Human enterovirus 71 strains in the background population and in hospital patients in Finland

Pleconaril and ribavirin in new-onset type 1 diabetes: a phase 2 randomized trial

Previous studies showed a low-grade enterovirus infection in the pancreatic islets of patients with newly diagnosed type 1 diabetes (T1D). In the Diabetes Virus Detection (DiViD) Intervention, a phase 2, placebo-controlled, randomized, parallel group, double-blind trial, 96 children and adolescents (aged 6-15 years) with new-onset T1D received antiviral treatment with pleconaril and ribavirin (n = 47) or placebo (n = 49) for 6 months, with the aim of preserving β cell function. The primary endpoint was the mean stimulated C-peptide area under the curve (AUC) 12 months after the initiation of treatment (less than 3 weeks after diagnosis) using a mixed linear model. The model used longitudinal log-transformed serum C-peptide AUCs at baseline, at 3 months, 6 months and 1 year. The primary endpoint was met with the serum C-peptide AUC being higher in the pleconaril and ribavirin treatment group compared to the placebo group at 12 months (average marginal effect = 0.057 in the linear mixed model; 95% confidence interval = 0.004-0.11, P = 0.037). The treatment was well tolerated. The results show that antiviral treatment may preserve residual insulin production in children and adolescent with new-onset T1D. This provides a rationale for further evaluating antiviral strategies in the prevention and treatment of T1D. European Union Drug Regulating Authorities Clinical Trials identifier: 2015-003350-41 .

Seroprevalence of coxsackievirus A6 and enterovirus A71 infection in humans: a systematic review and meta-analysis

Hand, foot, and mouth disease (HFMD) is a common infectious disease in children. Enterovirus A71 (EV-A71) is one of the main pathogens, and coxsackievirus A6 (CVA6) has gradually become the dominant pathogen of HFMD in recent years. This study was conducted mainly to assess the serological prevalence of EV-A71 and CVA6 antibodies in people of different ages, sexes, and regions through a systematic review and meta-analysis. A comprehensive study was performed based on the EV-A71 and CVA6 serological literature published before May 2022. Heterogeneity analysis (Cochrane's Q test and the I² statistic) and random effect models were adopted. Subgroup and meta-regression analyses were used to identify potential sources of heterogeneity in the data, and all analysis was performed using STATA version 16.0. This study included 71 studies involving 55,176 people from 13 countries that met the inclusion criteria. The serological prevalence of EV-A71 antibody in different studies was 4.31-88.8%, and that of CVA6 antibody was 40.8-80.9%. Meta-analysis results showed that the serum positive rate for EV-A71 antibody was 45.9% (95% CI: 37.6-54.1%). The rate in the Chinese population was 47.8% (95% CI: 42.4-53.2%), and in the other countries, it was 38% (95% CI: 23-55%). The serum positive rate for CVA6 antibody was 58.3% (95% CI: 46.5-70.2%). The rate in the Chinese population was 49.1% (95% CI: 38.3-59.9%), and in the other countries, it was 68% (95% CI: 51-83%). Subgroup analysis was also conducted. The seroprevalence of EV-A71 and CVA6 antibodies is related to age rather than gender or region. The rates of EV-A71 and CVA6 seropositivity are considerably lower in children younger than five years of age. However, the rates gradually increase with age. The findings of this study suggest that children under five years of age may be susceptible to EV-A71 and CVA6. Thus, safety education and vaccination should be strengthened accordingly. This study provides a basis for understanding the risk factors for EV-A71 and CVA6 infection in China and for deciding how to formulate standard preventive measures to prevent the spread of the virus.

Eukaryotic viruses in the fecal virome at the onset of type 1 diabetes: A study from four geographically distant African and Asian countries

OBJECTIVES

Studies of the fecal virome in type 1 diabetes (T1D) have been limited to populations of Europe and the United States. We therefore sought to characterize the stool virome in children after onset of T1D and in matched control subjects from four geographically distant African and Asian countries.

METHODS

Samples of stool were collected from 73 children and adolescents shortly after T1D onset (Azerbaijan 19, Jordan 20, Nigeria 14, Sudan 20) and 105 matched control subjects of similar age and locale. Metagenomic sequencing of the DNA and RNA virome was performed, and virus positivity was defined as more than 0.001% of reads of the sample. Selected viruses were also quantified using real-time PCR. Conditional logistic regression was used to model associations with eukaryotic virus positivity.

RESULTS

Signals of 387 different viral species were detected; at least one eukaryotic virus was detected in 71% case and 65% control samples. Neither of observed eukaryotic virus species or genera differed in frequency between children with T1D and controls. There was a suggestive association of the total count of different viral genera per sample between cases (1.45 genera) and controls (1.10 genera, OR 1.24, 95%CI 0.98-1.57), and an unplanned subanalysis suggested marginally more frequent endogenous retrovirus signal in cases (in 28.8% vs. in 8.6% controls, OR = 4.55, 95%CI 1.72-12).

