71阳性标本进行VPl序列扩增并测序,所得序列进行同源性分析和构建系统发生树;对2011年新乡市手足口病疫情监测数据进行分析。结果显示,重症标本的EV71阳性率(73%)显著高于CA16阳性率(19%)(P<0.01);10株新乡EV71分离株的核苷酸及氨基酸差异分别为2.8%和0.9%,属于C4亚型的C4a簇;9株VP1区第170位氨基酸为A,1株为V;与近缘的C4a型代表株相比,新乡优势株的氨基酸变异一般发生在VP1第292位氨基酸(T→A);2011年新乡市共上报手足口临床诊断病例1118例,92%的发病年龄在3岁以下,发病高峰分别出现在4和12月份,提示一定要加强手足口病预防控制,寒冷天气尤其不能忽视。     

百色市2014年手足口病流行病学特征分析

目的分析百色市2014年手足口病流行特征,探讨该病的预防控制策略。方法采用描述流行病学方法对百色市2014年手足口病发病特征进行流行病学分析。结果 2014年百色市共报告手足口病44 520例,年发病率为1 258.05/10万,死亡17例,病死率为0.04%。病例报告有明显的季节性,4-6月为发病高峰;以0~5岁年龄组为主,占95.39%;男性发病率高于女性,男女发病比为1.44∶1;职业分布以散居儿童居多;病原学监测结果为EV71、Cox A16和其他肠道病毒混合感染;79.04%的重症病例(含死亡病例)由EV71感染所致。结论百色市手足口病流行情况严重,EV71仍是引起手足口病重症病例和死亡的主要病原体,今后仍需要采取综合性防治措施,开展健康教育,加强重症病人的筛查和救治,降低病死率。     

Hand foot and mouth disease due to enterovirus 71 in Malaysia

Hand foot and mouth disease is a febrile sickness complex characterized by cutaneous eruption (exanthem) on the palms and soles with simultaneous occurrence of muco-cutanous vesiculo-ulcerative lesions (enanthem) affecting the mouth.The illness is caused by a number of enteroviruses with coxsackievirus A16 and enterovirus 71 as the main causative agents.Human enterovirus 71 (EV71) belongs to the species Human enterovirus A under the genus Enterovirus within the family Picornaviridae.EV71 has been associated with an array of clinical diseases including hand foot and mouth disease (HFMD),aseptic meningitis,encephalitis and poliomyelitis-like acute flaccid paralysis.A large outbreak of HFMD due to highly neurovirulent EV71 emerged in Malaysia in 1997,and caused 41deaths amongst young children.In late 2000,a recurrence of an outbreak of HFMD occurred in Malaysia with S fatalities in peninsular Malaysia.Outbreak of HFMD due to EV71 recurred in 2003 with an unknown number of cases and mortalities.A similar outbreak of HFMD with 2 recorded deaths in young children occurred in peninsular Malaysia in late 2005 and this was followed by a larger outbreak in Sarawak (Malaysian Borneo) with 6 reported fatalities in the early part of 2006.The current on-going outbreak of HFMD started in peninsular Malaysia in epidemiological week 12 of 2010.As with other HFMD outbreaks in Malaysia,both EV71 and CA16 were the main aetiological viruses isolated.In similarity with the HFMD outbreak in 2005,the isolation of CA16 preceded the appearance of EV71.Based on the VP 1 gene nucleotide sequences,4 sub-genogroups of EV71 (C1,C2,B3 and B4) co-circulated and caused the outbreak of hand,foot and mouth disease in peninsular Malaysia in 1997.Two sub-genogroups (C1 and B4) were noted to cause the outbreak in 2000 in both peninsular Malaysia and Sarawak.EV71 of sub-genogroup B5 with smaller contribution from sub-genogroup C1 caused the outbreak in 2003.In the 2005 outbreak,besides the EV71 strains of sub-genogroup C1,EV71 strains belonging to sub-genogroup B5 were isolated but formed a cluster which was distinct from the EV71 strains from the sub-genogroup B5 isolated in 2003.The four EV71 strains isolated from clinical specimens of patients with hand,foot and mouth disease in the Sarawak outbreak in early 2006 also belonged to sub-genogroup B5.Phylogenetic analysis of the VP1 gene suggests that the EV71 strains causing the outbreak in Sarawak could have originated from peninsular Malaysia.Epidemiological and molecular data since 1997 show the recurrence of HFMD due to EV71 in Malaysia every 2 to 4 years.In each of the past outbreaks,more than one sub-genogroup of the virus co-circulate.     

