Coxsackievirus A6 and Hand, Foot and Mouth Disease: Three Case Reports of Familial Child-to-Immunocompetent Adult Transmission and a Literature Review

Exploring the Birthday Week Effect on Hand, Foot, and Mouth Disease in Yunnan Province, China, From 2008 to 2022: Surveillance Data Analysis

Background

Hand, foot, and mouth disease (HFMD) is a notable infectious disease predominantly affecting infants and children worldwide. Previous studies on HFMD have primarily focused on natural patterns, such as seasonality, but research on the influence of important social time points is lacking. Several studies have indicated correlations between birthdays and certain disease outcomes.

Objective

This study aimed to explore the association between birthdays and HFMD.

Methods

Surveillance data on HFMD from 2008 to 2022 in Yunnan Province, China, were collected. We defined the period from 6 days before the birthday to the exact birthday as the "birthday week." The effect of the birthday week was measured by the proportion of cases occurring during this period, termed the "birthday week proportion." We conducted subgroup analyses to present the birthday week proportions across sexes, age groups, months of birth, and reporting years. Additionally, we used a modified Poisson regression model to identify conditional subgroups more likely to contract HFMD during the birthday week.

Results

Among the 973,410 cases in total, 116,976 (12.02%) occurred during the birthday week, which is 6.27 times the average weekly proportion (7/365, 1.92%). While the birthday week proportions were similar between male and female individuals (68,849/564,725, 12.19% vs 48,127/408,685, 11.78%; χ21=153.25, P<.001), significant differences were observed among different age groups (χ23=47,145, P<.001) and months of birth (χ211=16,942, P<.001). Compared to other age groups, infants aged 0-1 year had the highest birthday week proportion (30,539/90,709, 33.67%), which is 17.57 times the average weekly proportion. Compared to other months, patients born from April to July and from October to December, the peak months of the HFMD epidemic, had higher birthday week proportions. Additionally, a decreasing trend in birthday week proportions from 2008 to 2022 was observed, dropping from 33.74% (3914/11,600) to 2.77% (2254/81,372; Cochran-Armitage trend test: Z=-102.53, P<.001). The results of the modified Poisson regression model further supported the subgroup analyses findings. Compared with children aged >7 years, infants aged 0-1 year were more likely to contract HFMD during the birthday week (relative risk 1.182, 95% CI 1.177-1.185; P<.001). Those born during peak epidemic months exhibited a higher propensity for contracting HFMD during their birthday week. Compared with January, the highest relative risk was observed in May (1.087, 95% CI 1.084-1.090; P<.001).

Conclusions

This study identified a novel "birthday week effect" of HFMD, particularly notable for infants approaching their first birthday and those born during peak epidemic months. Improvements in surveillance quality may explain the declining trend of the birthday week effect over the years. Higher exposure risk during the birthday period and potential biological mechanisms might also account for this phenomenon. Raising public awareness of the heightened risk during the birthday week could benefit HFMD prevention and control.

Unilateral acute idiopathic maculopathy related to hand-foot-mouth disease: Case report and literature review

Unilateral acute idiopathic maculopathy (UAIM) is a rare disease that may cause unilateral vision loss in young adults after a flu-like illness. Occasionally, it is associated with hand-foot-mouth disease (HFMD) and is often underdiagnosed. Herein, we report a case with characteristics of UAIM associated with HFMD with acute enteroviral infection. On the basis of the clinical findings using multimodality diagnostic imaging, including fundus image, optical coherence tomography, fluorescence angiography, and serological test for pan-enterovirus RNA polymerase chain reaction, we detailed the clinical course and postulated the pathogenesis of UAIM with choroiditis associated with HFMD. This study could remind every doctor of the potential visual loss caused by UAIM in HFMD, and referring patients to the ophthalmologic survey is important to eliminate potential visual impairment.

Molecular epidemiology of hand, foot, and mouth disease in Karnataka, India in 2022

BACKGROUND

Hand, foot, and mouth disease (HFMD) is an enteroviral disease that occurs as outbreaks and sporadic cases in India. In this study, we investigated and characterized the aetiology of HFMD cases that occurred in Karnataka, South India from April to October 2022.

METHODS

Throat swabs, vesicular swabs, urine, and blood samples from suspected cases were analysed by reverse transcription polymerase chain reaction (RT-PCR) for the detection of enteroviruses. Molecular typing of the enterovirus-positive samples was carried out by amplifying the partial virion protein 1(VP1) gene sequence, followed by sequencing and phylogenetic analysis.

RESULTS

Out of the 187 samples received from 82 cases, 93 (50%) tested positive (55/82 cases, 67%) for enteroviruses, with the majority of the HFMD cases reported in paediatric population of less than 5 years (36/55, 65.4%), while 3 cases (3/55, 5.4%) were adults. Out of the 55 enterovirus-positive cases, 31 showed partial VP1 region amplification and 19 of these cases were typed as coxsackievirus A16 (CV-A16) (13/19, 68.4%) and CV-A6 (6/19, 31.6%). The CV-A16 strains identified belonged to subclade B1c while two CV-A6 strains belonged to subclade E2. On molecular testing for other viruses causing fever-rash symptoms, 4/27 (15%) enterovirus-negative cases were detected as herpes simplex virus (1 case) and varicella zoster virus (3 cases) positive.