CONCLUSIONS

No clear and consistent association with T1D was observed in the fecal viromes from four distant non-European populations. The finding of borderline associations of human endogenous retroviruses merits further exploration.

Association of Picornavirus Infections With Acute Otitis Media in a Prospective Birth Cohort Study

BACKGROUND

Human rhinoviruses (HRVs), human enteroviruses (HEVs) and human parechoviruses (HPeVs) have been linked to acute otitis media (AOM). We evaluated this association in a prospective birth cohort setting.

METHODS

A total of 324 healthy infants were followed up from birth to age 3 years. Nasal swab samples were collected at age 3, 6, 12, 18, 24, and 36 months and screened for HRV and HEV using real-time reverse-transcription quantitative polymerase chain reaction. Stool samples were collected monthly and analyzed for HRV, HEV, and HPeV. AOM episodes diagnosed by physicians were reported by parents in a diary. The association of viruses with AOM was analyzed using generalized estimation equations, and their relative contributions using population-attributable risk percentages.

RESULTS

A clear association was found between AOM episodes and simultaneous detection of HEV (adjusted odds ratio for the detection of virus in stools, 2.04; 95% confidence interval, 1.06-3.91) and HRV (1.54; 1.04-2.30). HPeV showed a similar, yet nonsignificant trend (adjusted odds ratio, 1.44; 95% confidence interval, .81-2.56). HRV and HEV showed higher population-attributable risk percentages (25% and 20%) than HPeV (11%).

CONCLUSIONS

HEVs and HRVs may contribute to the development of AOM in a relatively large proportion of cases.

Genetic Adaptation of Coxsackievirus B1 during Persistent Infection in Pancreatic Cells

Coxsackie B (CVB) viruses have been associated with type 1 diabetes. We have recently observed that CVB1 was linked to the initiation of the autoimmune process leading to type 1 diabetes in Finnish children. Viral persistency in the pancreas is currently considered as one possible mechanism. In the current study persistent infection was established in pancreatic ductal and beta cell lines (PANC-1 and 1.1B4) using four different CVB1 strains, including the prototype strain and three clinical isolates. We sequenced 5′ untranslated region (UTR) and regions coding for structural and non-structural proteins and the second single open reading frame (ORF) protein of all persisting CVB1 strains using next generation sequencing to identify mutations that are common for all of these strains. One mutation, K257R in VP1, was found from all persisting CVB1 strains. The mutations were mainly accumulated in viral structural proteins, especially at BC, DE, EF loops and C-terminus of viral capsid protein 1 (VP1), the puff region of VP2, the knob region of VP3 and infection-enhancing epitope of VP4. This showed that the capsid region of the viruses sustains various changes during persistency some of which could be hallmark(s) of persistency.

Differential Detection of Encapsidated versus Unencapsidated Enterovirus RNA in Samples Containing Pancreatic Enzymes-Relevance for Diabetes Studies

Using immunohistochemistry, enterovirus capsid proteins were demonstrated in pancreatic islets of patients with type 1 diabetes. Virus proteins are mainly located in beta cells, supporting the hypothesis that enterovirus infections may contribute to the pathogenesis of type 1 diabetes. In samples of pancreatic tissue, enterovirus RNA was also detected, but in extremely small quantities and in a smaller proportion of cases compared to the enteroviral protein. Difficulties in detecting viral RNA could be due to the very small number of infected cells, the possible activity of PCR inhibitors, and the presence—during persistent infection—of the viral genome in unencapsidated forms. The aim of this study was twofold: (a) to examine if enzymes or other compounds in pancreatic tissue could affect the molecular detection of encapsidated vs. unencapsidated enterovirus forms, and (b) to compare the sensitivity of RT-PCR methods used in different laboratories. Dilutions of encapsidated and unencapsidated virus were spiked into human pancreas homogenate and analyzed by RT-PCR. Incubation of pancreatic homogenate on wet ice for 20 h did not influence the detection of encapsidated virus. In contrast, a 15-min incubation on wet ice dramatically reduced detection of unencapsidated forms of virus. PCR inhibitors could not be found in pancreatic extract. The results show that components in the pancreas homogenate may selectively affect the detection of unencapsidated forms of enterovirus. This may lead to difficulties in diagnosing persisting enterovirus infection in the pancreas of patients with type 1 diabetes.

Eradication of persistent coxsackievirus B infection from a pancreatic cell line with clinically used antiviral drugs

BACKGROUND

Persistent enterovirus infections create a difficult therapeutic challenge in immunocompromised patients and may also contribute to the development of chronic diseases including type 1 diabetes, cardiomyopathies, post-polio syndrome and chronic fatigue syndrome.

OBJECTIVES

To study the ability of antiviral drugs to eradicate such infection in vitro to evalaute their potential in the treatments of these patients.

STUDY DESIGN

We set out to evaluate several licensed or clinically tested drugs which have shown some anti-enterovirus activity in previous studies for their ability to cure persistent infection established by two different coxsackievirus B1 strains in a pancreatic cell line (PANC-1 cells).