Epidemiology and seroepidemiology of human enterovirus 71 among Thai populations

Background

Human enterovirus 71 (EV71) is an important pathogen caused large outbreaks in Asian-Pacific region with severe neurological complications and may lead to death in young children. Understanding of the etiological spectrum and epidemic changes of enterovirus and population’s immunity against EV71 are crucial for the implementation of future therapeutic and prophylactic intervention.

Results

A total of 1,182 patients who presented with the symptoms of hand foot and mouth disease (67.3%) or herpangina (HA) (16.7%) and admitted to the hospitals during 2008-2013 were tested for enterovirus using pan-enterovirus PCR targeting 5′-untranslated region and specific PCR for viral capsid protein 1 gene. Overall, 59.7% were pan-enterovirus positive comprising 9.1% EV71 and 31.2% coxsackievirus species A (CV-A) including 70.5% CV-A6, 27.6% CV-A16, 1.1% CV-A10, and 0.8% CV-A5. HFMD and HA occurred endemically during 2008-2011. The number of cases increased dramatically in June 2012 with the percentage of the recently emerged CV-A6 significantly rose to 28.4%. Co-circulation between different EV71 genotypes was observed during the outbreak. Total of 161 sera obtained from healthy individuals were tested for neutralizing antibodies (NAb) against EV71 subgenotype B5 (EV71-B5) using microneutralization assay. The seropositive rate of EV71-B5 was 65.8%. The age-adjusted seroprevalence for individuals was found to be lowest in children aged >6 months to 2 years (42.5%). The seropositive rate remained relatively low in preschool children aged > 2 years to 6 years (48.3%) and thereafter increased sharply to more than 80% in individuals aged > 6 years.

Conclusions

This study describes longitudinal data reflecting changing patterns of enterovirus prevalence over 6 years and demonstrates high seroprevalences of EV71-B5 NAb among Thai individuals. The rate of EV71 seropositive increased with age but without gender-specific significant difference. We identified that relative lower EV71 seropositive rate in early 2012 may demonstrate widely presented of EV71-B5 in the population before account for a large outbreak scale epidemic occurred in 2012 with due to a relatively high susceptibility of the younger population.     

Mutations in the non-structural protein region contribute to intra-genotypic evolution of enterovirus 71

Background

Clinical manifestations of enterovirus 71 (EV71) range from herpangina, hand-foot-and-mouth disease (HFMD), to severe neurological complications. Unlike the situation of switching genotypes seen in EV71 outbreaks during 1998–2008 in Taiwan, genotype B5 was responsible for two large outbreaks in 2008 and 2012, respectively. In China, by contrast, EV71 often persists as a single genotype in the population and causes frequent outbreaks. To investigate genetic changes in viral evolution, complete EV71 genome sequences were used to analyze the intra-genotypic evolution pattern in Taiwan, China, and the Netherlands.

Results

Genotype B5 was predominant in Taiwan’s 2008 outbreak and was re-emergent in 2012. EV71 strains from both outbreaks were phylogenetically segregated into two lineages containing fourteen non-synonymous substitutions predominantly in the non-structural protein coding region. In China, genotype C4 was first seen in 1998 and caused the latest large outbreak in 2008. Unlike shifting genotypes in Taiwan, genotype C4 persisted with progressive drift through time. A majority of non-synonymous mutations occurred in residues located in the non-structural coding region, showing annual increases. Interestingly, genotype B1/B2 in the Netherlands showed another stepwise evolution with dramatic EV71 activity increase in 1986. Phylogeny of the VP1 coding region in 1971–1986 exhibited similar lineage turnover with genotype C4 in China; however, phylogeny of the 3D-encoding region indicated separate lineage appearing after 1983, suggesting that the 3D-encoding region of genotype B2 was derived from an unidentified ancestor that contributed to intra-genotypic evolution in the Netherlands.

Conclusions

Unlike VP1 coding sequences long used for phylogenetic study of enteroviruses due to expected host immune escape, our study emphasizes a dominant role of non-synonymous mutations in non-structural protein regions that contribute to (re-)emergent genotypes in continuous stepwise evolution. Dozens of amino acid substitutions, especially in non-structural proteins, were identified via genetic changes driven through intra-genotypic evolution worldwide. These identified substitutions appeared to increase viral fitness in the population, affording valuable insights not only for viral evolution but also for prevention, control, and vaccine against EV71 infection.     

