Hexon-modified recombinant E1-deleted adenoviral vectors as bivalent vaccine carriers for Coxsackievirus A16 and Enterovirus 71

Hand, foot and mouth disease (HFMD) is a major public health concern in Asia; more efficient vaccines against HFMD are urgently required. Adenoviral (Ad) capsids have been used widely for the presentation of foreign antigens to induce specific immune responses in the host. Here, we describe a novel bivalent vaccine for HFMD based on the hexon-modified, E1-deleted chimpanzee adenovirus serotype 68 (AdC68). The novel vaccine candidate was generated by incorporating the neutralising epitope of Coxsackievirus A16 (CA16), PEP71, into hypervariable region 1 (HVR1), and a shortened neutralising epitope of Enterovirus 71 (EV71), sSP70, into HVR2 of the AdC68 hexon. In order to enhance the immunogenicity of EV71, VP1 of EV71 was cloned into the E1-region of the AdC68 vectors. The results demonstrated that these two epitopes were well presented on the virion surface and had high affinity towards specific antibodies, and VP1 of EV71 was also significantly expressed. In pre-clinical mouse models, the hexon-modified AdC68 elicited neutralising antibodies against both CA16 and EV71, which conferred protection to suckling mice against a lethal challenge of CA16 and EV71. In summary, this study demonstrates that the hexon-modified AdC68 may represent a promising bivalent vaccine carrier against EV71 and CA16 and an epitope-display platform for other pathogens.     

Hepatitis B virus core particles containing multiple epitopes confer protection against enterovirus 71 and coxsackievirus A16 infection in mice

Human enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the two major causative agents of hand-foot-and-mouth disease (HFMD). To investigate novel combined vaccines to prevent EV71 and CA16 infection, we constructed chimeric virus-like particles (tHBc/SPA or tHBc/SP VLPs) displaying conserved epitopes of EV71 (aa 208–222 of VP1 and aa 248–263 of VP2) and CA16 (aa271-285 of VP1) using a truncated hepatitis B virus core carrier (tHBc). Immunization with the chimeric VLPs induced epitope- or virus-specific IgG and neutralization antibodies against EV71 and CA16 in the mice. Compared with inactivated EV71, the chimeric VLPs induced significantly increased Th1 cytokine (IFN-γ, IL-2) production and decreased Th2 cytokine (IL-4, IL-10) responses. Neonatal mice born to dams immunized with the recombinant particles were completely protected from lethal EV71 and partially protected from CA16 infection. Co-expression of the conserved human MHC class I CD4+ T cell epitope (aa248-263 of VP2) did not improve the antiviral immunity of the chimeric VLP vaccine in mice. Our results demonstrate that experimental combination vaccines comprised of EV71 and CA16 epitopes induce both humoral and cellular immune responses and therefore support further preclinical and clinical development of a bivalent VLP vaccine targeting both CA16 and EV71.     

A combination vaccine comprising of inactivated enterovirus 71 and coxsackievirus A16 elicits balanced protective immunity against both viruses

Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the two major causative agents of hand, foot and mouth disease (HFMD), which is an infectious disease frequently occurring in children. A bivalent vaccine against both EV71 and CA16 is highly desirable. In the present study, we compare monovalent inactivated EV71, monovalent inactivated CA16, and a combination vaccine candidate comprising of both inactivated EV71 and CA16, for their immunogenicity and in vivo protective efficacy. The two monovalent vaccines were found to elicit serum antibodies that potently neutralized the homologous virus but had no or weak neutralization activity against the heterologous one; in contrast, the bivalent vaccine immunized sera efficiently neutralized both EV71 and CA16. More importantly, passive immunization with the bivalent vaccine protected mice against either EV71 or CA16 lethal infections, whereas the monovalent vaccines only prevented the homologous but not the heterologous challenges. Together, our results demonstrate that the experimental bivalent vaccine comprising of inactivated EV71 and CA16 induces a balanced protective immunity against both EV71 and CA16, and thus provide proof-of-concept for further development of multivalent vaccines for broad protection against HFMD.     