RESULTS

Among all tested drugs Enviroxime, Fluoxetine, concentrated human IgG product (Hizentra) and Pleconaril were able to eradicate persistent Coxsackievirus B1 infection. The effect Enviroxime, Hizentra and Pleconaril varied between the two virus strains.

CONCLUSIONS

The identified drugs are feasible candidates for clinical trials among patients with persistent coxsackievirus B infections or chronic enterovirus-associated diseases.

Viruses in Vietnamese Patients Presenting with Community-Acquired Sepsis of Unknown Cause

Community-acquired (CA) sepsis is a major public health problem worldwide, yet the etiology remains unknown for >50% of the patients. Here we applied metagenomic next-generation sequencing (mNGS) to characterize the human virome in 492 clinical samples (384 sera, 92 pooled nasal and throat swabs, 10 stools, and 6 cerebrospinal fluid samples) from 386 patients (213 adults and 173 children) presenting with CA sepsis who were recruited from 6 hospitals across Vietnam between 2013 and 2015. Specific monoplex PCRs were used subsequently to confirm the presence of viral sequences detected by mNGS. We found sequences related to 47 viral species belonging to 21 families in 358 of 386 (93%) patients, including viruses known to cause human infections. After PCR confirmation, human viruses were found in 52 of 386 patients (13.4%); picornavirus (enteroviruses [n = 14], rhinovirus [n = 5], and parechovirus [n = 2]), hepatitis B virus (n = 10), cytomegalovirus (n = 9), Epstein-Barr virus (n = 5), and rotavirus A (n = 3) were the most common viruses detected. Recently discovered viruses were also found (gemycircularvirus [n = 5] and WU polyomavirus, Saffold virus, salivirus, cyclovirus-VN, and human pegivirus 2 [HPgV2] [n, 1 each]), adding to the growing literature about the geographic distribution of these novel viruses. Notably, sequences related to numerous viruses not previously reported in human tissues were also detected. To summarize, we identified 21 viral species known to be infectious to humans in 52 of 386 (13.4%) patients presenting with CA sepsis of unknown cause. The study, however, cannot directly impute sepsis causation to the viruses identified. The results highlight the fact that it remains a challenge to establish the causative agents in CA sepsis patients, especially in tropical settings such as Vietnam.

Rhinoviruses in infancy and risk of immunoglobulin E sensitization

Previous data about the role of viruses in the development of allergic immunoglobulin E (IgE) sensitization are contradictory. The aim of this study was to determine the possible associations between exposure to different viruses (rhinovirus, enterovirus, norovirus, and parechovirus) during the first year of life and IgE sensitization. Viruses were analyzed from stool samples collected monthly from infants participating in a prospective birth cohort study. From that study, 244 IgE sensitized case children and 244 nonsensitized control children were identified based on their allergen-specific IgE antibody levels at the age of 6, 18, and 36 months. Stool samples (n = 4576) from the case and control children were screened for the presence of rhinovirus, enterovirus, norovirus, and parechovirus RNA by reverse transcription quantitative polymerase chain reaction. The study showed that rhinovirus was the most prevalent virus detected, present in 921 (20%) samples. None of the viruses were associated with IgE sensitization in the full cohort but after stratifying by sex, the number of rhinovirus positive samples was inversely associated with IgE sensitization in boys (odds ratio [OR]: 0.81; 95% confidence interval [CI]: 0.69-0.94; P = 0.006). There was also a temporal relation between rhinoviruses and IgE sensitization, as rhinovirus exposure during the first 6 months of life was associated with a reduced risk of subsequent IgE sensitization in boys (OR: 0.76; 95% CI: 0.6-0.94; P = 0.016). In conclusion, early exposure to rhinoviruses was inversely associated with IgE sensitization but this protective association was restricted to boys.

Enterovirus as trigger of coeliac disease: nested case-control study within prospective birth cohort

OBJECTIVE

To determine whether infection with human enterovirus or adenovirus, both common intestinal viruses, predicts development of coeliac disease.

DESIGN

Case-control study nested within Norwegian birth cohort recruited between 2001 and 2007 and followed to September 2016.

SETTING

Norwegian population.

PARTICIPANTS

Children carrying the HLA genotype DR4-DQ8/DR3-DQ2 conferring increased risk of coeliac disease.

EXPOSURES

Enterovirus and adenovirus detected using real time polymerase chain reaction in monthly stool samples from age 3 to 36 months.

MAIN OUTCOME MEASURE

Coeliac disease diagnosed according to standard criteria. Coeliac disease antibodies were tested in blood samples taken at age 3, 6, 9, and 12 months and then annually. Adjusted odds ratios from mixed effects logistic regression model were used to assess the relation between viral infections before development of coeliac disease antibodies and coeliac disease.

