Clinical and neuroimaging features of enterovirus71 related acute flaccid paralysis in patients with hand-foot-mouth disease

Objective:To investigate clinical and neuroimaging features of enterovirus71(EV71) related acute flaccid paralysis in patients with hand-fool-mouth disease.Methods:Nine patients with acute flaccid paralysis met the criterion of EV71 induced hand-foot-mouth disease underwent spinal and brain MR imaging from May 2008 to Sep 2012.Results:One extremity flaccid was found in four cases(3 with lower limb,1 with upper limb),two limbs flaccid in three cases(2 with lower limbs,1 with upper limbs),and four limbs flaccid in two cases.Spinal MRI studies showed lesion with high signal in T2-weighted images(T2WI) and low signal T1-weighted images(T1WI) in the spinal cord of all nine cases,and the lesions were mainly in bilateral and unilateral anterior hom of cervical spinal cord and spinal cord below thoracic 9(T9) level.In addition,the midbrain,pons, and medulla,which were involved in 3 cases with brainstem encephalitis,demonstrated abnormal signal.Moreover,spinal cord contrast MRI studies showed mild enhancement in corresponding anterior hom of the involved side,and strong enhancement in its ventral root.Conclusions: EV71 related acute flaccid paralysis in patients with hand-foot-mouth disease mainly affected the anterior hom regions and ventral root of cervical spinal cord and spinal cord below T9 level. MR imaging could efficiendy show the characteristic pattern and extent of the lesions which correlated well with the clinical features.

Molecular Epidemiology of Enteroviruses Associated with Hand, Foot, and Mouth Disease in the Mainland of China

Hand, foot, and mouth disease （HFMD） is a common contagious illness which occurs worldwide both sporadically and in epidemics. The disease mainly affects, children and the typical symptoms, which may resolve spontaneously, include mucocutaneous papulovesicular lesions on the hands, feet, mouth, and buttocks. In rare cases, however, the patients may also develop neurological complications such as neurogenic pulmonary edema,

RT-nPCR Assays for Amplification and Sequencing of VP1 Genes in Human Enterovirus A–D from Clinical Specimens

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 CCID50 perμL and copies perμL,and the newly established methods were tested in clinical specimens collected in recent years.Results The sensitivity of RT-nPCR assays for amplifying partial VP1 gene of HEVs was 0.1 CCID50 perμL and 10 virus copies perμL,and for the complete VP1 gene was 1 CCID50 perμL and 100 virus copies perμL,using serially-diluted virus stocks of five serotypes.As a proof-of-concept,25 serotypes were identified and complete VP1 sequences of 23 serotypes were obtained by this system among 858 clinical specimens positive for HEVs during the past eight surveillance seasons.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.

Comparative Genomic Analysis of Enterovirus 71 Revealed Six New Potential Neurovirulence-associated Sites

In the present study,the complete genomes of four common（4/EV71/Wenzhou/CHN/2014,15/EV71/Wenzhou/CHN/2014,116/EV71/Wenzhou/CHN/2014,and 120/EV71/Wenzhou/CHN/2014）and two virulent（11/EV71/Wenzhou/CHN/2014and 109/EV71/Wenzhou/CHN/2014）enterovirus 71（EV71）isolates were sequenced and described.They are 7405 bp in length and belong to EV71 sub-genotype C4 （C4a cluster）.

Human IgG Fc promotes expression, secretion and immunogenicity of enterovirus 71 VP1 protein

Enterovirus （EV71） can cause severe neurological diseases, but the underlying pathogenesis remains unclear. The capsid protein, viral protein 1 （VP1）, plays a critical role in the pathogenicity of EVT1. High level expression and secretion ofVP 1 protein are necessary for structure, function and immunogenicity in its natural conformation. In our previous studies, 5 codon-optimized VP 1 DNA vaccines, including wt-VP 1, tPA-VP 1, VP l-d, VP 1-hFc and VP 1 - mFc, were constructed and analyzed. They expressed VP1 protein, but the levels of secretion and immunogenicity of these VP1 constructs were significantly different （P〈0.05）. In this study, we further investigated the protein lev- els of these constructs and determined that all of these constructs expressed VP1 protein. The secretion level was increased by including a tPA leader sequence, which was further increased by fusing human IgG Fc （hFc） to VP1. VP 1-hFc demonstrated the most potent immunogenicity in mice. Furthermore, hFc domain could be used to purify VPI-hFc protein for additional studies.