CONCLUSION

The main causative agent of HFMD in Karnataka in 2022 was CV-A16, followed by CV-A6. Apart from the common paediatric HFMD cases, adult cases were also reported during this period. Further studies involving laboratory and clinical investigations are essential for monitoring and managing HFMD in the community.

Global emergence of Enterovirus 71: a systematic review

Background

Hand, foot, and mouth disease (HFMD) is a viral infection caused by a virus from the enterovirus genus of picornavirus family that majorly affects children. Though most cases of HFMD do not cause major problems, the outbreaks of Enterovirus 71 (EV71) can produce a high risk of neurological sequelae, including meningoencephalitis, lung difficulties, and mortality. In Asia, HFMD caused by EV71 has emerged as an acutely infectious disease of highly pathogenic potential, which demands the attention of the international medical community.

Main body of the abstract

Some online databases including NCBI, PubMed, Google Scholar, ProQuest, Scopus, and EBSCO were also accessed using keywords relating to the topic for data mining. The paid articles were accessed through the Centre Library facility of Siksha O Anusandhan University. This work describes the structure, outbreak, molecular epidemiology of Enterovirus 71 along with different EV71 vaccines. Many vaccines have been developed such as inactivated whole-virus live attenuated, subviral particles, and DNA vaccines to cure the patients. In Asia–Pacific nations, inactivated EV71 vaccination still confronts considerable obstacles in terms of vaccine standardization, registration, price, and harmonization of pathogen surveillance and measurements.

Short conclusion

HFMD has emerged as a severe health hazard in Asia–Pacific countries in recent decades. In Mainland China and other countries with high HFMD prevalence, the inactivated EV71 vaccination will be a vital tool in safeguarding children's health. When creating inactivated EV71 vaccines, Mainland China ensured maintaining high standards of vaccine quality. The Phase III clinical studies were used to confirm the safety and effectiveness of vaccinations.

Graphical Abstract

Hand, foot, and mouth disease in adults caused by Coxsackievirus B1-B6

Hand, foot, and mouth disease is a viral rickettsial disease caused by Coxsackievirus A16 and Enterovirus 71 in most cases. It is commonly seen in children under ten years old, who present oral enanthema and a macular, maculopapular, or vesicular rash on their hands and feet. However, an increase in cases caused by other viral serotypes was observed in adults in recent years with various clinical presentations and a troublesome diagnosis. Three cases of hand, foot, and mouth disease are reported to show the clinical variability and diagnostic complexity that this disease may present in adult patients.

A case report of severe systemic infection with neurological HFMD symptoms followed by an accidental puncture of thumb during HFMD sample collection

A 34-year-old female clinical virology assistant was punctured with a contaminated lancet used for sampling from a suspected Hand, Foot, and Mouth disease (HFMD) patient. Five days after a puncture, the disease symptoms manifested, including high fever, ague, and stiff neck. Skin rashes suddenly appeared after day 6. Stiff neck and fever were relieved two days after the rash appeared, and rashes disappeared gradually by the next five days. Samples for molecular detection and virus cultivation were taken from the patient. Real-time PCR found the enteroviral RNA in the throat swab and skin rashes. The specific CPE of Enteroviruses appeared on the Vero cell line after three days of incubation. In this case transmission occurs through needle injury and results in the systemic disease, so unusual and unexpected viral transmission should be considered when dealing with samples.

Detection of coxsackievirus A6 in formalin-fixed, paraffin-embedded skin biopsy specimens using immunohistochemistry and real-time reverse-transcriptase PCR

Background

Hand, foot, and mouth disease (HFMD), classically a childhood viral infection, has an atypical and severe clinical presentation in adults. Coxsackievirus A6 is a leading cause of atypical HFMD, but current diagnostic methods utilizing formalin-fixed, paraffin-embedded skin biopsy specimens often lack sensitivity and specificity.

Methods

Formalin-fixed, paraffin-embedded skin biopsies from seven case patients with clinical and histopathological suspicion of atypical HFMD were evaluated by coxsackievirus A6 (CVA6) immunohistochemistry, enterovirus-specific conventional reverse transcriptase-PCR with subsequent Sanger sequencing targeting the 5'UTR, and CVA6-specific real-time PCR targeting the VP1 gene.

Results

The CVA6-specific antibody demonstrated appropriate antigen distribution and staining intensity in keratinocytes in all cases. Conventional RT-PCR and sequencing also detected the presence of enterovirus, and CVA6-specific real-time RT-PCR analysis identified CVA6.

Conclusion

Applying these immunohistochemistry and molecular techniques to formalin-fixed, paraffin-embedded tissues, CVA6 was determined to be the causative infectious agent in seven cases of atypical hand, foot, and mouth disease.

Incidence of Infection of Enterovirus 71 and Coxsackieviruses A6 and A16 among Household Contacts of Index Cases in Dong Thap Province, Southern Vietnam

Background

Scarce information exists about immunity to hand, foot, and mouth disease (HFMD) among household contacts of index cases in Vietnam and what that means for reducing ongoing HFMD transmission in the community.