Chimeric enterovirus 71 virus-like particle displaying conserved coxsackievirus A16 epitopes elicits potent immune responses and protects mice against lethal EV71 and CA16 infection

Hand-foot-and-mouth disease (HFMD) is an infectious disease of infants and young children frequently caused by the enterovirus A species, mainly enterovirus 71 (EV71) and coxsackievirus A16 (CA16). In this study, we prepared the EV71 virus-like particle (EV71-VLP) and its chimeras using recombinant baculovirus (Bac-P1-3CD) co-expressing EV71 P1 (under polyhedrin promoter) and 3CD (under CMV-IE promoter) proteins in Sf9 cells. EV71-VLP chimera ChiEV71(1E)-VLP or ChiEV71(4E)-VLP displayed single CA16 PEP71 epitope in VP1 or four conserved CA16 neutralizing epitopes (PEP71 in VP1, aa136-150 in VP2, aa176-190 in VP3 and aa48-62 in VP4) by substitution of the corresponding regions of EV71 structure proteins, respectively. In mice, EV71-VLP and its chimeras elicited similar EV71-specific IgG and neutralizing antibody (NAb) titers compared to inactivated EV71. Expectedly, vaccination of ChiEV71(1E)-VLP or ChiEV71(4E)-VLP resulted in significantly increased CA16-specific IgG and NAb production and improved cross-protection against CA16 infection compared to EV71-VLP. Interestingly, the VLPs induced potent cellular immune responses and significantly decreased Th2 type (IL-4 and IL-10) cytokines secretion in the splenocytes of immunized mice compared to inactivated EV71 or inactivated CA16. Neonatal mice born to dams immunized with the chimeric VLPs or neonatal mice passively transferred with sera of immunized mice were completely protected from lethal EV71 challenge and partially protected from lethal CA16 infection. Our study provides a novel bivalent or multivalent vaccine strategy to prevent EV71 and related-enterovirus infections.     

A virus-like particle based bivalent vaccine confers dual protection against enterovirus 71 and coxsackievirus A16 infections in mice

Enterovirus 71(EV71) and coxsackievirus A16 (CA16) are responsible for hand, foot and mouth disease which has been prevalent in Asia-Pacific regions, causing significant morbidity and mortality in young children. Co-circulation of and co-infection by both viruses underscores the importance and urgency of developing vaccines against both viruses simultaneously. Here we report the immunogenicity and protective efficacy of a bivalent combination vaccine comprised of EV71 and CA16 virus-like particles (VLPs). We show that monovalent EV71- or CA16-VLPs-elicited serum antibodies exhibited potent neutralization effect on the homotypic virus but little or no effect on the heterotypic one, whereas the antisera against the bivalent vaccine formulation were able to efficiently neutralize both EV71 and CA16, indicating there is no immunological interference between the two antigens with respect to their ability to induce virus-specific neutralizing antibodies. Passive immunization with monovalent VLP vaccines protected mice against a homotypic virus challenge but not heterotypic infection. Surprisingly, antibody-dependent enhancement (ADE) of disease was observed in mice passively transferred with mono-specific anti-CA16 VLP sera and subsequently challenged with EV71. In contrast, the bivalent VLP vaccine conferred full protection against lethal challenge by either EV71 or CA16, thus eliminating the potential of ADE. Taken together, our results demonstrate for the first time that the bivalent VLP approach represents a safe and efficacious vaccine strategy for both EV71 and CA16.     

Intradermal injection of a fractional dose of an inactivated HFMD vaccine elicits similar protective immunity to intramuscular inoculation of a full dose of an Al(OH)3-adjuvanted vaccine

Enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16) are the two major causative agents of hand, foot and mouth disease (HFMD), which erupts in the Asia-Pacific regions. A bivalent vaccine against both EV71 and CVA16 is highly desirable. In the present study, on the bases that an experimental bivalent vaccine comprising of inactivated EV71 and CVA16 induces a balanced protective immunity against both EV71 and CVA16, we compare the immunogenicity and reactogenicity of one fourth of a full dose of an intradermal vaccine administered by needle-free liquid jet injector with a full dose of an intramuscular vaccine administered by needle-syringe in monkeys. The results suggest that intradermal injection of a fractional dose of an inactivated HFMD vaccine elicits similar immunogenicity and reactogenicity to intramuscular inoculation of a full dose of an Al(OH)₃-adjuvanted vaccine, regardless of whether monovalent or bivalent vaccines were used. Our results support the use of an intradermal bivalent vaccine strategy for HFMD vaccination in order to satisfy the requirements and reduce the costs.     

