Analysis of the vaccination status of enterovirus type 71 inactivated vaccine in China from 2017 to 2021 / 中华流行病学杂志

Objective: To understand the vaccination status of enterovirus type 71 (EV71) inactivated vaccines in China from 2017 to 2021 and provide evidence for making policy on immunization strategy against hand, foot and mouth disease (HFMD). Methods: Using the reported dose number of EV71 vaccination and birth cohort population data collected by the China immunizaiton program information system to estimate the cumulative coverage of EV71 vaccine by the end of 2021 among the birth cohorts since 2012 at national, provincial, and prefecture levels, and analyze the correlation between the vaccination coverage and the potential influencing factors. Results: As of 2021, the estimated cumulative vaccination coverage of the EV71 vaccine was 24.96% in birth cohorts since 2012. The cumulative vaccination coverage was between 3.09% and 56.59% in different provinces, between 0 and 88.17% in different prefectures. There was a statistically significant correlation between vaccination coverage in different regions and the region's previous HFMD prevalence and disposable income per capita. Conclusions: Since 2017, the EV71 vaccines have been widely used nationwide, but the coverage of EV71 vaccination varies greatly among regions. Vaccination coverage is higher in relatively developed regions, and the intensity of previous epidemic of HFMD may have a certain impact on the acceptance of the vaccine and the pattern of immunization service. The impact of EV71 vaccination on the epidemic of HFMD requires further studies.

Boletín epidemiológico 12 - 2022. Semana epidemiológica del 20 al 26 de marzo del 2022 / Epidemiological bulletin 12 - 2022. Epidemiological week from March 20 to 26, 2022

La enfermedad de mano, pie y boca (EMPB) es una patología infecciosa pediátrica común, causada por el enterovirus (EV) de la familia Picornaviridae, incluidos EV-A71 y los virus Coxsackie (CV) CV-A2, CV-A6, CV-A10 y CV- A16. Aunque generalmente es autolimitada, puede provocar graves complicaciones asociadas con una infección neurológica (encefalitis, meningitis) o una enfermedad respiratoria fatal. La mayoría de los casos presentan fiebre, erupciones cutáneas en manos y pies y vesículas o úlceras en la mucosa bucal. Los casos afectan principalmente a niños entre los 0 a 5 años, pero también puede afectar a niños mayores y adultos

Epidemiological characteristics of hand, foot and mouth disease among people aged 6 and over in Beijing, 2011-2020 / 中华流行病学杂志

Objective: To analyze the epidemiological characteristics of hand, foot and mouth disease (HFMD) among people ≥6 years old in Beijing from 2011 to 2020. Methods: The incidence data of HFMD cases from 2011 to 2020 were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and the etiological surveillance of HFMD in 29 sentinel hospitals from 16 districts of Beijing. Descriptive epidemiological methods were used to analyze the distributions, pathogen constituents, and changes of HFMD cases in Beijing people ≥6 years old. Results: From 2011 to 2020, a total of 38 183 cases of HFMD were reported among people ≥6 years old in Beijing, of which 46 (0.12%) cases were severe. The average annual reported incidence was 19.04/100 000. The ratio of males to females were 1.37∶1(22 064∶16 119). The proportion of HFMD in people ≥6 years old increased from 7.56%(2 606/34 488) in 2011 to 24.54% (546/2 225) in 2020. The average incidence of HFMD was higher in Shunyi district, Yanqing district, and Tongzhou district than in other districts in Beijing. The positive rate of enterovirus in sentinel surveillance was 66.78% (1 976/2 959), the proportion of enterovirus group A 71 (EV-A71) was 45.29% (101/223) in 2014, no EV-A71 positive was detected in 2020, and the proportion of Coxsackievirus A 6 (CV-A6) increased from 15.11% (34/225) in 2016 to 81.08% (60/74) in 2020. Conclusions: From 2011 to 2020, the proportion of cases with HFMD in people ≥6 years old in Beijing increased yearly, and the proportion of EV-A71 positive patients decreased basically. Since 2016, CV-A6 has gradually become the dominant pathogen. More attention should be paid to the epidemic situation and dynamic pathogen changes of hand foot mouth disease in people ≥6 years old.