Methods

We analyzed neutralizing antibodies (NT) and the incidence of enterovirus (EVs) infection among household contacts of index cases in a province where HFMD remains endemic. Throat swab and 2 mL blood samples from household contacts were collected at enrollment, during and after 2 weeks follow-up.

Results

The incidence of EV-A71 infection among household contacts was 40/84 (47.6%, 95% Cl: 36.9-58.3%), compared with 106/336 (31.5%, 95% Cl: 26.6-36.5%) for CV-A6 and 36/107 (33.6%, 95% Cl: 24.7-42.6%) for CV-A16. The incidence of CV-A6 infection was fairly constant across ages; in contrast, CV-A71 and CV-A16 had some variation across ages. At baseline, higher geometric mean titer (GMT) of EV-A71, CV-A6, and CV-A16 antibody titers was found for 25-34-year groups (range 216.3 to 305.0) compared to the other age groups. There was a statistically significant difference in GMT values of CV-A6 and CV-A16 between those who had an infection or did not have infection among households with an index case of these serotypes.

Conclusions

Our results indicated that adults were becoming infected with HFMD and could be contributing to the transmission. There is, therefore, a need for considering the household setting as an additional target for intervention programs for HFMD.

An unusual location of hand, foot and mouth disease

Hand, foot, and mouth disease (HFMD) is a childhood febrile disease. Oral lesions and papulovesicular lesions on the hands and feet are the clinical signs of the disease. In our case, a 17-year-old boy presented to the emergency department, where he was diagnosed with HFMD. After 6 days, he felt intense pain in his right testicle, and therefore an ultrasound (US) examination was performed. US detected a hypoechoic mass-like area in the right testis. Viral etiology was suspected, and no therapy was prescribed. After a little more than 3 months, US examination showed a reduced lesion size. Viral epididymo-orchitis should be suspected in young men with a recent history of HFMD and testicular pain.

Hand, Foot and Mouth Disease in Immunocompetent Adult with Severe Oral Manifestation

Hand-foot-mouth Disease (HFMD) is an acute, self-limited, and highly contagious disease caused by a virus and generally affects children under 10 years old. The etiology of this disease is enterovirus 71 or coxsackievirus A16 which usually causes symptomatic infection or mild disease. Immunocompetent adults are rarely affected. However, recently the incidence of HFMD in immunocompetent adults has increased. We report a 41-year-old woman with severe oral lesions and painful papulovesicular eruption on the palms of her hands and feet.

Bioinformatics Analysis of Key micro-RNAs and mRNAs under the Hand, Foot, and Mouth Disease Virus Infection

To clarify crucial key micro-RNAs and mRNAs associated with hand, foot, and mouth disease (HFMD) virus infection, we conducted this bioinformatics analysis from four GEO datasets. The following datasets were used for the analysis: GSE85829, GSE94551, GSE52780, and GSE45589. Differentially expressed genes (DEGs) were acquired, and the analysis of functional and pathway enrichment and the relative regulatory network were conducted. After screening common differentially expressed miRNAs (DE-miRNAs), five key miRNAs were acquired: miR-100-3p, miR-125a-3p, miR-1273g-3p, miR-5585-3p, and miR-671-5p. There were three common enriched GO terms between miRNA-derived prediction and mRNA-derived analysis: biosynthetic process, cytosol, and nucleoplasm. There was one common KEGG pathway, i.e., cell cycle shared between miRNA-based and mRNA-based enrichment. Using TarBase V8 in DIANA tools, we acquired 1,520 potential targets (mRNA) from the five key DE-miRNAs, among which the159 DE-mRNAs also included 11 DEGs. These common DEGs showed a PPI network mainly connected by SMC1A, SMARCC1, SF3B3, LIG1, and BRMS1L. Together, changes in five key miRNAs and 11 key mRNAs may play crucial roles in HFMD progression. A combination of these roles may benefit the early diagnosis and treatment of HFMD.

Human Antibodies to VP4 Inhibit Replication of Enteroviruses Across Subgenotypes and Serotypes, and Enhance Host Innate Immunity

Hand, foot, and mouth disease (HFMD) is a highly contagious disease that usually affects infants and young children (<5 years). HFMD outbreaks occur frequently in the Asia-Pacific region, and these outbreaks are associated with enormous healthcare and socioeconomic burden. There is currently no specific antiviral agent to treat HFMD and/or the severe complications that are frequently associated with the enterovirus of serotype EV71. Therefore, the development of a broadly effective and safe anti-enterovirus agent is an existential necessity. In this study, human single-chain antibodies (HuscFvs) specific to the EV71-internal capsid protein (VP4) were generated using phage display technology. VP4 specific-HuscFvs were linked to cell penetrating peptides to make them cell penetrable HuscFvs (transbodies), and readily accessible to the intracellular target. The transbodies, as well as the original HuscFvs that were tested, entered the enterovirus-infected cells, bound to intracellular VP4, and inhibited replication of EV71 across subgenotypes A, B, and C, and coxsackieviruses CVA16 and CVA6. The antibodies also enhanced the antiviral response of the virus-infected cells. Computerized simulation, indirect and competitive ELISAs, and experiments on cells infected with EV71 particles to which the VP4 and VP1-N-terminus were surface-exposed (i.e., A-particles that don’t require receptor binding for infection) indicated that the VP4 specific-antibodies inhibit virus replication by interfering with the VP4-N-terminus, which is important for membrane pore formation and virus genome release leading to less production of virus proteins, less infectious virions, and restoration of host innate immunity. The antibodies may inhibit polyprotein/intermediate protein processing and cause sterically strained configurations of the capsid pentamers, which impairs virus morphogenesis. These antibodies should be further investigated for application as a safe and broadly effective HFMD therapy.