Efficacy of an inactivated bivalent vaccine for enterovirus 71 and coxsackievirus A16 in mice immunized intradermally

Human hand, foot, and mouth disease (HFMD), an important infectious disease in children, is caused mainly by enterovirus 71 (EV71) and coxsackievirus A16 (CA16). In this study, a bivalent inactivated EV71/CA16 vaccine is developed and evaluated in immunized BALB/c mice injected through the intradermal route. Q-RT-PCR detection of the mRNA of immune signal molecules in local epithelial tissues inoculated with the vaccine indicates activation of innate immunity, which includes upregulation of immune-related chemokines, interferons and CD molecules. Further, the finding that neutralizing antibodies and specific T cellular responses were elicited in adult mice after two immunizations with the vaccine at a 28-day interval, which endowed offspring mice to defend a viral challenge, suggests the successful induction of specific protective antiviral immunity. All these data suggest that immunization with this bivalent EV71/CA16 vaccine via the intradermal route elicits effective immunity against EV71 and CA16 infection.     

Identification and characterization of a cross-neutralization epitope of Enterovirus 71

Enterovirus 71 (EV71) infections in children manifest as exanthema and are most commonly known as hand-foot-and-mouth disease (HFMD). Because it can cause severe neurological complications like poliomyelitis, EV71 has now emerged as an important neurotropic virus in Asia. EV71 virus has been shown to consist of 3 (A, B and C) genotypes and many subgenotypes. Although EV71 vaccine development has recently yielded promising preclinical results, yet the correlation between the content of antigen(s) in vaccine candidates and the level of protective antibody responses is not established. The neutralization epitope(s) of EV71 antigens could be used as the surrogate biomarker of vaccine potency. Using peptide ELISA, antisera generated from animals immunized with formalin-inactivated EV71 virion vaccine formulated in alum, EV71-specific neutralizing monoclonal antibody (nMAb) and a panel of 153 overlapping synthetic peptides covering the entire sequences of VP1, VP2 and VP3 of EV71, we screened for immunodominant linear neutralization epitope(s). Synthetic peptide VP2-28, corresponding to residues 136-150 of VP2, was found to bind to and inhibit the binding to EV71 of nMAb MAB979 that was found to have cross-neutralizing activity against different genotypes of EV71 virus. In addition, VP2-28 was found to be recognized only by neutralizing antisera generated from rabbits immunized with the formalin-inactivated whole EV71 virion vaccine but not by antisera from immunized mice and rats. During the epitope mapping, a murine EV71 genotype- and strain-specific linear neutralization epitope VP1-43 was identified within residues 211-220 of VP1. Furthermore, based on sequence alignment and structure prediction analysis using poliovirus as the template for molecular modeling, the VP1-43 and VP2-28 epitopes were shown to run in parallel within 0.1 nm and form a rim of the canyon at the junction site of VP1 and VP2 in the viral capsid. In mouse, rat and rabbit immunogenicity studies, a dose-dependent relationship between the number of VP2-28 epitope units measured by a quantitative assay in vaccine preparations and the magnitude of neutralizing titers was demonstrated. VP2-28 has amino acid sequences that are highly conserved among EV71 genotypes, is not affected by formalin-treatment and long-term storage. Thus, VP2-28 could be used as the surrogate biomarker in the potency testing of candidate EV71 vaccines.     

A new EV71 VP3 epitope in norovirus P particle vector displays neutralizing activity and protection in vivo in mice

Enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16), as the main agents causing hand, foot and mouth disease (HFMD), have become a serious public health concern in the Asia-Pacific region. Recently, various neutralizing B cell epitopes of EV71 were identified as targets for promising vaccine candidates. Structural studies of Picornaviridae indicated that potent immunodominant epitopes typically lie in the hypervariable loop of capsid surfaces. However, cross-neutralizing antibodies and cross-protection between EV71 and CVA16 have not been observed. Therefore, we speculated that divergent sequences of the two viruses are key epitopes for inducing protective neutralizing responses. In this study, we selected 10 divergent epitope candidates based on alignment of the EV71 and CVA16 P1 amino acid sequences using the Multalin interface page, and these epitopes are conserved among all subgenotypes of EV71. Simultaneously, by utilizing the norovirus P particle as a novel vaccine delivery carrier, we identified the 71-6 epitope (amino acid 176–190 of VP3) as a conformational neutralizing epitope against EV71 in an in vitro micro-neutralization assay as well as an in vivo protection assay in mice. Altogether, these results indicated that the incorporation of the 71-6 epitope into the norovirus P domain can provide a promising candidate for an effective synthetic peptide-based vaccine against EV71.     