Etiology and epidemiology of hand, foot and mouth disease in China / 中华流行病学杂志

Hand, foot and mouth disease (HFMD) has been widespread in the world, and caused fever, rashes and other clinical symptoms of children, and sometimes inducing respiratory failure, brainstem encephalitis, and other complications, even death. The disease is mainly caused by enterovirus 71 (EV-A71) and coxsackievirus 16 (CV-A16). Since 2013, the proportion of HFMD cases caused by other enteroriruses has gradually increased, causing severe and even fatal cases. This paper summarizes the research progress in the epidemiological and etiological characteristics of HFMD in China since 2008.

Effect of Pien Tze Huang against EV71 / 中国中药杂志

This study aims to investigate the inhibitory effect of Pien Tze Huang(PZH) on enterovirus 71(EV71). To be speci-fic, chemiluminescence method was adopted to evaluate the toxicity of PZH to African green monkey kidney(Vero) cells and human rhabdomyosarcoma(RD) cells, and cytopathic effect(CPE) method to assess the inhibition on EV71-GFP reporter virus and EV71 C4 wild-type virus. The results showed that PZH had low cytotoxicity to Vero cells and RD cells, with the half-maximal cytotoxic concentration(CC_(50)) of about 0.691 3-0.879 2 mg·mL~(-1) for the two. In addition, PZH can effectively inhibit the replication of EV71 within the non-cytotoxic concentration range, and dose-dependently alleviate the cytopathic changes caused by virus infection, with the half-maximal effective concentration(EC_(50)) of 0.009 2-0.106 3 mg·mL~(-1). On the basis of the above results, the green fluorescent protein(GFP), indirect immunofluorescence assay(IFA), and median tissue culture infective dose(TCID_(50)) were employed to assess and verify the anti-EV71-GFP and anti-EV71 C4 activity of PZH. The results demonstrated that PZH can dose-dependently lower the expression of GFP by EV71-GFP and structural protein VP-1 by EV71 C4 and decrease the production of progeny infectious viruses. The EC_(50) of PZH for EV71-GFP and EV71 C4 was about 0.006 0-0.006 2 mg·mL~(-1) and 0.006 6-0.025 6 mg·mL~(-1), respectively. This study suggested that PZH may exert antiviral activity by acting on EV71 and interfering with the expression of VP-1. At the moment, there is still a lack of specific anti-EV71 drugs. This study proposed a new idea for the symptomatic treatment of EV71 infections such as hand-foot-mouth disease and verified an effective drug for the treatment of EV71 infections.

Genotipificación del virus de la enfermedad mano-pie-boca atípica en un hospital pediátrico de la Ciudad de Buenos Aires, Argentina / Atypical hand-foot-mouth disease virus genotyping in a pediatric hospital in Buenos Aires city, Argentin

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.

Enterovirus 71 can induce autophagy and apoptosis of THP-1 macrophages / 南方医科大学学报

OBJECTIVE@#To investigate enterovirus 71 (EV71)-induced of autophagy, apoptosis and the related signaling pathways in THP-1 macrophages.@*METHODS@#THP-1 macrophages were infected with EV71 at the multiplicity of infection (MOI) of 0.1 for 2, 8 or 16 h, and the cell proliferation and toxicity were analyzed using CCK-8 kit. The intracellular viral nucleic acid in THP-1 macrophages were detected by fluorescence quantitative PCR, and the ultrastructural changes of the cells were observed using transmission electron microscopy. Cell apoptosis induced by EV71 infection was detected using Hoechst 33342 staining and AnnexinV/PI double staining. Western blotting was performed for analysis of changes in autophagy and apoptosis of the cells and in the expressions of the related proteins. The effect of EV71 infection on apoptosis of THP-1 macrophages incubated with 3-MA and Ac-DEVD-CHO inhibitor for 2 h was assessed using Western blotting.@*RESULTS@#EV71 infection significantly lowered the cell survival rate of THP-1 macrophages at 2, 8 h and 16 h after the infection ( < 0.05). The total copy number of viral nucleic acid in THP-1 macrophages incubated with EV71 increased significantly and progressively over time ( < 0.01). Intracellular autophagosomes and virions could be seen in EV71-infected THP-1 macrophages. The total apoptotic rate of the infected cell also increased significantly over time ( < 0.01). EV71 infection significantly increased LC3 conversion (LC3-Ⅱ/ LC3-I) and the expression of cleaved caspase 3 protein and decreased the protein expressions of p62, Bcl-2 and caspase-3 ( < 0.01) without causing obvious changes in cleaved caspase-8 (>0.05). 3-MA significantly inhibited the EV71-induced autophagy of THP-1 macrophages and reduced LC3 conversion (LC3-Ⅱ/LC3-I) and p62 protein expression at 8 h after EV71 infection ( < 0.01). Compared with DMSO, Ac-DEVD-CHO significantly inhibited EV71-induced apoptosis of THP-1 macrophages (15.5% 7.7%, < 0.01).@*CONCLUSIONS@#EV71 not only can infect and replicate in THP-1 macrophages, but also induces autophagy and cell apoptosis possibly by activating LC3/p62 autophagy pathway and caspase apoptosis pathway.