RESULTS

Among 220 children, and after a mean of 9.9 (SD 1.6) years, 25 children were diagnosed as having coeliac disease after screening and were matched to two controls each. Enterovirus was found in 370 (17%) of 2135 samples and was significantly more frequent in samples collected before development of coeliac disease antibodies in cases than in controls (adjusted odds ratio 1.49, 95% confidence interval 1.07 to 2.06; P=0.02). The association was restricted to infections after introduction of gluten. High quantity samples (>100 000 copies/μL) (adjusted odds ratio 2.11, 1.24 to 3.60; P=0.01) and long lasting infections (>2 months) (2.16, 1.16 to 4.04; P=0.02) gave higher risk estimates. Both the commonly detected enterovirus species Enterovirus A and Enterovirus B were significantly associated with coeliac disease. The association was not found for infections during or after development of coeliac disease antibodies. Adenovirus was not associated with coeliac disease.

CONCLUSIONS

In this longitudinal study, a higher frequency of enterovirus, but not adenovirus, during early childhood was associated with later coeliac disease. The finding adds new information on the role of viral infections in the aetiology of coeliac disease.

Virus genotyping by massive parallel amplicon sequencing: adenovirus and enterovirus in the Norwegian MIDIA study

OBJECTIVES

Direct genotyping of adenovirus or enterovirus from clinical material using polymerase chain reaction (PCR) followed by Sanger sequencing is often difficult due to the presence of multiple virus types in a sample, or due to varying efficacy of PCR amplifying the capsid gene on the background of foreign nucleic acids. Here we present a simple protocol for virus genotyping using massive parallel amplicon sequencing.

METHODS

The protocol utilized a set of 16 tailed degenerate primers flanking the seventh hypervariable region of the adenovirus hexon gene and 9 tailed degenerate primers targeted to the proximal portion of the enterovirus VP1 gene. Subsequent addition of dual indices enabled simultaneous sequencing of 384 different samples on an Illumina MiSeq instrument. Downstream bioinformatic analysis was based on remapping to a set of references representative of the presently known repertoire of virus types.

RESULTS

After validation with known virus types, the sequencing method was applied on 301 adenovirus-positive samples and 350 enterovirus-positive samples from a longitudinally collected series of stools from 83 children aged 3 to 36 months. We detected 7 different adenovirus types and 27 different enterovirus types. There were 37 (6.2%) samples containing more than one genotype of the same viral genus. At least one dual infection was experienced by 23 of 83 (28%) of the children observed over the 3 years' observation period.

CONCLUSIONS

Amplicon sequencing with a multiplex set of degenerate primers seems to be a rapid and reliable technical solution for genotyping of large collections of samples where simultaneous infections with multiple strains can be expected.

Prediction of Protection against Asian Enterovirus 71 Outbreak Strains by Cross-neutralizing Capacity of Serum from Dutch Donors, The Netherlands

Herd immunity induced by locally circulating strains could provide protection against introduction of new strains.

Outbreaks of human enterovirus 71 (EV-71) in Asia are related to high illness and death rates among children. To gain insight into the potential threat for the population of Europe, we determined the neutralizing activity in intravenous immunoglobulin (IVIg) batches and individual serum samples from donors in the Netherlands against EV-71 strains isolated in Europe and in Asia. All IVIg batches and 41%, 79%, and 65% of serum samples from children ≤5 years of age, women of childbearing age, and HIV-positive men, respectively, showed high neutralizing activity against a Dutch C1 strain, confirming widespread circulation of EV-71 in the Netherlands. Asian B3–4 and C4 strains were efficiently cross-neutralized, predicting possible protection against extensive circulation and associated outbreaks of those types in Europe. However, C2 and C5 strains that had few mutations in the capsid region consistently escaped neutralization, emphasizing the importance of monitoring antigenic diversity among circulating EV-71 strains.

Enterovirus-associated changes in blood transcriptomic profiles of children with genetic susceptibility to type 1 diabetes

AIMS/HYPOTHESIS

Enterovirus infections have been associated with the development of type 1 diabetes in multiple studies, but little is known about enterovirus-induced responses in children at risk for developing type 1 diabetes. Our aim was to use genome-wide transcriptomics data to characterise enterovirus-associated changes in whole-blood samples from children with genetic susceptibility to type 1 diabetes.

METHODS

Longitudinal whole-blood samples (356 samples in total) collected from 28 pairs of children at increased risk for developing type 1 diabetes were screened for the presence of enterovirus RNA. Seven of these samples were detected as enterovirus-positive, each of them collected from a different child, and transcriptomics data from these children were analysed to understand the individual-level responses associated with enterovirus infections. Transcript clusters with peaking or dropping expression at the time of enterovirus positivity were selected as the enterovirus-associated signals.

RESULTS

Strong signs of activation of an interferon response were detected in four children at enterovirus positivity, while transcriptomic changes in the other three children indicated activation of adaptive immune responses. Additionally, a large proportion of the enterovirus-associated changes were specific to individuals. An enterovirus-induced signature was built using 339 genes peaking at enterovirus positivity in four of the children, and 77 of these genes were also upregulated in human peripheral blood mononuclear cells infected in vitro with different enteroviruses. These genes separated the four enterovirus-positive samples clearly from the remaining 352 blood samples analysed.