Therapeutic and prevention strategies against human enterovirus 71 infection

Human enterovirus 71(HEV71) is the cause of hand,foot and mouth disease and associated neurological complications in children under five years of age.There has been an increase in HEV71 epidemic activity throughout the Asia-Pacific region in the past decade,and it is predicted to replace poliovirus as the extant neurotropic enterovirus of highest global public health significance. To date there is no effective antiviral treatment and no vaccine is available to prevent HEV71 infection. The increase in prevalence, virulence and geographic spread of HEV71 infection over the past decade provides increasing incentive for the development of new therapeutic and prevention strategies against this emerging viral infection. The current review focuses on the potential, advantages and disadvantages of these strategies. Since the explosion of outbreaks leading to large epidemics in China, research in natural therapeutic products has identified several groups of compounds with anti-HEV71 activities. Concurrently, the search for effective synthetic antivirals has produced promising results. Other therapeutic strategies including immunotherapy and the use of oligonucleotides have also been explored. A sound prevention strategy is crucial in order to control the spread of HEV71. To this end the ultimate goal is the rapid development, regulatory approval and widespread implementation of a safe and effective vaccine. The various forms of HEV71 vaccine designs are highlighted in this review. Given the rapid progress of research in this area, eradication of the virus is likely to be achieved.

Intravenous vitamin C as adjunctive therapy for enterovirus/rhinovirus induced acute respiratory distress syndrome

We report a case of virus-induced acute respiratory distress syndrome(ARDS) treated with parenteral vitamin C in a patient testing positive for enterovirus/rhinovirus on viral screening. This report outlines the first use of high dose intravenous vitamin C as an interventional therapy for ARDS, resulting from enterovirus/rhinovirus respiratory infection. From very significant preclinical research performed at Virginia Commonwealth Universitywith vitamin C and with the very positive results of a previously performed phase Ⅰ safety trial infusing high dose vitamin C intravenously into patients with severe sepsis, we reasoned that infusing identical dosing to a patient with ARDS from viral infection would be therapeutic. We report here the case of a 20-year-old, previously healthy, female who contracted respiratory enterovirus/rhinovirus infection that led to acute lung injury and rapidly to ARDS. She contracted the infection in central Italy while on an 8-d spring break from college. During a return flight to the United States, she developed increasing dyspnea and hypoxemia that rapidly developed into acute lung injury that led to ARDS. When support with mechanical ventilation failed, extracorporeal membrane oxygenation(ECMO) was initiated. Twelve hours following ECMO initiation, high dose intravenous vitamin C was begun. The patient's recovery was rapid. ECMO and mechanical ventilation were discontinued by day-7 and the patient recovered with no long-term ARDS sequelae. Infusing high dose intravenous vitamin C into this patient with virus-induced ARDS was associated with rapid resolution of lung injury with no evidence of post-ARDS fibroproliferative sequelae. Intravenous vitamin C as a treatment for ARDS may open a new era of therapy for ARDS from many causes.

Coxsackievirus A6 was the most common enterovirus serotype causing hand,foot,and mouth disease in Shiyan City,central China