RT-nPCR Assays for Amplification and Sequencing of VP1 Genes in Human Enterovirus A-D from Clinical Specimens / 生物医学与环境科学（英文）

Objective@#To develop RT-nPCR assays for amplifying partial and complete VP1 genes of human enteroviruses (HEVs) from clinical samples and to contribute to etiological surveillance of HEV-related diseases.@*Methods@#A panel of RT-nPCR assays, consisting of published combined primer pairs for VP1 genes of HEV A-C and in-house designed primers for HEV-D, was established in this study. The sensitivity of each RT-nPCR assay was evaluated with serially diluted virus stocks of five serotypes expressed as CCID @*Results@#The sensitivity of RT-nPCR assays for amplifying partial VP1 gene of HEVs was 0.1 CCID @*Conclusion@#This RT-nPCR system is capable of amplifying the partial and complete VP1 gene of HEV A-D, providing rapid, sensitive, and reliable options for molecular typing and molecular epidemiology of HEVs in clinical specimens.

Clinical effect of carvedilol in treatment of children with severe hand-foot-mouth disease caused by enterovirus 71 infection / 中国当代儿科杂志

OBJECTIVE@#To study the clinical effect of carvedilol in the treatment of children with severe hand-foot-mouth disease (HFMD) caused by enterovirus 71 (EV71) infection.@*METHODS@#A retrospective analysis was performed for the clinical data of 86 children with severe HFMD caused by EV71 infection who were admitted to the hospital from April 2016 to August 2017. According to whether carvedilol was used, the children were divided into conventional treatment group with 51 children and carvedilol treatment group with 35 children. A total of 56 healthy children who underwent physical examination at the outpatient service during the same period were enrolled as the control group. The two treatment groups were compared in terms of clinical features and levels of catecholamines (norepinephrine, adrenaline and dopamine), and the levels of catecholamines were compared between these two treatment groups and the control group.@*RESULTS@#Before treatment, the conventional treatment group and the carvedilol treatment group had significantly higher levels of norepinephrine and adrenaline than the control group (P<0.05). After treatment, both the conventional treatment group and the carvedilol treatment group had significant reductions in norepinephrine, adrenaline, blood glucose, systolic pressure, diastolic pressure, heart rate, body temperature and leukocyte count (P<0.05). Compared with the conventional treatment group, the carvedilol treatment group had significantly lower dopamine level, blood glucose, heart rate and respiratory rate after treatment (P<0.05).@*CONCLUSIONS@#Changes in norepinephrine and adrenaline might be involved in the pathogenesis of severe HFMD caused by EV71 infection. Carvedilol, in addition to the conventional treatment, can improve respiration, heart rate and blood glucose in children with severe HFMD caused by EV71 infection.

Association of interleukin-10 gene polymorphism with enterovirus 71 infection in children / 中国当代儿科杂志

OBJECTIVE@#To study the association of interleukin-10 (IL-10) -1082A/G, -819C/T, and -592C/A polymorphisms with IL-10 level and the severity of enterovirus 71 (EV71) infection in children.@*METHODS@#A total of 137 children with hand-foot-mouth disease due to EV71 infection were enrolled as EV71 infection group, which was further divided into mild group with 91 children and severe group with 46 children, and 122 healthy children who underwent physical examination were enrolled as healthy control group. Related clinical data were collected. ELISA was used to measure the serum level of IL-10, and polymerase chain reaction-restriction fragment length polymorphism was used to analyze IL-10 -1082A/G, -819C/T and -592C/A polymorphisms.@*RESULTS@#Compared with the healthy control group, the children with EV71 infection had significantly higher frequency of -1082 AA genotype and A allele (P0.05). The severe group had a significantly higher serum level of IL-10 than the mild group and the healthy control group. IL-10 -1082 AA genotype, -819 TT genotype, and -592 AA genotype were associated with the low expression of IL-10 (P0.05).@*CONCLUSIONS@#IL-10 gene polymorphisms are associated with IL-10 expression and the severity of EV71 infection in children.