CONCLUSIONS/INTERPRETATION

We have, for the first time, identified enterovirus-associated transcriptomic profiles in whole-blood samples from children with genetic susceptibility to type 1 diabetes. Our results provide a starting point for understanding the individual responses to enterovirus infections in blood and their potential connection to the development of type 1 diabetes.

DATA AVAILABILITY

The datasets analysed during the current study are included in this published article and its supplementary information files ( www.btk.fi/research/computational-biomedicine/1234-2 ) or are available from the Gene Expression Omnibus (GEO) repository (accession GSE30211).

A Coxsackievirus B vaccine protects against virus-induced diabetes in an experimental mouse model of type 1 diabetes

AIMS/HYPOTHESIS

Epidemiological studies suggest a role for Coxsackievirus B (CVB) serotypes in the pathogenesis of type 1 diabetes, but their actual contribution remains elusive. In the present study, we have produced a CVB1 vaccine to test whether vaccination against CVBs can prevent virus-induced diabetes in an experimental model.

METHODS

NOD and SOCS1-tg mice were vaccinated three times with either a formalin-fixed non-adjuvanted CVB1 vaccine or a buffer control. Serum was collected for measurement of neutralising antibodies using a virus neutralisation assay. Vaccinated and buffer-treated mice were infected with CVB1. Viraemia and viral replication in the pancreas were measured using standard plaque assay and PCR. The development of diabetes was monitored by blood glucose measurements. Histological analysis and immunostaining for viral capsid protein 1 (VP1), insulin and glucagon in formalin-fixed paraffin embedded pancreas was performed.

RESULTS

The CVB1 vaccine induced strong neutralising antibody responses and protected against viraemia and the dissemination of virus to the pancreas in both NOD mice (n = 8) and SOCS1-tg mice (n = 7). Conversely, 100% of the buffer-treated NOD and SOCS1-tg mice were viraemic on day 3 post infection. Furthermore, half (3/6) of the buffer-treated SOCS1-tg mice developed diabetes upon infection with CVB1, with a loss of the insulin-positive beta cells and damage to the exocrine pancreas. In contrast, all (7/7) vaccinated SOCS1-tg mice were protected from virus-induced diabetes and showed no signs of beta cell loss or pancreas destruction (p < 0.05).

CONCLUSIONS/INTERPRETATION

CVB1 vaccine can efficiently protect against both CVB1 infection and CVB1-induced diabetes. This preclinical proof of concept study provides a base for further studies aimed at developing a vaccine for use in elucidating the role of enteroviruses in human type 1 diabetes.

Virome Sequencing of Stool Samples

Next-generation sequencing has opened avenues to studying complex populations such as the bacteriome (all bacteria), mycobiome (all fungi), and virome (all viruses in a given sample). Viromes are less often investigated as compared to bacteriomes. The reasons are mostly methodological: because no common pan-viral sequence signature exists, metagenomic sequencing remains the only option. This brings about the need of laborious virus enrichment, multiple signal amplification steps with virtually no possibility of interim quality control, and complicated bioinformatic analysis of the ensuing sequence data. Nevertheless, over the past decade virome sequencing has been enormously successful in identifying new agents in human and animal diseases, and in characterizing viruses in various ecological niches. Recently, virome sequencing has been also employed in studies of non-infectious diseases, which has brought about new challenges of sensitivity, costs, and reproducibility in testing of large sets of samples. Here, we present a detailed protocol that has been utilized in virome studies where hundreds of samples had to be reliably tested in order to assess the association of the stool virome with susceptibility to type 1 diabetes, a non-infectious autoimmune disease.

Prevalence of enteroviruses in healthy populations and excretion of pathogens in patients with hand, foot, and mouth disease in a highly endemic area of southwest China

Etiological carriers and the excretion of the pathogens causing hand, foot, and mouth disease (HFMD) in healthy persons, patients, and asymptomatic persons infected with HFMD as ongoing infection sources may play an important role in perpetuating and spreading epidemics of HFMD. The aims of this study were to determine the carrier status of EV-A71 and CV-A16 in healthy populations, as well as the duration of EV-A71 and CV-A16 shedding in the stools of HFMD patients in an epidemic area of southwest China. A cross-sectional study and a follow-up study were conducted in three HFMD endemic counties of Yunnan Province. Six hundred sixty-seven healthy subjects were recruited to participate in the cross-sectional study, and two stool specimens were collected from each subject. Among the healthy subjects, 90 (13.5%) tested positive for viral isolation, but neither EV-A71 nor CV-A16 was detected in healthy individuals. Of the 150 patients with probable HFMD, 55.3% (83/150) tested positive for viral isolation with presented serotypes such as EV-A71 (51.81%, 43/83), CV-A16 (32.53%, 27/83), other EVs (13.25%, 11/83), and mixed EV-A71 and CV-A16 (2.41%, 2/83). The longest duration of EV-A71 and CV-A16 shedding in stool specimens from patients with HFMD was >46 days after onset. The positive rate of EV-A71 in the stool specimens of confirmed patients dropped to 50% by the end of the third week, and the same occurred with CV-A16 by the end of approximately the seventh week after onset. Although carriers of major causative agents of HFMD in healthy populations are fewer in number, the prolonged shedding of pathogens in patients with HFMD may serve as an important factor in perpetuating and spreading HFMD epidemics.