Design, Synthesis, and Evaluation of Novel Enterovirus 71 Inhibitors as Therapeutic Drug Leads for the Treatment of Human Hand, Foot, and Mouth Disease

Human hand, foot, and mouth disease (HFMD) is a serious public health threat with high infection rates in children and infants who reside in Asia and the Pacific regions, and no effective drugs are currently available. Enterovirus 71 (EV71) and coxsackievirus A16 are the major etiological pathogens. Based on an essential hydrophobic pocket on the viral capsid protein VP1, we designed and synthesized a series of small molecular weight compounds as inhibitors of EV71. A potential drug candidate named NLD-22 exhibited excellent antiviral activity (with an EC₅₀ of 5.056 nM and a 100% protection rate for mice at a dose of 20 mg/kg) and low toxicity. NLD-22 had a favorable pharmacokinetic profile. High-resolution cryo-electron microscopy structural analysis confirmed NLD-22 bound to the hydrophobic pocket in VP1 to block viral infection. In general, NLD-22 was indicated to be a promising potential drug candidate for the treatment of HFMD.

Estimation of the reproduction number and identification of periodicity for HFMD infections in northwest China

Repeated outbreaks of Hand, foot and mouth disease (HFMD) infections have been observed in recent decades and dominated by various enteroviral serotypes. In particular, enterovirus 71 (EV-A71), coxsackievirus A16 (CV-A16) and coxsackievirus A6 (CV-A6) dominated the prevalence of HFMD infections alternatively in recent years with various outbreak sizes in Baoji, a city of Shaanxi Province in Northwest China. Estimating the reproduction number for various enteroviruses serotypes in northwest China (north temperate zone) and identification of cyclicity of HFMD infections are therefore an issue of great importance for future epidemics prediction and control. The basic/effective reproduction numbers for EV-A71, CV-A16 and CV-A6 were estimated based on daily new cases in 2010, 2011 and 2018, respectively, in which the corresponding pathogen dominated the epidemic. Two different methods based on serial interval were adopted and the basic reproduction number were estimated to be in the range of (1.33, 1.46) for CV-A16, (1.20, 1.29) for EV-A71, and (1.38, 1.59) for CV-A6, respectively. The estimated daily effective reproduction numbers significantly fluctuated before June or after July but varied mildly in (0.5,2) in around June to July for three serotypes. The weekly effective reproduction number for HFMD was estimated based on weekly new cases from year 2010 to 2018, and in most years it peaked in the range of (1.6,2.0) in February to March as well as in the range of (1.0,1.2) in September to October. The wavelet analysis based on the time series of HFMD cases from 2008 to 2018 showed obvious annual and semi-annual cyclicity, while the inter-annual cycles are infeasible. In this study we found that CV-A6 shows the greatest transmission ability among these three pathogens while EV-A71 exhibits the weakest ability of transmission, and moreover, the estimated values of basic reproduction number in northwest China are lower than those in Singapore, Hongkong and Guangdong, which may be due to different climatic circumstances.

Screening the Action Targets of Enterovirus 71 in Human SH-SY5Y Cells Using RNA Sequencing Data

Hand, foot, and mouth disease (HFMD) is a common infection for children younger than the age of five. HFMD is mainly induced by coxsackievirus A16 and enterovirus 71 (EV71). EV71-associated HFMD often has serious neurological disease complications. The purpose of this study was to reveal the mechanisms of action of EV71 on neurons. SH-SY5Y cells transfected or untransfected with EV71 were sequenced. After data preprocessing, differentially expressed genes (DEGs) were screened using the limma package in R, and clustering analysis was then performed using the ComplexHeatmap package in R. The DAVID tool was used for EDG enrichment analysis. Protein-protein interactions (PPIs) were predicted using the STRING database and PPI networks were then constructed using Cytoscape software. After pathways involved in the key PPI network nodes were enriched, pathway deviation scores were calculated. Clustering analysis was also conducted for these pathways. There were 978 DEGs in the transfected samples. Upregulated TNF was enriched in NF-kappa B signaling pathway. Among the top 20 nodes in the PPI network, CDK1, STAT3, CCND1, TNF, and MYC had the highest degrees. A total of 28 pathways were enriched for the top 20 nodes, including Epstein-Barr virus infection (p = 3.78E-06), proteoglycans in cancer (p = 4.96E-06), and melanoma (p = 1.99E-05). In addition, clustering analysis showed that these pathways could clearly differentiate the two groups of samples. EV71 may affect neurons by mediating CDK1, STAT3, CCND1, TNF, and MYC, indicating that these genes are promising targets for preventing the neuronal complications of HFMD.