Hospitalization burden of hand, foot and mouth disease in Anhua county of Hunan province, 2013-2016 / 中华流行病学杂志

Objective: To estimate the serotype and age-specific hospitalization burden associated with hand, foot and mouth disease (HFMD) in Anhua county of Hunan province, between October 2013 and September 2016. Methods: We collected hospitalization records of HFMD patients from 6 virological surveillance hospitals, and reimbursement records through new rural cooperative medical system from 23 township health centers to estimate the age-specific hospitalization burden of HFMD in Anhua. Combined with the results of virological surveillance, the serotype-specific hospitalization burden of HFMD in Anhua, was estimated. Results: During the three years, it was estimated that 3 541 clinical diagnosed HFMD cases, including 3 146 laboratory-confirmed HFMD cases, were hospitalized in Anhua, but only one was diaguosed as being severe. The estimated average hospitalization rate was 723/100 000(95%CI: 699/100 000-747/100 000) for clinical diagnosed HFMD and 642/100 000 (95%CI: 620/100 000-665/100 000) for laboratory-confirmed HFMD between October 2013 and September 2016. The cases caused by Cox A16 (208/100 000) and Cox A6 (202/100 000) had higher hospitalization rates compared with the cases caused by EV71 (130/100 000), Cox A10 (38/100 000) and other enterovirus (64/100 000), and the difference was statistically significant (P<0.001). HFMD-associated hospitalization rates peaked in children aged 1 year (3 845/100 000), and then decreased with age. Compared with the hospitalized HFMD caused by EV71 and Cox A16, Cox A6-associated hospitalizations mainly occurred in younger age groups (P<0.001). Conclusion: Our study revealed a substantial hospitalization burden associated with mild HFMD caused by EV71, Cox A16, Cox A6 and Cox A10, especially in young children, in Anhua.

Trend of epidemics and variation of pathogens of hand, foot and mouth disease in China: a dynamic series analysis, 2008-2017 / 中华流行病学杂志

Objective: To understand the trend of epidemics and variation of pathogens on hand, foot and mouth diseases (HFMD) in China for setting up appropriate intervention measures. Methods: Data related to reported cases and outbreaks of HFMD from the National Notifiable Disease Surveillance Reporting System of China, 2008 to 2017, was collected and analyzed. Based on the geographical location and types of climate, the total 31 provinces, autonomous regions and municipalities in the mainland of China, were divided into seven regions: north-west, north, mid-north, east, mid-south, south, and south-west regions, with epidemic trends and variation of pathogens analyzed. The average speed of growth on the dynamic series from 2008 to 2017 was calculated, using the Geometric Average method. Results: The overall reported incidence rate of HFMD during 2008-2017 was 134.59 per 100 000 population with an average increase of 15.92%. The proportion of severe cases was 0.84%, with 9.56% increase. The reported mortality rate of HFMD was 0.03/100 000, with an average decrease of 3.49%. The case fatality rate was 0.02% and with a decrease of 16.86%. A total of 6 000 outbreaks were reported during the decade. Except for 1.09% decrease on the incidence rate in the north region, all the other regions showed an increase on the morbidity rates, with the highest as25.20% in the south region. Mortality rates showed 27.53% and 0.60% increases in both the south-west and mid-north regions, respectively. Mortality rates in the other regions all showed a decreasing trend. In terms of case fatality rate, it increased 4.15% in the south-west region while all decreased in the other regions. Two higher age-special morbidity rates appeared in the 1 year olds as 3 184.19/100 000 and in the 2 year olds as 2 547.47/100 000, with the most increase seen in both 0 year (26.08%) and 1 year age groups (23.35%). High age-specific mortality rates were noticed in both the 1-year group as 0.86/100 000 and the 2-year group as 0.54/100 000, however with reductions as 1.21% and 10.70% respectively. As for the case fatalities, the 0 year olds and 1 year olds accounted for 0.039% and 0.027% but both of them had decreased by 19.12% and 19.91%, respectively. Case fatality rates decreased by 16.93% and 16.75%, in males and females. Proportions of EV71 and Cox A16 decreased by 4.28% and 3.07%, but the proportion of other entero-viruses increased by 16.07%. EV71 was responsible for the high frequency of epidemics in both mid-north and the mid-south regions. However, in other five regions, other strains of EV's were responsible for the epidemics. Conclusions: The characteristics of HFMD in China showed that the morbidity of HFMD and proportion of severe cases were both in increasing trends but both the mortality and case fatality of HFMD were decreasing. Children younger than 3 years old showed both high infection and death rates for HFMD. Epidemics caused by other enteroviruses of non-EV71 and non-Cox A16 were seen more. Variance and pathogens related to the epidemic cycles appeared different in the seven regions.