Detection of enteroviruses in stools precedes islet autoimmunity by several months: possible evidence for slowly operating mechanisms in virus-induced autoimmunity

AIMS/HYPOTHESIS

This case-control study was nested in a prospective birth cohort to evaluate whether the presence of enteroviruses in stools was associated with the appearance of islet autoimmunity in the Type 1 Diabetes Prediction and Prevention study in Finland.

METHODS

Altogether, 1673 longitudinal stool samples from 129 case children who turned positive for multiple islet autoantibodies and 3108 stool samples from 282 matched control children were screened for the presence of enterovirus RNA using RT-PCR. Viral genotype was detected by sequencing.

RESULTS

Case children had more enterovirus infections than control children (0.8 vs 0.6 infections per child). Time-dependent analysis indicated that this excess of infections occurred more than 1 year before the first detection of islet autoantibodies (6.3 vs 2.1 infections per 10 follow-up years). No such difference was seen in infections occurring less than 1 year before islet autoantibody seroconversion or after seroconversion. The most frequent enterovirus types included coxsackievirus A4 (28% of genotyped viruses), coxsackievirus A2 (14%) and coxsackievirus A16 (11%).

CONCLUSIONS/INTERPRETATION

The results suggest that enterovirus infections diagnosed by detecting viral RNA in stools are associated with the development of islet autoimmunity with a time lag of several months.

Human enterovirus and rhinovirus infections are associated with otitis media in a prospective birth cohort study

BACKGROUND

Human enteroviruses (HEVs) and rhinoviruses (HRVs) have been linked to acute otitis media (AOM).

OBJECTIVES

The present study evaluates the aforementioned association in a birth cohort setting.

STUDY DESIGN

The cohort included 286 healthy infants (191 boys) followed from birth up to the age of 2 years in the Type 1 Diabetes Prediction and Prevention study in Finland. Stool samples were collected monthly and analyzed for the presence of HRV and HEV RNA using RT-PCR. Clinical symptoms were recorded by a questionnaire every 3-6 months.

RESULTS

Altogether 610 AOM episodes were reported during the follow-up. 9.8% of the stool samples were positive for HRV and 6.8% for HEV. HRV positivity peaked at the age of 3-6 months declining gradually after this age, whereas HEV positivity peaked later, at the age of 12-24 months. The risk of AOM was increased in children who were HEV positive at least once at the age of 6-12 months (OR 2.2 [95%CI 1.1-4.2], P=0.023) or who were HRV positive at least once at the age of 18-24 months (OR 2.3 [95%CI 1.0-5.2], P=0.042). Having an older sibling, short breast-feeding and maternal smoking during pregnancy were also significantly associated with AOM.

CONCLUSIONS

HRV and HEV infections are frequent during the first months of life. The observed trend for increased risk of AOM in HRV and HEV positive children is in line with the results from hospital series suggesting that these viruses may play an independent role in the pathogenesis of AOM.

Relative sensitivity of immunohistochemistry, multiple reaction monitoring mass spectrometry, in situ hybridization and PCR to detect Coxsackievirus B1 in A549 cells

BACKGROUND

Enteroviruses (EVs) have been linked to the pathogenesis of several diseases and there is a collective need to develop improved methods for the detection of these viruses in tissue samples.

OBJECTIVES

This study evaluates the relative sensitivity of immunohistochemistry (IHC), proteomics, in situ hybridization (ISH) and RT-PCR to detect one common EV, Coxsackievirus B1 (CVB1), in acutely infected human A549 cells in vitro.

STUDY DESIGN

A549 cells were infected with CVB1 and diluted with uninfected A549 cells to produce a limited dilution series in which the proportion of infected cells ranged from 10(-1) to 10(-8). Analyses were carried out by several laboratories using IHC with different anti-EV antibodies, ISH with both ViewRNA and RNAScope systems, liquid chromatography multiple reaction monitoring mass spectrometry (LC/MRM/MS/MS), and two modifications of RT-PCR.

RESULTS

RT-PCR was the most sensitive method for EV detection yielding positive signals in the most diluted sample (10(-8)). LC/MRM/MS/MS detected viral peptides at dilutions as high as 10(-7). The sensitivity of IHC depended on the antibody used, and the most sensitive antibody (Dako clone 5D8/1) detected virus proteins at a dilution of 10(-6), while ISH detected the virus at dilutions of 10(-4).

CONCLUSIONS

All methods were able to detect CVB1 in infected A549 cells. RT-PCR was most sensitive followed by LC/MRM/MS/MS and then IHC. The results from this in vitro survey suggest that all methods are suitable tools for EV detection but that their differential sensitivities need to be considered when interpreting the results from such studies.