A novel combined vaccine based on monochimeric VLP co-displaying multiple conserved epitopes against enterovirus 71 and varicella-zoster virus

Chicken pox and hand, foot and mouth disease (HFMD) are two major infectious diseases that mainly affect infants and children, causing significant morbidity annually. Varicella-zoster virus (VZV) and enterovirus 71 (EV71), respectively, are the principal epidemic pathogens causing these two diseases. To investigate the possibility of developing a novel combined vaccine to prevent chicken pox and HFMD, we constructed three chimeric virus-like particles (VLPs) (termed HBc-V/1/2, HBc-2/V/1 and HBc-1/2/V) based on the hepatitis B core antigen (HBc) carrier that display epitopes derived from VZV-gE, EV71-VP1, and EV71-VP2 in a varied tandem manner. The chimeric HBc can self-assemble into VLPs with these three epitopes displayed on the surface of particles. Epitope-specific antibody characterization suggested that HBc-V/1/2 elicits a balanced antibody response toward these three epitopes, and no immune interference was observed between the three epitopes. Importantly, the anti-HBc-V/1/2 sera could simultaneously neutralize VZV and EV71 and cross-neutralize coxsackievirus A16 (CVA16), another major pathogen causing HFMD. Moreover, the anti-HBc-V/1/2 sera protected neonatal mice from lethal challenge of EV71 and CVA16. Collectively, our study not only demonstrated that HBc-V/1/2 is a promising candidate combined vaccine for HFMD and Chicken pox but also provides a novel strategy for the design of combined vaccines.     

Study of integrated protective immunity induced in rhesus macaques by the intradermal administration of a bivalent EV71-CA16 inactivated vaccine

Enterovirus type 71 (EV71) and coxsackievirus A 16 (CA16) are recognized as the major pathogens responsible for human hand-foot-mouth disease. To develop a bivalent EV71-CA16 vaccine, rhesus macaques immunized with two doses of this vaccine via the intradermal route were challenged with EV71 or CA16, and their clinical symptoms, viral shedding, neutralizing antibodies, IFN-γ-specific ELISpots, and tissue viral load were examined longitudinally. Specific immunity against EV71 and CA16 was observed in the macaques, which exhibited controlled proliferation of the EV71 and CA16 viruses and upregulated expression of immune-related genes compared with the controls. Furthermore, broad protection against EV71 and CA16 challenge without immunopathological effects was observed in all the immunized macaques. These studies suggest that the bivalent EV71-CA16 inactivated vaccine was effective against wild-type EV71 or CA16 viral challenge in rhesus macaques.     

Prospect and challenges for the development of multivalent vaccines against hand,foot and mouth diseases

Enterovirus 71 (EV71), an emerging neurotropic virus and coxsackieviruses (CV) are the major causative agents of hand, foot and mouth diseases (HFMD). These viruses have become a serious public health threat in the Asia Pacific region. Formalin-inactivated EV71 (FI-EV71) vaccines have been developed, evaluated in human clinical trials and were found to elicit full protection against EV71. Their failure to prevent CVA16 infections could compromise the acceptability of monovalent EV71 vaccines. Bivalent FI-EV71/FI-CVA16 vaccines have been found to elicit strong neutralizing antibody responses against both viruses in animal models but did not protect against CVA6 and CVA10 viral infections in cell culture neutralization assay. In this review, we discuss the critical bottlenecks in the development of multivalent HFMD vaccines, including the selection of vaccine strains, animal models to assess vaccine potency, the definition of end-points for efficacy trials, and the need for improved manufacturing processes to produce affordable vaccines.     

安徽省肠道病毒71型VP1区基因分析

目的阐述引起安徽省2008年手足口病（hand,foot and mouth disease,HFMD）流行的肠道病毒71型（enterovirus71,EV71）基因特征。方法采集HFMD暴发初期患者标本,进行病毒分离、培养,通过逆转录-聚合酶链反应（RT-PCR）鉴定上述培养物。扩增病毒株及核酸样本的VP1编码区全基因,并进行序列测定和分析。结果暴发初期分离出3份病毒株,经中和试验及RT-PCR证实为EV71。根据VP1全基因序列与EV71基因型、亚型参考株构建亲缘性关系树,17份测序结果与C4亚型聚为一簇,与A、B、C1、C2、C3、C4基因型别（亚型）的核苷酸的同源性分别为：82.0%-83.0%、84.3%-85.4%、89.7%-91.1%、89.1%-90.7%、88.3%-89.8%、93.0%-94.6%;氨基酸的同源性分别为：93.9%-95.2%、96.6%-97.6%、97.9%-98.6%、98.6%-99.3%、98.3%-98.9%、98.6%-99.6%;簇内比较显示,1株2006年的EV71毒株与另16份2008年样本在C4亚型内又分属两个亚簇,核苷酸、氨基酸的同源性分别为：96.2%-96.9%、98.3%-99.3%。结论引起安徽省2008年HFMD的EV71为C4亚型,与2006年分离的1份毒株有差异,提示安徽省存在C4亚型的不同分支。     