Efficient Humoral and Cellular Immune Responses Induced by a Chimeric Virus-like Particle Displaying the Epitope of EV71 without Adjuvant / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To eliminate the side effects of aluminum adjuvant and His-tag, we constructed chimeric VLPs displaying the epitope of EV71 (SP70) without His-tagged. Then evaluating whether the VLPs could efficiently evoke not only humoral but also cellular immune responses against EV71 without adjuvant.</p><p><b>METHODS</b>The fusion protein was constructed by inserting SP70 into the MIR of truncated HBcAg sequence, expressed in E. Coli, and purified through ion exchange chromatography and density gradient centrifugation. Mice were immunized with the VLPs and sera were collected afterwards. The specific antibody titers, IgG subtypes and neutralizing efficacy were detected by ELISA, neutralization assay, and EV71 lethal challenge. IFN-γ and IL-4 secreted by splenocytes were tested by ELISPOT assay.</p><p><b>RESULTS</b>HBc-SP70 proteins can self-assemble into empty VLPs. After immunization with HBc-SP70 VLPs, the detectable anti-EV71 antibodies were effective in neutralizing EV71 and protected newborn mice from EV71 lethal challenge. There was no significant difference for the immune efficacy whether the aluminum adjuvant was added or not. The specific IgG subtypes were mainly IgG1 and IgG2b and splenocytes from the mice immunized produced high levels of IFN-γ and IL-4.</p><p><b>CONCLUSION</b>The fusion proteins without His-tagged was expressed and purified as soluble chimeric HBc-SP70 VLPs without renaturation. In the absence of adjuvant, they were efficient to elicit high levels of Th1/Th2 mixed immune response as well as assisted by aluminum adjuvant. Furthermore, the chimeric VLPs have potential to prevent HBV and EV71 infection simultaneously.</p>

Epidemiological characteristics of Coxsackie virus A16 caused hand foot and mouth disease cases in Guangdong province, 2012-2016 / 中华流行病学杂志

Objective: To analyze the epidemiological characteristics of hand foot and mouth disease (HFMD) cases caused by Coxsackie virus A16 (Cox A16) in Guangdong province from 2012 to 2016. Methods: The data of mild HFMD cases caused by Cox A16 were collected from 8 sentinel hospitals in 8 prefecture-level cities in Guangdong to estimate Cox A16 infection status and its population and time distribution characteristics. Results: (1) The highest estimated incidence of Cox A16 infection was in 2014 (113.0/100 000), followed by 2016 (86.4/100 000) and 2012 (79.1/100 000), while the estimated incidence was lower in 2015 (29.0/100 000) and 2013 (28.8/100 000). (2) Cox A16 was confirmed to be the predominant pathogen causing HFMD outbreaks (54.6%, 89/163). The number of outbreaks in the year with high incidence (28 outbreaks) was 11.2 times higher than that in the year with low incidence (2.5 outbreaks). (3) Across all age groups, the annual estimated incidence of Cox A16 infection decreased with age (trend χ(2)=853 905.63, P<0.01). The incidence was highest in age group 1 year (1 449.2/100 000), followed by that in age group 3 years (1 097.0/100 000), in age group 2 years (1 083.5/100 000), in age group 4 years (687.8/100 000) and in age group 0 year (604.9/100 000). Among the age groups <12 months, the estimated incidence increased with age (trend χ(2)=5 541.77, P<0.01), which was highest in age group 11-months (2 105.1/100 000), followed by that in age groups 10-months (1 448.6/100 000), 9-months (938.3/100 000), 8-months (703.3/100 000) and 6-months (664.6/100 000). (4) The annual incidence peak was during May (143.9/100 000)-June (131.5/100 000). Conclusion: The prevalence of Cox A16 infection differed with year in Guangdong during 2012-2016. When the incidence of Cox A16 infection was high, more outbreaks occurred. The prevalence occurred mainly in nurseries and kindergartens from May to June each year. Children aged 0-4 years were the high risk group for Cox A16 infection, children aged 6-11 months were at high risk for Cox A16 infection.