MicroRNA and Pathogenesis of Enterovirus Infection

There are no currently available specific antiviral therapies for non-polio Enterovirus infections. Although several vaccines have entered clinical trials, the efficacy requires further evaluation, particularly for cross-strain protective activity. Curing patients with viral infections is a public health problem due to antigen alterations and drug resistance caused by the high genomic mutation rate. To conquer these limits in the development of anti-Enterovirus treatments, a comprehensive understanding of the interactions between Enterovirus and host cells is urgently needed. MicroRNA (miRNA) constitutes the biggest family of gene regulators in mammalian cells and regulates almost a half of all human genes. The roles of miRNAs in Enterovirus pathogenesis have recently begun to be noted. In this review, we shed light on recent advances in the understanding of Enterovirus infection-modulated miRNAs. The impacts of altered host miRNAs on cellular processes, including immune escape, apoptosis, signal transduction, shutdown of host protein synthesis and viral replication, are discussed. Finally, miRNA-based medication provides a promising strategy for the development of antiviral therapy.

Epidemiologic and etiologic characteristics of hand, foot, and mouth disease in Chongqing, China between 2010 and 2013

Hand, foot, and mouth disease (HFMD) has become very common in children, with widespread occurrence across China. The aim of this study was to investigate the epidemiologic and etiologic characteristics of HFMD, including etiologic variations in Chongqing, China. An epidemiologic investigation was based on 3,472 patients who presented with HFMD manifestations and were admitted at the Children's Hospital of Chongqing Medical University between 2010 and 2013. Fecal specimens from 830 patients were analyzed by nested RT-PCR to identify the enterovirus pathogens, and the molecular characterization of HFMD was illustrated by phylogenetic tree analysis. The results of this study indicate that the peak of the HFMD epidemic in Chongqing between 2010 and 2013 occurred between April and July each year. The median age of onset was 2.24 years old, and children under the age of five accounted for 96.4% of all the HFMD cases; the male-to-female ratio was 1.89:1. Enterovirus 71 accounted for a major proportion of the isolated strains every year, including the majority (74%) of severe cases. However, the proportion of Coxsackie A (CV-A) 6 infections increased from 2.11% in 2010 to 16.36% in 2013, while the proportion of CV-A16 infections decreased from 31.23% in 2010 to 4.67% in 2013. Molecular epidemiologic study showed that all enterovirus 71 strains belonged to subgenotype C4a, whereas all CV-A16 strains belonged to genotype B1, including subgenotype B1a and subgenotype B1b.

Transmission patterns of human enterovirus 71 to, from and among European countries, 2003 to 2013

Enterovirus 71 (EV-71) is involved in epidemics of hand, foot, and mouth disease (HFMD) and has been reported to occur with severe neurological complications in eastern and south-east Asia. In other geographical areas, the transmission of this virus is poorly understood. We used large sequence datasets (of the gene encoding the viral protein 1, VP1) and a Bayesian phylogenetic approach to compare the molecular epidemiology and geographical spread patterns of EV-71 subgenogroups B4, B5, C1, C2, and C4 in Europe relative to other parts of the world. For the study, European countries considered were European Union (EU) Member States and Iceland, Norway and Switzerland. Viruses of the B4, B5, and C4 subgenogroups circulate mainly in eastern and south-east Asia. In Europe sporadic introductions of these subgenogroups are observed, however C1 and C2 viruses predominate. The phylogenies showed evidence of multiple events of spread involving C1 and C2 viruses within Europe since the mid-1990s. Two waves of sporadic C2 infections also occurred in 2010 and 2013. The 2007 Dutch outbreak caused by C2 and the occurrence of B5 and C4 infections in the EU between 2004 and 2013 arose while the circulation of C1 viruses was low. A transmission chain involving a C4 virus was traced from Japan to the EU and then further to Canada between 2001 and 2006. Recent events whereby spread of viruses have occurred from, to, and within Europe appear to be involved in the long term survival of EV-71, highlighting the need for enhanced surveillance of this virus.

Gut virome sequencing in children with early islet autoimmunity

OBJECTIVE

This study used next-generation sequencing (NGS) technologies to characterize the gut virome at the onset of islet autoimmunity.

RESEARCH DESIGN AND METHODS

We conducted a case-control study nested within the Finnish Diabetes Prediction and Prevention (DIPP) cohort. The stool virome in 19 case children, who turned islet autoantibody positive before the age of 2 years and later developed clinical type 1 diabetes, and 19 tightly matched control subjects was analyzed using NGS performed from stool samples collected 3, 6, and 9 months before the onset of islet autoimmunity. Human virus findings were verified using real-time PCR.

RESULTS

One or more human viruses were present in 10.4% and bacteriophages were in 54% of the samples. The virome composition showed no association with islet autoimmunity. NGS was less sensitive and specific than real-time PCR.

CONCLUSIONS

The present data suggest no dramatic changes in the gut virome shortly before the emergence of islet autoimmunity and emphasize the need of verification of mass sequencing results when viral exposure is assessed in association studies.