Co-Circulation and Genomic Recombination of Coxsackievirus A16 and Enterovirus 71 during a Large Outbreak of Hand,Foot, and Mouth Disease in Central China

A total of 1844 patients with hand, foot, and mouth disease (HFMD), most of them were children of age 1–3-year-old, in Central China were hospitalized from 2011 to 2012. Among them, 422 were infected with coxsackievirus A16 (CVA16), 334 were infected with enterovirus 71 (EV71), 38 were co-infected with EV71 and CVA16, and 35 were infected with other enteroviruses. Molecular epidemiology analysis revealed that EV71 and CVA16 were detected year-round, but EV71 circulated mainly in July and CVA16 circulated predominantly in November, and incidence of HFMD was reduced in January and February and increased in March. Clinical data showed that hyperglycemia and neurologic complications were significantly higher in EV71-infected patients, while upper respiratory tract infection and C-reactive protein were significantly higher in CVA16-associated patients. 124 EV71 and 80 CVA16 strains were isolated, among them 56 and 68 EV71 strains were C4a and C4b, while 25 and 55 CVA16 strains were B1a and B1b, respectively. Similarity plots and bootscan analyses based on entire genomic sequences revealed that the three C4a sub-genotype EV71 strains were recombinant with C4b sub-genotype EV71 in 2B–2C region, and the three CVA16 strains were recombinant with EV71 in 2A–2B region. Thus, CVA16 and EV71 were the major causative agents in a large HFMD outbreak in Central China. HFMD incidence was high for children among household contact and was detected year-round, but outbreak was seasonal dependent. CVA16 B1b and EV71 C4b reemerged and caused a large epidemic in China after a quiet period of many years. Moreover, EV71 and CVA16 were co-circulated during the outbreak, which may have contributed to the genomic recombination between the pathogens. It should gain more attention as there may be an upward trend in co-circulation of the two pathogens globally and the new role recombination plays in the emergence of new enterovirus variants.     

An overview of the evolution of enterovirus 71 and its clinical and public health significance

Since its discovery in 1969, enterovirus 71 (EV71) has been recognised as a frequent cause of epidemics of hand-foot-and-mouth disease (HFMD) associated with severe neurological sequelae in a small proportion of cases. There has been a significant increase in EV71 epidemic activity throughout the Asia-Pacific region since 1997. Recent HFMD epidemics in this region have been associated with a severe form of brainstem encephalitis associated with pulmonary oedema and high case-fatality rates. The emergence of large-scale epidemic activity in the Asia-Pacific region has been associated with the circulation of three genetic lineages that appear to be undergoing rapid evolutionary change. Two of these lineages (B3 and B4) have not been described previously and appear to have arisen from an endemic focus in equatorial Asia, which has served as a source of virus for HFMD epidemics in Malaysia, Singapore and Australia. The third lineage (C2) has previously been identified [Brown, B.A. et al. (1999) J. Virol. 73, 9969-9975] and was primarily responsible for the large HFMD epidemic in Taiwan during 1998. As EV71 appears not to be susceptible to newly developed antiviral agents and a vaccine is not currently available, control of EV71 epidemics through high-level surveillance and public health intervention needs to be maintained and extended throughout the Asia-Pacific region. Future research should focus on (1) understanding the molecular genetics of EV71 virulence, (2) identification of the receptor(s) for EV71, (3) development of antiviral agents to ameliorate the severity of neurological disease and (4) vaccine development to control epidemics. Following the successful experience of the poliomyelitis control programme, it may be possible to control EV71 epidemics if an effective live-attenuated vaccine is developed.     

Epidemiological Characteristics and Spatial-Temporal Clusters of Hand,Foot, and Mouth Disease in Zhejiang Province,China, 2008-2012