Advances in application of Jurkat cell model in research on infectious diseases / 中国当代儿科杂志

Infectious diseases can be caused by multiple pathogens, which can produce specific immune response in human body. The immune response produced by T cells is cellular immunity, which plays an important role in the anti-infection process of human body, and can participate in immunological protection and cause immunopathology. The outcome of various infectious diseases is closely related to cellular immune function, especially the function of T cells. Jurkat cells belong to the human acute T lymphocyte leukemia cell line. Jurkat cell model can simulate the function T lymphocytes, so it is widely used in the in vitro studies of T cell signal transduction, cytokines, and receptor expression, and can provide reference and guidance for the treatment of various infectious diseases and the research on their pathogenesis. The Jurkat cell model has been widely used in the in vitro studies of viral diseases and atypical pathogens, but parasitic infection studies using the Jurkat cell model are still rare. This article reviews advances in the application of Jurkat cell model in the research on infectious diseases.

Association of TLR3-1377C/T gene polymorphisms and expression with susceptibility to enterovirus 71 encephalitis in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the association of gene polymorphisms of Toll-like receptor 3 (TLR3)-1377C/T and expression of TLR3 with the susceptibility to enterovirus 71 (EV71) encephalitis in children.</p><p><b>METHODS</b>A total of 187 children with EV71 infection (59 children in the encephalitis group and 128 in the non-encephalitis group) and 232 children who underwent physical examination were enrolled in the case-control study. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the TLR3-1377C/T gene polymorphisms. ELISA was used to measure the serum level of TLR3.</p><p><b>RESULTS</b>There were no significant differences in the genotype and allele frequencies of TLR3-1377C/T between the non-encephalitis group and the encephalitis group. Compared with the control group, the encephalitis group and the non-encephalitis group had significant increases in the serum level of TLR3 (P<0.05), and the non-encephalitis group had the highest level (P<0.05). The encephalitis group had a significantly higher EV71 viral load than the non-encephalitis group (P<0.01). The children aged <1 year or ≥1 year in the encephalitis group and the non-encephalitis group had significant increases in the serum level of TLR3 compared with their counterparts in the control group (P<0.05), and the children aged <1 year or ≥1 year in the non-encephalitis group had a significantly higher serum level of TLR3 than those in the encephalitis group (P<0.05). In the encephalitis group, the children aged ≥1 year had a significantly higher TLR3 concentration than those aged <1 year (P<0.05), and there were no significant differences in the TLR3 concentration between the children aged ≥1 year and <1 year in the non-encephalitis group and the control group. In the encephalitis group, the proportion of children aged <1 year was significantly higher than those aged ≥1 year (P<0.05).</p><p><b>CONCLUSIONS</b>The TLR3-1377C/T gene polymorphisms are not significantly associated with the development of EV71 encephalitis. Low expression of TLR3 might weaken the inhibitory effect on virus replication and promote the development of EV71 encephalitis. The deficiency in the expression of TLR3 in serum after EV71 infection might be an important factor for the development of encephalitis in infants.</p>

The binding of a monoclonal antibody to the apical region of SCARB2 blocks EV71 infection

Entero virus 71 (EV71) causes hand, foot, and mouth disease (HFMD) and occasionally leads to severe neurological complications and even death. Scavenger receptor class B member 2 (SCARB2) is a functional receptor for EV71, that mediates viral attachment, internalization, and uncoating. However, the exact binding site of EV71 on SCARB2 is unknown. In this study, we generated a monoclonal antibody (mAb) that binds to human but not mouse SCARB2. It is named JL2, and it can effectively inhibit EV71 infection of target cells. Using a set of chimeras of human and mouse SCARB2, we identified that the region containing residues 77-113 of human SCARB2 contributes significantly to JL2 binding. The structure of the SCARB2-JL2 complex revealed that JL2 binds to the apical region of SCARB2 involving α-helices 2, 5, and 14. Our results provide new insights into the potential binding sites for EV71 on SCARB2 and the molecular mechanism of EV71 entry.