天津市手足口病分子流行病学分析

目的分析天津市手足口病病原学分布及肠道病毒71型(EV71)分子流行病学特点。方法采集天津市各医院2008—2010年手足口病住院患者粪便标本2 377份,采用逆转录-聚合酶链反应(RT-PCR)检测肠道病毒核酸;选取部分EV71阳性标本分离病毒,采用RT-PCR扩增其VP1基因,进行序列测定和同源性分析,建立系统发生树。结果 2 377份手足口病粪便标本中,肠道病毒总阳性率为70.72%(1 681/2 377),其中EV71占48.30%,CV-A16占37.36%,其他EV占14.34%;31株EV71分离株与C4亚型的C4a分支参比株具有最高核苷酸序列同源性,同源性为95.7%～99.2%,在系统发生树上均归属于C4a分支。结论天津市2008—2010年手足口病主要病原体为EV71,其流行株为C4亚型中的C4a病毒株。     

Establishing China's national standards of antigen content and neutralizing antibody responses for evaluation of enterovirus 71 (EV71) vaccines

Enterovirus 71 (EV71) is a highly infectious agent that causes hand-foot-mouth disease (HFMD) in humans. Effective vaccination against EV71 infection is critically important, given the recent outbreak of HFMD in the Asia-Pacific region, where it has shown significant mortality and morbidity. There is currently no approved anti-viral therapy available to treat the disease. While several vaccine manufacturers are actively developing EV71 vaccines, there are no international reference standards available to conduct quality control on EV71 vaccines or to assess the effectiveness of EV71 vaccines in immunized populations. In the current report, antigen reference standard based on the C4 subtype of the EV71 vaccine strain was developed. In addition, neutralizing antibody (NTAb) reference panels were analyzed and standards with various neutralizing titers were selected. These reference antigens were used to calibrate vaccine samples from several producers and found that five EV71 antigens and the national reference standards showed good linearity and parallelism. Moreover, mice immunized with various vaccines at doses standardized by these national references showed comparable NTAb responses. Finally, the national NTAb reference panels were found to effectively reduce assay discrepancy between different labs. Taken together, these national reference standards are highly valuable for the standardization and evaluation of EV71 vaccines.     

Cross-reactive neutralizing antibody epitopes against Enterovirus 71 identified by an in silico approach

Currently, infections of hand, foot and mouth disease (HFMD) due to Human Enterovirus 71 (EV71) cannot be prevented or treated, as there are no suitable vaccines or antiviral drugs. This study aimed to identify potential vaccine candidates for EV71 using in silico analysis of its viral capsid proteins. A combined in silico approach utilizing computational hidden Markov model (HMM), propensity scale algorithm, and artificial learning, identified three 15-mer structurally conserved B-cell epitope candidates lying within the EV71 capsid proteins. Peptide vaccine candidates incorporating a target B-cell epitope and a promiscuous T-cell epitope from the related polio virus were synthesized using solid-phase Fmoc chemistry. Inbred BALB/C mice which were inoculated with two 10 μg doses of the synthetic peptide, generated anti-peptide antibodies. Purified IgG isolated from pooled sera of the inoculated mice neutralized EV71 infections in vitro. Furthermore, these neutralizing antibodies were cross-reactive against other members of the Picornaviridae family, demonstrating greater than 50% virus neutralization. This indicates that the current approach is promising for the development of synthetic peptide-based vaccine candidates against Picornaviridae. Development of effective vaccines is of paramount importance in managing the disease in the Asia Pacific regions where this virus is endemic and has significant social, economic and public health ramifications.     