BACKGROUND Hand,foot,and mouth disease(HFMD)has become one of the most common infectious diseases in China.Before 2016,the primary causal serotypes were enterovirus A71(EV-A71)and coxsackievirus A16(CV-A16).Following the introduction of EV-A71 vaccines in China since 2016,the situation could change.CV-A6 has recently replaced EV-A71 and CV-A16 in some areas of China.However,the epidemiological characteristics of central China remain unknown.AIM To investigate the clinical symptoms and pathogen spectrum of HFMD in Shiyan City,central China,in recent years.METHODS The epidemiological,clinical,and laboratory data from HFMD cases reported to the Shiyan Center for Disease Control and Prevention between January 2016 and December 2020 were analyzed.196 throat swab specimens were collected from hospitalized HFMD patients between January 2018 and December 2020.To detect and genotype enteroviruses,real-time reverse transcription-polymerase chain reaction and sequencing of the 5'-untranslated region were used.In Shiyan,168 laboratory-confirmed HFMD cases were studied using a logistic regression model to determine the effect of predominant enterovirus serotypes.Based on the logistic regression model,the least absolute shrinkage and selection operator model was used to analyze the correlation between CV-A6 infection and various clinical characteristics in HFMD patients in Shiyan.RESULTS From 2016 to 2020,35840 HFMD cases were reported in Shiyan.The number of cases decreased by 48.4%from 2016 to 2017.Approximately 1.58-fold increases were found in 2018 and 2019 when compared to the previous year,respectively.In 2020,a decrease of about 85.5%was reported when compared to 2019.The most common serotypes shifted from EV-A71 and CV-A16(about 60%-80%in 2016 and 2018)to others(more than 80.0%in 2017,2019,and 2020).EV-A71 lost its dominance in 2017 in Shiyan.Among 196 confirmed HFMD cases,85.7%tested positive for enterovirus,with CV-A6 being the most common serotype(121/168,72.0%).The positive rates for CV-A16 and CVA10 were 4.8%and 3.0%,respectively.There was no EV-A71 discovered.Infection with CV-A6 was linked to fever,myocardial damage,increased creatine kinase MB isoenzyme,and lactate dehydrogenase levels.CONCLUSION CV-A6 was the most common enterovirus serotype in Shiyan City,replacing EV-A71 and CV-A16 as the HFMD pathogen.Developing vaccines against CV-A6 or multiple pathogens,as well as rising CV-A6 surveillance,will help prevent HFMD in central China.

Detection and quantification of enteroviruses in coastal seawaters from Bohai Bay,Tianjin,China

An 8-month survey was conducted to detect and quantify enteroviruses in Tianjin coastal seawaters of Bohai Bay to assess coastal water quality. Ten water samples were collected from Bohai Bay for the detection and quantification of enteroviruses by conventional reverse transcription polymerase chain reaction （RT-PCR） and SYBR Green real-time quantitative RT-PCR （qRT-PCR）. Total viral nucleic acid was extracted from 500 mL of seawater samples concentrated by Centricon plus-70 centrifugal filter devices. The viral recovery rate was 29.1% based on viral seeding study. The centrifugal ultrafiltration method applied is effective for viral recovery from small volume of polluted water, which may have broader applications to monitoring human virus in aquatic environment. Our results indicated that there was a severe viral contamination in seawater of Bohai Bay. Enteroviruses were detected at concentrations ranging from 1.7 × 10^6 to 6.3 × 10^7 copies/L by qRT-PCR. Sequencing analyses identified that all of the twenty clones as poliovirus type 2. This is the first quantitative report of human viruses in coastal waters of a metropolitan city in China. This study emphasized the importance for the local and central governmertts to monitor and assess the water quality.

Evaluation of Reverse Transcription Loop-Mediated Isothermal Amplification assays for Rapid Detection of Human Enterovirus 71 and Coxsackievirus A16 in Clinical Samples

A sensitive reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for human enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16) infection was further evaluated. The one step reaction was performed in a single tube at 65?C for 45 min for EV71 and 35 min for CVA16. The detection limits of RT-LAMP assays for both EV71 and CVA16 were 0.1 of a 50% tissue culture infective dose (TCID50) per reaction, based on 10—Fold dilutions of a titrated EV71 or CVA16 strain. The specific assay showed there were no cross-reactions with Coxsackievirus A (CVA) viruses (CVA 2, 4, 5, 7, 9, 10, 14, and 25), Coxsackievirus B (CVB) viruses (CVB 1, 2, 3, 4, and 5) or ECHO viruses (ECHO 3, 6, 11, and 19). In parallel with commercial quantitative real-time polymerase chain reaction (qRT-PCR) diagnostic kits for EV71 and CVA16, the RT-LAMP assay was evaluated with 515 clinical specimens, the results showed the RT-LAMP assay and the qRT-PCR assay were in complete agreement for 513/515 (99.6%) of the specimens. Two samples with discrepant results from two methods were further verified by nested reverse transcription polymerase chain reaction (nRT-PCR) assay and sequencing to be true positives for CVA16. In conclusion, RT-LAMP assay is demonstrated to be a sensitive and specific assay and have a great potential for the rapid and visual screening of EV71 and CVA16 in China, especially in those resource-limited hospitals and rural clinics of provincial and municipal regions.

Rapid and Accurate Sequencing of Enterovirus Genomes Using MinION Nanopore Sequencer

Objective 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. Methods 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. Results 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. Conclusion 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.