A case report of a teenager with severe hand, foot, and mouth disease with brainstem encephalitis caused by enterovirus 71

BACKGROUND

Hand, foot, and mouth disease (HFMD) is an acute viral infection occurring mostly in infants and children. Enterovirus 71 (EV71) infection mostly occurs in children < 5 years of age. Severe cases, however, are usually encountered in children under the age of 3 years, and exceedingly rare in teenagers > 14 years and adults.

CASE PRESENTATION

We report a rare case of HFMD in a 16-year-old male teenager residing in Chonqing, China. The clinical presentation was typical of HFMD and included vesicular lesions and oral mucosal ulcers, macular and vesicular lesions on palms and soles. He developed severe neurological complications that were suggestive of brainstem encephalitis. EV71 RNA was detected in the patient's faecal samples by reverse transcription-polymerase chain reaction. Specific IgM antibody to EV71 was detected in both serum and cerebrospinal fluid by ELISA. Gamma immunoglobulin therapy at 25 g/day was administered for 2 days, along with methylprednisolone, mannitol, ganglioside, and creatine phosphate sodium. The patient showed neurological improvement and recovered completely in 1 month.

CONCLUSIONS

This case indicates that EV71 infection may cause HFMD in teenagers with potentially severe neurological involvement. Clinicians should be aware of the possibility of HFMD occurring in adults and teenagers as prompt treatment could be life-saving in these patients.

Central serous retinopathy and hand-foot-mouth disease: coincidence or causation?

Introduction

The clinical and pathological correlation between hand–foot–mouth disease (HFMD) and ocular complications has not yet been established. However, individual case reports indicate a trend that may be the emergence of a new burden of the previous self-limiting virus. This virus is particularly prevalent in childcare centers and poses an infectious disease risk for this workplace.

Objectives

The primary objective of this case report is to describe an unusual clinical record of a patient who developed central serous retinopathy while unwell with HFMD. Discussion of management strategies for this workplace, its staff, and visitors is also included.

Methods

This was an observational case report that was identified and reported retrospectively. For comparison, a search of the literature to identify similar ocular complications of HFMD was also undertaken. Results from this search, in addition to international data and prevention and management strategies are also provided.

Results

A total of 13 individual case reports with ocular associations, including this clinical record, were identified in the literature worldwide. The median age was 33 years, and three patients (23%) were female. No treatment or management guidelines for ocular complications of HFMD have been identified.

Conclusion

Severe and potentially life-threatening complications of a seemingly harmless childhood illness are represented sporadically in the literature. The requirement for research and evaluation into this emerging occupational hazard area is necessary for improved prevention, management, and treatment strategies to be developed.

Recent development of enterovirus A vaccine candidates for the prevention of hand, foot, and mouth disease

INTRODUCTION

Hand, foot, and mouth disease (HFMD) is a childhood illness commonly caused by enterovirus A. Enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16) are the most commonly identified viruses associated with HFMD. Recently, outbreaks caused by different enterovirus A including CV-A6 and CV-A10 are increasing. Being available now to protect against EV-A71 infection, inactivated EV-A71 vaccines cannot prevent coxsackievirus infections, thus limiting their general application in controlling HFMD. Multivalent HFMD vaccines are suggested to have broad cross-neutralizing responses against these emerging enteroviruses.

AREAS COVERED

We discuss the recent development of enterovirus A vaccines including the inactivated whole-virion vaccine and virus-like particle vaccine candidates and review the information of neutralization epitopes of these viruses.

EXPERT COMMENTARY

Evaluation of the efficacy and safety of the coxsackievirus vaccine and the multivalent HFMD vaccine candidates in clinical trials is urgently required. Epitopic analysis showed that common immunodominant sites exist across these enteroviruses. However, variations of amino acid residues in these regions limit the induction of cross-neutralization antibodies, and therefore, a multivalent HFMD vaccine is required for broad protection against HFMD. With the inclusion of major circulating viruses in the development of multivalent HFMD vaccines, an increase in the success in HFMD control is anticipated.

Paediatric Virology: A rapidly increasing educational challenge

The '2nd Workshop on Paediatric Virology', which took place on Saturday the 8th of October 2016 in Athens, Greece, provided an overview on recent views and advances on Paediatric Virology. Emphasis was given to HIV-1 management in Greece, a country under continuous financial crisis, hepatitis B vaccination in Africa, treatment options for hepatitis C virus in childhood, Zika virus in pregnancy and infancy, the burden of influenza on childhood, hand-foot-mouth disease and myocarditis associated with Coxsackie viruses. Other general topics covered included a critical evaluation of Paediatric Accident and Emergency viral infections, multimodality imaging of viral infections in children, surgical approaches of otolaryngologists to complex viral infections, new advances in the diagnosis and treatment of viral conjunctivitis and novel molecular diagnostic methods for HPV in childhood. A brief historical overview of the anti-vaccination movement was also provided, as well as presentations on the educational challenge of Paediatric Virology as a new subspecialty of Paediatrics. This review highlights selected lectures and discussions of the workshop.