2010年合肥儿童手足口病病例肠道病毒血清基因型分析

目的:对合肥地区2010年5~7月儿童手足口病流行期间的手足口病患儿进行病原学调查。方法:采集手足口病患儿的疱疹液、粪便、咽拭子进行病毒分离;分离的病毒接种非洲绿猴肾细胞(Vero)后待细胞病变(CPE)达到++++以上后提取RNA。分别用EV71和CA16的VP1基因的特异性引物进行RT-PCR鉴定,并根据血清型不同比较其临床特征。结果:77例患儿采集的标本中65例分离到病毒;经RT-PCR检测发现其中47例CA16阳性,18例为EV71,比例为2.6∶1。CA16感染和EV71感染在患者的年龄大小、症状轻重等方面无显著统计学差异。结论:手足口病患儿检测到的主要病原是CA16和EV71,两者感染对临床的影响无显著差异。     

Vesicular stomatitis virus-based vaccines expressing EV71 virus-like particles elicit strong immune responses and protect newborn mice from lethal challenges

Enterovirus 71 (EV71) belonging to the Picornaviridae family is considered the most frequently detected causative agent in hand-foot-and-mouth disease (HFMD) and is a serious threat to public health in the Asia-Pacific region. There are currently no approved vaccines or effective drugs for EV71. In this study, using recombinant vesicular stomatitis virus (rVSV) expressing viral VP1 protein (mVP1) of EV71 as a control, we generated two types of rVSVs that can form EV71 virus-like particles (VLPs). First, we co-infected two rVSVs singly expressing P1 (mP1) and 3CD (m3CD) of EV71. Second, we inserted P1 and 3CD into one VSV backbone to generate an rVSV expressing P1 and 3CD together (mP1-3CD). When P1 and 3CD were expressed in the cells either co-infected with mP1 and m3CD (mP1/m3CD) or infected with mP1-3CD, P1 was cleaved by 3CD and produced VP1, VP3, and VP0 to form VLPs. Furthermore, mice immunized with mP1/m3CD or mP1-3CD showed higher humoral and cellular immunity responses than mice immunized with mVP1. Finally, the rVSVs expressing the EV71 proteins were evaluated in mice to determine their potential to protect against a lethal EV71 virus challenge, and among all the rVSVs, the mP1-3CD was shown to be the most promising vaccine candidate for EV71 protection.     

2013 - 2017年无锡市手足口病流行病和病原学特征分析

目的 了解无锡市2013 - 2017年手足口病（HFMD）流行病学及病原学变化特征,为本地区HFMD防控提供科学依据。方法 利用2013 - 2017年疾病监测信息系统报告的HFMD病例进行描述性流行病学分析。同时收集无锡市哨点医院HFMD病例的粪便样本,采用肠道病毒通用（EV）、肠道病毒71型（EV71）和柯萨基病毒A组16型（CA16）荧光定量检测试剂盒进行核酸检测和测序分析。结果 无锡市2013 - 2017年共报告HFMD 82 132例,年均发病率249.32/10万。病例报告以1～3岁发病率最高,且以散童（53.72%）为主。全年有5 - 7月和11 - 12月2个发病高峰,重症发生集中在7 - 8月。2013 - 2017年病原学监测结果显示,普通病例以EV71（46.08%）和CA16（35.78%）为主,重症病例以EV71（86.45%）为主（P＜0.001）。2012 - 2016年其他肠道病毒以CB5为主,占72.50%;2017年其它肠道病毒以CA6为主,占90.00%。结论 无锡市HFMD的发生存在周期性和季节性,呈现每隔1～2年出现1次流行高峰的特点;居住在城乡结合部地区的1～3岁儿童是HFMD的重点防控人群;2017年其他肠道病毒优势株由CB5转为CA6,CA6可能成为继CA16、EV71的另一个其他肠道病毒优势株。     

环介导等温扩增法快速检测手足口病病原体

目的：建立逆转录（RT）-环介导等温扩增方法（LAMP）,以快速检测手足口病最重要的两种病原体：肠道病毒71型（EV71）和柯萨奇病毒A组16型（CA16）。方法：收集手足口病患儿咽拭子标本93份,针对EV71和CA16病毒的VP1基因特异性序列8个区域各设计6条LAMP引物,分别于63℃（EV71）、65℃（CA16A）扩增1 h,日光下观察结果,与实时荧光定量PCR比较检测特异性和敏感性。结果：EV71、CA16的LAMP最低检测限均为500拷贝/管,与对照病毒无交叉反应。93份标本中,RT-PCR方法检测显示EV71阳性44例,CA16阳性36例;RT-LAMP方法检测显示EV71阳性46例,CA16阳性36例,两种方法间比较差异均无统计学意义（P〉0.05）。结论：应用RT-LAMP检测手足口病病原体EV71、CA16快速、灵敏、经济、特异性高,适合在基层医疗机构推广应用。