Pancreatitis in hand-foot-and-mouth disease caused byenterovirus 71

Some viruses, including certain members of the enterovirus genus, have been reported to cause pancreatitis, especially Coxsackie virus. However, no case of human enterovirus 71(EV71) associated with pancreatitis has been reported so far. We here report a case of EV71-induced hand-foot-and-mouth disease(HFMD) presenting with pancreatitis in a 2-year-old girl. This is the first report of a patient with acute pancreatitis in HFMD caused by EV71. We treated the patient conservatively with nasogastric suction, intravenous fluid and antivirals. The patient's symptoms improved after 8 d, and recovered without complications. We conclude that EV71 can cause acute pancreatitis in HFMD, which should be considered in differential diagnosis, especially in cases of idiopathic pancreatitis.

Human Enterovirus 71 DNA Vaccine Constructs Containing 5’UTR with Complete Internal Ribosome Entry Site Sequence Stimulated Improved Anti-Human Enterovirus 71 Neutralizing Immune Responses

Recent improvement in the technologies for efficient delivery of DNA vaccines has renewed interest in the DNA-based vaccines. Several DNA-based vaccines against human enterovirus 71 (EV71), the causative agent for hand, foot and mouth disease (HFMD) have been developed. Here we examined the potential of improving the vaccines by inserting the EV71 5’ untranslated region (5’ UTR) containing the full length internal ribosome entry site (IRES) sequence to the EV71 VP1-based DNA vaccine constructs. Four vaccine constructs designated as 5’ UTR-VP1/EGFP, VP1/EGFP, 5’ UTR-VP1/pVAX and VP1/pVAX, were designed using the pEGFP-N1 and pVAX-1 expression vectors, respectively. Transfection of Vero cells with the vaccine constructs with the 5’-UTR (5’-UTR-VP1/EGFP and 5’ UTR-VP1/pVAX) resulted in higher percentages of cells expressing the recombinant protein in comparison to cells transfected with vectors without the 5’-UTR (67% and 57%, respectively). Higher IgG responses (29%) were obtained from mice immunized with the DNA vaccine construct with the full length 5’ UTR. The same group of mice when challenged with life EV71 produced significantly higher neutralizing antibody (NAb) titers (>5-fold). These results suggest that insertion of the EV71 5’ UTR sequence consisting of the full length IRES to the EV71 DNA vaccine constructs improved the efficacy of the constructs with enhanced elicitation of the neutralizing antibody responses.

The Genomic Characterization of Enterovirus D68 from 2011 to 2015 in Beijing, China

A retrospective surveillance study on enterovirus D68 was performed in Beijing, China, following the largest and most widespread EV-D68 infection, which occurred in the USA. From January 2011 to July 2015, EV-D68 was identified in 12 individuals with respiratory infections in Beijing, China. The phylogenetic relationships based on the genomic sequence alignment showed that there were two lineages circulating in Beijing from 2011 to 2015. Eight EV-D68 strains belonged to group 1 and four belonged to group 3. All EV-D68 strains from Beijing in 2014 were separately clustered into subgroup II of group 1. Based on these results, we concluded that the Beijing EV-D68 strains had little association with the EV-D68 strains circulating in the 2014 USA outbreak.

Safe and Objective Assay of Enterovirus 71 Neutralizing Antibodies via Pseudovirus

Current serum neutralization assays based on the inhibition of the cytopathic effect（Nt-CPE） need to ma nipulate live viruses, which are time-consuming, labor-intensive, and have the potential exposure to infectious agents, so a safe and objective assay via pseudovirus for the fast and efficient detection of enterovirus 71（EV71） neutralizing antibodies was developed. First, we generated EV71 pseudovirus containing firefly luciferase gene in place of the capsid gene P1 in EV71 genome. Vero cells infected with 200 CCID50（50% cell culture infective dose） of EV71 pseudovirus for 24 h were found to have the best performance. Seval sera were measured by EV71 pseudoparticle neutralization assay（Nt-PPN） and the conventional serological method Nt-CPE. Neutralizing antibody titers measured by Nt-PPN and those obtained by Nt-CPE demonstrate a high correlation between the two methods. Overall, the PPN assay represents a valid alternative to conventional serological methods for the evaluation of EV71 neutralizing anti bodies. This method can be used for detecting neutralizing antibodies of other picornaviruses, such as hepatitis A vi rus（HAV） and coxsackievirus 16（CVA16）, and make it possible to determine whether there is cross-reactivity be tween EV71 and CVA16.