Contribution of 3CD Region to the Virulence of Enterovirus 71 / 生物医学与环境科学（英文）

Enterovirus 71 is a neuroinvasive virus that is associated with severe neurological complications. We had earlier suggested that the replication capacity of a severe strain was higher than that of a mild strain. The recombinant 3CRV and 3CDRV virus strains were successfully rescued in our previous study. In the present study, we found no difference in virulence between 3CRV and severe strains. However, the capacity of replication and to cause cell injury of 3CDRV strain decreased in vitro, especially at 39.5 °C. Replacement of 3CD region in the severe strain led to milder symptoms, less body weight loss, and lower viral load in ICR mice. Histopathological findings indicated less severe injury in mice infected with 3CDRV strain. This study suggests that the 3CD region contributes to the attenuation of the severe strain, including its replication capacity and temperature sensitivity.

Rapid and Accurate Sequencing of Enterovirus Genomes Using MinION Nanopore Sequencer / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Knowledge of an enterovirus genome sequence is very important in epidemiological investigation to identify transmission patterns and ascertain the extent of an outbreak. The MinION sequencer is increasingly used to sequence various viral pathogens in many clinical situations because of its long reads, portability, real-time accessibility of sequenced data, and very low initial costs. However, information is lacking on MinION sequencing of enterovirus genomes.</p><p><b>METHODS</b>In this proof-of-concept study using Enterovirus 71 (EV71) and Coxsackievirus A16 (CA16) strains as examples, we established an amplicon-based whole genome sequencing method using MinION. We explored the accuracy, minimum sequencing time, discrimination and high-throughput sequencing ability of MinION, and compared its performance with Sanger sequencing.</p><p><b>RESULTS</b>Within the first minute (min) of sequencing, the accuracy of MinION was 98.5% for the single EV71 strain and 94.12%-97.33% for 10 genetically-related CA16 strains. In as little as 14 min, 99% identity was reached for the single EV71 strain, and in 17 min (on average), 99% identity was achieved for 10 CA16 strains in a single run.</p><p><b>CONCLUSION</b>MinION is suitable for whole genome sequencing of enteroviruses with sufficient accuracy and fine discrimination and has the potential as a fast, reliable and convenient method for routine use.</p>

Association between S100B gene polymorphisms and hand, foot and mouth disease caused by enterovirus 71 infection / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the association between rs9722 polymorphisms in the S100B gene and hand, foot and mouth disease (HFMD) caused by enterovirus 71.</p><p><b>METHODS</b>A total of 124 HFMD children with enterovirus 71 infection were enrolled as subjects, and 56 healthy children were enrolled as control group. The rs9722 polymorphisms in the S100B gene were detected for both groups, and the serum level of S100B protein was measured for 74 HFMD children.</p><p><b>RESULTS</b>The rs9722 locus of the S100B gene had three genotypes, CC, CT, and TT, and the genotype frequencies were in accordance with Hardy-Weinberg equilibrium. Compared with the control group, the HFMD group had significant increases in the frequencies of TT genotype and T allele (P<0.01). Children with severe HFMD caused by enterovirus 71 infection had significantly higher frequencies of TT genotype and T allele than those with moderate or mild HFMD (P<0.05). Compared with the cured patients, the patients with poor prognosis had significant increases in the frequencies of TT genotype and T allele in the rs9722 locus of the S100B gene (P<0.05). Among the 74 children with HFMD, the children with TT genotype had the highest serum level of S100B protein, and those with CC genotype had the lowest level (P<0.01).</p><p><b>CONCLUSIONS</b>T allele in the rs9722 locus of the S100B gene might be a risk factor for severe HFMD caused by enterovirus 71 infection.</p>