Enterovirus 71 infection and vaccines

Hand, foot and mouth disease (HFMD) is a highly contagious viral infection affecting young children during the spring to fall seasons. Recently, serious outbreaks of HFMD were reported frequently in the Asia-Pacific region, including China and Korea. The symptoms of HFMD are usually mild, comprising fever, loss of appetite, and a rash with blisters, which do not need specific treatment. However, there are uncommon neurological or cardiac complications such as meningitis and acute flaccid paralysis that can be fatal. HFMD is most commonly caused by infection with coxsackievirus A16, and secondly by enterovirus 71 (EV71). Many other strains of coxsackievirus and enterovirus can also cause HFMD. Importantly, HFMD caused by EV71 tends to be associated with fatal complications. Therefore, there is an urgent need to protect against EV71 infection. Development of vaccines against EV71 would be the most effective approach to prevent EV71 outbreaks. Here, we summarize EV71 infection and development of vaccines, focusing on current scientific and clinical progress.

Viral exanthems: An update on laboratory testing of the adult patient

Although classic viral exanthems of childhood are well described, they are rarely differentiated in adults. Laboratory techniques for viral identification have advanced without substantial literature to suggest how a dermatologist ought to conduct a cost-effective and diagnostic viral panel. Certain clinical features such as petechiae, vesicles, and dusky macular or morbilliform exanthems point strongly toward a viral exanthem. Differentiation of drug and viral causes of morbilliform eruptions has proven difficult. It is possible that with further diagnostic refinement that unnecessary and fruitless workups of an exanthem and unneeded discontinuation of drugs can be avoided. We review viral exanthems based on clinical features and discuss the available and optimal laboratory techniques to assist the dermatologist in a targeted workup.

Yeast-produced recombinant virus-like particles of coxsackievirus A6 elicited protective antibodies in mice

Coxsackievirus A6 (CA6) has recently emerged as the predominant pathogen of hand, foot and mouth disease (HFMD), causing significant morbidity in children and adults. The increasing prevalence of CA6 infection and its associated disease burden underscore the need for effective CA6 vaccines. However, CA6 grows poorly in cultured cells, making it difficult to develop inactivated whole-virus or live attenuated vaccines. Here we report the development of a recombinant virus-like particle (VLP) based CA6 vaccine. CA6 VLPs were produced in Pichia pastoris yeast transformed with a vector encoding both P1 and 3CD proteins of CA6. Immunization with CA6 VLPs elicited CA6-specific serum antibodies in mice. Passive transfer of anti-VLP antisera protected recipient mice against lethal CA6 challenge. Collectively, these results demonstrate that CA6 VLPs represent a viable CA6 vaccine candidate which warrants further preclinical and clinical development.

Genomic features of coxsackievirus A6 correlate with herpangina and hand, foot and mouth disease

Aim: To study the genomic factors of coxsackievirus A6 (CVA6) correlated with herpangina and hand, foot and mouth disease (HFMD). Materials & methods: Complete genome of CVA6 strains and HFMD causing enteroviruses were enrolled for genomic comparisons. Results: Recombinations in the nonstructural P2-P3 region appeared to correlate with HFMD causing pathogenicity. Among nonrecombinant CVA6 strains, a markedly nucleotide diversity in 3C-3UTR was observed between herpangina and HFMD causing CVA6. Synonymous mutations take an important role in the evolution of CVA6 3C-3UTR region, as limited amino acid variations were resulted from the high nucleotide diversity. Key amino acid mutations at positions 168–170 of 3D protein were correlated with the differences in viral pathogenicities. Conclusion: These findings provide insights into viral genomic features correlated with CVA6 pathogenicities.

A literature review and case report of hand, foot and mouth disease in an immunocompetent adult

Background

To report an uncommon case of hand, foot and mouth disease, (HFMD) in an immunocompetent adult; a highly infectious disease, characterized by the appearance of vesicles on the mouth, hands and feet, associated with coxsackieviruses and enteroviruses; including a literature review.

Case report

A 23 year Caucasian male with no medical or surgical history, no allergies, was not taking any medication and smoked ten cigarettes a day, suffering from discomfort in the oral cavity; itching, burning and pain when swallowing associated with small erythematous lesions located on the hard palate, and small ulcers in tonsillar pillars and right buccal mucosa. Mild fever of 37.8 °C and general malaise. The patient reported he had had contact with a child diagnosed with HFMD. From his background and symptoms, the patient was diagnosed with HFMD. Following symptomatic treatment, the symptoms remitted in 7 days.

Methods

A literature review in MEDLINE (PubMed). The inclusion criteria were for studies on humans over the last 5 years, using the keywords HFMD.

Results

We found 925 articles, which were subsequently reduced to 52 documents after applying the inclusion criteria. Maculopapular lesions were found on hands and feet.