Hand, foot and mouth disease (HFMD) is one of the major public health concerns in China. Being the province with high incidence rates of HFMD, the epidemiological features and the spatial-temporal patterns of Zhejiang Province were still unknown. The objective of this study was to investigate the epidemiological characteristics and the high-incidence clusters, as well as explore some potential risk factors. The surveillance data of HFMD during 2008–2012 were collected from the communicable disease surveillance network system of Zhejiang Provincial Center for Disease Control and Prevention. The distributions of age, gender, occupation, season, region, pathogen’s serotype and disease severity were analyzed to describe the epidemiological features of HFMD in Zhejiang Province. Seroprevalence survey for human enterovirus 71 (EV71) in 549 healthy children of Zhejiang Province was also performed, as well as 27 seroprevalence publications between 1997 and 2015 were summarized. The spatial-temporal methods were performed to explore the clusters at county level. Furthermore, pathogens’ serotypes such as EV71 and coxsackievirus A16 (Cox A16) and meteorological factors were analyzed to explore the potential factors associated with the clusters. A total of 454,339 HFMD cases were reported in Zhejiang Province during 2008–2012, including 1688 (0.37%) severe cases. The annual average incidence rate was 172.98 per 100,000 (ranged from 72.61 to 270.04). The male-to-female ratio for mild cases was around 1.64:1, and up to 1.87:1 for severe cases. Of the total cases, children aged under three years old and under five years old accounted for almost 60% and 90%, respectively. Among all enteroviruses, the predominant serotype was EV71 (49.70%), followed by Cox A16 (26.05%) and other enteroviruses (24.24%) for mild cases. In severe cases, EV71 (82.85%) was the major causative agent. EV71 seroprevalence survey in healthy children confirmed that occult infection was common in children. Furthermore, literature summary for 26 seroprevalence studies during 1997–2015 confirmed that 0–5 years group showed lowest level of EV71 seroprevalence (29.1% on average) compared to the elder children (6–10 years group: 54.6%; 11–20 years group: 61.8%). Global positive spatial autocorrelation patterns (Moran’s Is>0.25, P<0.05) were discovered not only for mild cases but also for severe cases, and local positive spatial autocorrelation patterns were revealed for counties from the eastern coastal and southern regions. The retrospective space-time cluster analysis also confirmed these patterns. Risk factors analyses implied that more EV71 and less sunshine were associated with the clusters of HFMD in Zhejiang Province. Our study confirmed that Zhejiang Province was one of the highly epidemic provinces in China and that the epidemiological characteristics of HFMD were similar to other provinces. Occult infection in elder children and adults was one of the important reasons why most HFMD cases were children aged under-five. Combining the results of spatial autocorrelation analysis and the space-time cluster analysis, the major spatial-temporal clusters were from the eastern coastal and southern regions. The distribution of pathogens’ serotypes and the level of sunshine could be risk factors for, and serve as an early warning of, the outbreak of HFMD in Zhejiang Province.     

Recent Progress on Functional Genomics Research of Enterovirus 71

Enterovirus 71(EV71) is one of the main pathogens that causes hand-foot-and-mouth disease(HFMD). HFMD caused by EV71 infection is mostly self-limited; however, some infections can cause severe neurological diseases, such as aseptic meningitis, brain stem encephalitis, and even death. There are still no effective clinical drugs used for the prevention and treatment of HFMD. Studying EV71 protein function is essential for elucidating the EV71 replication process and developing anti-EV71 drugs and vaccines. In this review, we summarized the recent progress in the studies of EV71 noncoding regions(50 UTR and 30 UTR) and all structural and nonstructural proteins, especially the key motifs involving in viral infection, replication, and immune regulation. This review will promote our understanding of EV71 virus replication and pathogenesis, and will facilitate the development of novel drugs or vaccines to treat EV71.     

MA104 Cell line presents characteristics suitable for enterovirus A71 isolation and proliferation

Enterovirus A71 (EV‐A71), one of the most important causative agents of hand, foot and mouth disease (HFMD) in children, can lead to severe clinical outcomes, even death. However, the infection spectrum of EV‐A71 in different cell lines remains unknown. Therefore, in this study, the biological characteristics of EV‐A71 Subgroup C4 in different cell lines were investigated. To this end, the infectivity of EV‐A71Jinan1002 isolated from children with severe HFMD was assessed in 18 different host cell lines. It was found that the MA104 cell line displayed biological characteristics suitable for EV‐A71 Subgroup C4 strain isolation and proliferation; indeed, it was found that a broad spectrum of cell lines can be infected by EV‐A71Jinan1002. Among the screened cells, four cell lines (HEK293, RD, MA104 and Marc145) produced high 50% tissue culture infective dose (TCID₅₀) values calculated in viral proliferations (ranged from 10^7.6 to 10^7.8); the TCID₅₀ being negatively associated with the time to appearance of CPE. Proliferation curves demonstrated that EV‐A71Jinan1002 amplifies more efficiently in MA104, Hep‐2 and RD cells. Remarkably, the virus isolation rate was much higher in MA104 cells than in RD cells. Thus this study, to our knowledge, is for the first to explore the infection spectrum of EV‐A71 subgroup C4 in such a large number of different cell lines. Our data provide useful reference data for facilitating further study of EV‐A71.