Functional Dyspepsia and Chronic Gastritis Associated with Enteroviruses

After decades of research, functional dyspepsia (FD) remains one of the most elusive gastrointestinal disorders. Endoscopic appearance of mild inflammation of the gastric mucosa without ulceration and microscopic evidence of mild chronic inflammation are often considered as normal findings since no etiology could be found other than H. Pylori. Enteroviruses infect the gastrointestinal tract and have been shown to persist in the stomach of symptomatic patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). In this study, we evaluated FD patients with and without the diagnosis of ME/CFS, and were able to support the viral protein staining with finding of double-stranded RNA in 63% of the same stomach biopsies by immunoperoxidase staining. Furthermore, we clarified the possible cross-reaction with creatine kinase brain subtype (CKB), present in parietal cells, using antibody competition experiments and western blot analysis of stomach proteins. Viral protein+ and dsRNA+ biopsies were infectious in SCID mice. More research is needed to elucidate the mechanism of enterovirus infection of the stomach associated with FD and chronic gastritis.

A Functionalized Multi-walled Carbon Nanotube and Gold Nanoparticle Composite-modified Glassy Carbon Electrode for the Detection of Enterovirus 71

Hand, foot, and mouth disease (HFMD) is a common infectious disease in children, occurring primarily in preschool children[1_3] with infants under three years old being gen erally susceptible. The disease is caused by various enteroviruses, among which EV71 and Coxsackievirus A group 16 (Cox A16) are the most comm on ⑷.According to in formation released by the Chinese Center for Disease Control and Prevention on June 8, 2016, EV71 infection- related HFMD has been prevalent among infants and young children in China since 2007, with a high incidenee and many deaths.

Enterovirus and type 1 diabetes: What is the matter?

A complex interaction of genetic and environmental factors can trigger the immune-mediated mechanism responsible for type 1 diabetes mellitus(T1DM) establishment. Environmental factors may initiate and possibly sustain, accelerate, or retard damage to β-cells. The role of environmental factors in this process has been exhaustive studied and viruses are among the most probable ones, especially enteroviruses. Improvements in enterovirus detection methods and randomized studies with patient follow-up have confirmed the importance of human enterovirus in the pathogenesis of T1 DM. The genetic risk of T1 DM and particular innate and acquired immune responses to enterovirus infection contribute to a tolerance to T1DM-related autoantigens. However, the frequency, mechanisms, and pathways of virally induced autoimmunity and β-cell destruction in T1 DM remain to be determined. It is difficult to investigate the role of enterovirus infection in T1 DM because of several concomitant mechanisms by which the virus damages pancreatic β-cells, which, consequently, may lead to T1 DM establishment. Advances in molecular and genomic studies may facilitate the identification of pathways at earlier stages of autoimmunity when preventive and therapeutic approaches may be more effective.

Evolutionary pattern of 5'-UTR of enteroviruses and primer update for the detection of enteroviral RNA in environmental samples

Objective:To study the recombination events among enterovirus strains and the development of specific primers for the detection of enteroviruses in environmental samples.Methods: Nucleotide sequence analysis of enteroviruses deposited in the international database GenBank （www.ncbi.nlm.nih.gov/Genbank） was conducted to develop specific primers for the detection of these viruses.The specificity and sensitivity of the method were tested using coxackicvirus B3 strain Nancy,environmental isolate of human hepatitis A virus and human rotavirus strain WA.Seventy sewage samples were analyzed.Results:Enterovirus genome was detected in all positive samples.The genome of enterovirus was not detected in negative samples.The level of detection of these viruses was 102 TCID50mI..Conclusions:The development of new primers is an important issue for the detection of enteroviruses in the environment and the assessment of risk factors to human health.

Contribution of 3CD Region to the Virulence of Enterovirus 71

Enterovirus 71 （EV71） and Coxsackievirus A16 （CoxA16） are the major pathogens causing hand, foot, and mouth disease （HFMD） that occurs primarily in children and infants with mild clinical manifestations. HFMD caused by EV71 could develop to a fatal neurological complication.