Conclusions

Dentists may have a key role diagnosing the disease. A surveillance system to predict future outbreaks, encourage early diagnosis, put appropriate public health measures in place and research vaccine development is vitally important in order to control the disease.

Immunological and biochemical characterizations of coxsackievirus A6 and A10 viral particles

Childhood exanthema caused by different serotypes of coxsackievirus (CV-A) and enterovirus A71 (EV-A71) has become a serious global health problem; it is commonly known as hand, foot, and mouth disease (HFMD). Current EV-A71 vaccine clinical trials have demonstrated that human antibody responses generated by EV-A71 vaccinations do not cross-neutralize coxsackievirus A16 (CV-A16). An effective multivalent HFMD vaccine is urgently needed. From molecular epidemiological studies in Southeast Asia, CV-A6 and CV-A10 are commonly found in HFMD outbreaks. In this study, CV-A6 and CV-A10 were individually cultured in rhabdomyosarcoma (RD) cells grown in medium containing serum, harvested and concentrated. In viral downstream purification, two viral fractions were separated by sucrose gradient zonal ultracentrifugation and detected using a SDS-PAGE analysis and a virus infectivity assay. These two viral fractions were formalin-inactivated, and only the infectious particle fraction was found to be capable of inducing CV-A serotype-specific neutralizing antibody responses in animal immunogenicity studies. These mouse and rabbit antisera also failed to cross-neutralize EV-A71 and CV-A16 infections. Only a combination of formalin-inactivated EV-A71, CV-A6, CV-A10 and CV-A16 multivalent vaccine candidates elicited cross-neutralizing antibody responses in both mouse and rabbit immunogenicity studies. The current results certainly provide important information for multivalent HFMD vaccine development.

Dual Kidney Transplantation From Pediatric Donors to Adult Recipients

BACKGROUND

The organ shortage is a global problem. A potential approach to expanding the deceased donor pool is to harvest organs from pediatric patients.

METHODS

Seven cases of dual kidney transplantation from pediatric donors to adult recipients were performed between 2012 and 2014 in our center. The proximal end of the donor aorta (AO) was anastomosed to the right common iliac artery or external artery. The proximal end of the donor inferior vena cava (IVC) was anastomosed to the right external iliac vein. Recipients received basiliximab or antithymocyte globulin as induction therapy, followed by tacrolimus, mycophenolate mofetil, and prednisone. Prophylactic anticoagulation was not universal in our study.

RESULTS

During the 21-month study period, both patient and graft survivals were 100%. No patient showed thrombotic complications. Complications included an acute rejection episode in 1 patient, urine leakage in 2, and anticoagulation related hemorrhage in 1. All recipients had excellent graft function with normal serum creatinine ranging from 0.49 to 1.45 mg/dL and estimated glomerular filtration rate ranging from 56.89 to 145.27 mL/min/1.73 m(2).

CONCLUSIONS

Dual kidney transplantation from pediatric donors to adult recipients is a promising way to expand the donor pool. Using the proximal end of the AO/IVC for anastomosis brings satisfactory results.

Unusual skin manifestation of hand, foot and mouth disease associated with coxsackievirus A6: cases report

Background

Hand, food, and mouth disease (HFMD) is a highly contagious disease caused by enteroviruses infection. It is a health problem in young children under 5 years of age worldwide. The common causative agents are coxsackievirus A 16 (CA16) and enterovirus 71 (EV71). In recent years, coxsackievirus A6 (CA6) has emerged to be one of the major etiologic agents of HFMD worldwide including in Thailand.

Case description

We reported cases with unusual skin manifestations of CA6-associated HFMD such as widespread severe cutaneous eruption, large vesicles (varicelliform), purpuric-like lesions or Gianotti–Crosti like eruptions.

Discussion and evaluation

Molecular characterization of the CA6 strains from those patients found that all were clustered in the same group of CA6 that are currently circulating in Thailand.

Conclusions

Clinicians need to be aware of the expanded range of cutaneous findings in CA6-associated HFMD in order to properly consider the diagnosis, management and prevention.

Hand, foot and mouth disease - a short case report

Hand, foot and mouth disease, that was once considered a disease of cattle, has been emerging as a common human childhood disease in the last few years. It is a viral disease characterized by a brief febrile illness and typical vesicular rashes. In rare cases, patients may also develop neurological complications. This report describes a case of hand, foot and mouth disease, presented with typical clinical features in the South Indian region.

Key words:Hand, foot and mouth disease, viral lesions, blisters.

The effect of meteorological variables on the transmission of hand, foot and mouth disease in four major cities of shanxi province, China: a time series data analysis (2009-2013)

Increased incidence of hand, foot and mouth disease (HFMD) has been recognized as a critical challenge to communicable disease control and public health response. This study aimed to quantify the association between climate variation and notified cases of HFMD in selected cities of Shanxi Province, and to provide evidence for disease control and prevention. Meteorological variables and HFMD cases data in 4 major cities (Datong, Taiyuan, Changzhi and Yuncheng) of Shanxi province, China, were obtained from the China Meteorology Administration and China CDC respectively over the period 1 January 2009 to 31 December 2013. Correlations analyses and Seasonal Autoregressive Integrated Moving Average (SARIMA) models were used to identify and quantify the relationship between the meteorological variables and HFMD. HFMD incidence varied seasonally with the majority of cases in the 4 cities occurring from May to July. Temperatures could play important roles in the incidence of HFMD in these regions. The SARIMA models indicate that a 1° C rise in average, maximum and minimum temperatures may lead to a similar relative increase in the number of cases in the 4 cities. The lag times for the effects of temperatures were identified in Taiyuan, Changzhi and Yuncheng. The numbers of cases were positively associated with average and minimum temperatures at a lag of 1 week in Taiyuan, Changzhi and Yuncheng, and with maximum temperature at a lag of 2 weeks in Yuncheng. Positive association between the temperature and HFMD has been identified from the 4 cities in Shanxi Province, although the role of weather variables on the transmission of HFMD varied in the 4 cities. Relevant prevention measures and public health action are required to reduce future risks of climate change with consideration of local climatic conditions.

Understanding of the impact of weather variables on HFMD transmission remains limited due to various local climatic conditions, socioeconomic status and demographic characteristics in different regions. This study provides quantitative evidence that the incidence of HFMD cases was significantly associated with temperature in Shanxi Province, North China. The delayed effects of weather variables on HFMD dictate different public health responses in 4 major cities in Shanxi Province. The results may provide a direction for local community and health authorities to perform public health actions, and the SARIMA models are helpful in the prediction of epidemics, determination of high-risk areas and susceptible populations, allocation of health resources, and the formulation of relevant prevention strategies. In order to reduce future risks of climatic variations on HFMD epidemics, similar studies in other geographical areas are needed, together with a longer study period to enable trend analysis which takes into consideration local weather conditions and demographic characteristics.

Disseminated coxsackievirus A6 affecting children with atopic dermatitis

Coxsackievirus A6 (CV-A6) is an emerging pathogen that has in recent years been associated with atypical hand, foot and mouth disease. This manifests as a generalized papular or vesicular eruption, which may be associated with fever and systemic disturbance. We report a series of six children presenting to a single centre in the UK with disseminated CV-A6 infection on a background of atopic dermatitis (AD). Our patients exhibited a widespread papular or vesicular eruption in association with exacerbation of AD. Several of our cases mimicked eczema herpeticum, but the extent was more generalized, and individual lesions were discrete rather than clustered and were less circumscribed in character. This series highlights that CV-A6 infection may be encountered in the UK, and should be considered in the differential diagnosis of an acute exacerbation of AD, particularly in children.

Unilateral acute maculopathy associated with adult onset hand, foot and mouth disease: case report and review of literature

Background

Acute maculopathy is a rare condition of unknown aetiology and Coxsackie virus is known to be associated with this macular chorioretinitis.

Findings

We report a case of acute unilateral maculopathy in a 35-year-old woman with concurrent hand foot and mouth disease. Furthermore, we display multimodal imaging (colour fundus photographs, autofluorescence, spectral domain ocular coherence tomography, fluorescein angiography and indocyanine green angiography) charting the course of the disease. The source of the virus was thought to be the patient's child. Empirical treatment with oral corticosteroids was commenced and the inflammation resolved, leaving a residual macular scar.

Conclusions

We present this case combined with the review of literature of adult onset Coxsackie-virus-associated retinitis. This case reiterates the fact that Coxsackie virus is an uncommon but important consideration in the differential diagnosis of chorioretinitis and posterior uveitis with atypical retinopathy.

A study of spatiotemporal delay in hand, foot and mouth disease in response to weather variations based on SVD: a case study in Shandong Province, China

Background

A large number of hand, foot and mouth disease (HFMD) outbreaks was reported during 2008 in China. However, little is known about the effects of meteorological conditions on different temporal and spatial scales on HFMD incidence in children. The aim of this study was to explore the relationship between meteorological data on various temporal and spatial scales and HFMD incidence among children in Shandong Province, China.

Methods

The association between weekly HFMD cases and meteorological data on different temporal and spatial scales in Shandong Province from May 2008 to July 2008 and September 2008 to October 2008 was analyzed, using buffer analysis and the singular value decomposition method.

Results

Wind speed within a 50-km buffer circle of counties in Shandong Province with two-week lag and RH within a 10-km buffer circle of counties with eight-week lag were significantly associated with HFMD incidence. We found a positive correlation between wind speed within the 50-km buffer circle in the prior two weeks and wind speed within the province in the prior one week.

Conclusions

This study revealed strong associations between HFMD incidence in children and wind speed and RH. Thus, meteorological anomalies in the prior two or eight weeks could be used as a valid tool for detecting anomalies during the peak periods of infectious disease.

An atypical course of coxsackievirus A6 associated hand, foot and mouth disease in extremely low birth weight preterm twins

The incidence of coxsackievirus A6 (CV-A6) associated hand, foot and mouth disease (HFMD) has reportedly increased since 2008 with sometimes severe complications. We here describe an atypical course of CV-A6-associated HFMD in extremely low birth weight twins. The CV-A6-strains are genetically closely related to international strains isolated from HFMD outbreaks.