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

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

Enterovirus RNA in longitudinal blood samples and risk of islet autoimmunity in children with a high genetic risk of type 1 diabetes: the MIDIA study

AIMS/HYPOTHESIS

Only a few longitudinal molecular studies of enterovirus and islet autoimmunity have been reported, and positive results seem to be limited to Finland. We aimed to investigate an association between enterovirus RNA in blood and islet autoimmunity in the MIDIA study from Norway, a country which largely shares environmental and economic features with Finland.

METHODS

We analysed serial blood samples collected at ages 3, 6, and 9 months and then annually from 45 children who developed confirmed positivity for at least two autoantibodies (against insulin, GAD65 and IA-2) and 92 matched controls, all from a cohort of children with a single high-risk HLA-DQ-DR genotype. Enterovirus was tested in RNA extracted from frozen blood cell pellets, using real-time RT-PCR with stringent performance control.

RESULTS

Out of 807 blood samples, 72 (8.9%) were positive for enterovirus. There was no association between enterovirus RNA and islet autoimmunity in samples obtained strictly before (7.6% cases, 10.0% controls, OR 0.75 [95% CI 0.36, 1.57]), or strictly after the first detection of islet autoantibodies (10.5% case, 5.8% controls, OR 2.00 [95% CI 0.64, 6.27]). However, there was a tendency towards a higher frequency of enterovirus detection in the first islet autoantibody-positive sample (15.8%) compared with the corresponding time point in matched controls (3.2%, OR 8.7 [95% CI 0.97, 77]). Neither of these results was changed by adjusting for potential confounders, restricting to various time intervals or employing various definitions of enterovirus positivity.

CONCLUSIONS/INTERPRETATION

Positivity for enterovirus RNA in blood did not predict the later induction of islet autoantibodies, but enterovirus tended to be detected more often at the islet autoantibody seroconversion stage.

The variations of VP1 protein might be associated with nervous system symptoms caused by enterovirus 71 infection

Background

The VP1 protein of enterovirus 71 (EV71) is an important immunodominant protein which is responsible for host-receptor binding. Nevertheless, the relationship between VP1 and neurovirulence is still poorly understood. In this study, we investigated the relationship between mutation of VP1 and neurovirulent phenotype of EV71 infection.

Methods

One hundred and eighty-seven strains from Genbank were included, with a clear clinical background. They were divided into two groups, one with nervous system symptoms and one with no nervous system symptoms. After alignment, the significance of amino acid variation was determined by using the χ² test and a phylogenetic tree was constructed with MEGA software (version 5.1).

Results

We showed no significant difference in neurovirulence between genotype B and C. Interestingly, we found that variations of E145G/Q, E164D/K and T292N/K were associated with nervous system infection in genotype B. In the case of genotype C, the N31D mutation increased the risk for nervous complications, whereas I262V mutation decreased the risk of nervous complications. We used a 3D model of VP1 to demonstrate the potential molecular basis for EV71 nervous system tropism.

Conclusions

Distinct variations are shown to be associated with neurovirulent phenotype in the different genotype. Detection of variation in genotypes and subtypes may be important for the prediction of clinical outcomes.

Severe enterovirus type 71 nervous system infections in children in the Shanghai region of China: clinical manifestations and implications for prevention and care

BACKGROUND

Severe outbreaks of enterovirus 71 (EV71) have been on the rise in the Western Pacific region, including in China since 2007. We describe features of pediatric patients admitted with severe disease EV71 to a tertiary care hospital during the 2010 ongoing outbreak in the Shanghai region.

METHODS

The Shanghai EV71 outbreak was studied prospectively from January 2010 to December 2012. To be eligible, children had to be 1 month to <14 years of age, admitted with confirmed EV71 infection to Xinhua Hospital and have severe illness needing Pediatric Infectious Diseases Service care with symptoms/signs of high prolonged fever and/or very unwell general appearance and/or neurological findings but no underlying medical condition. Clinical, laboratory, treatment discharge and follow-up data were recorded and analyzed.

RESULTS

Of 26, 829 children presenting with possible EV71 disease, 2.9% (767) were admitted, more from less developed areas than from Shanghai proper. Of these, 29.2% (224) had severe enough EV71 for study enrolment, 4 excluded for underlying disease. Of 220 enrolled, 40.5% (89) had neurological involvement, 10.5% (23) needed pediatric intensive care unit care and 3% (7) died. Factors associated with severe disease were young age, male gender, high white count, prolonged high fever, high glucose, high C-reactive protein and neurological findings. The majority with neurological involvement and all who died were from the countryside. Early intravenous gamma globulin intervention had better survival. No survivor had persistent sequelae 2 months after discharge.

CONCLUSIONS

This study confirms the morbidity for EV71 disease in China, especially for patients from the countryside versus Shanghai proper. The potential impact of public education, an EV71 vaccine, and the potential benefits versus harms of IVIG treatment are discussed.

Coxsackievirus B1 reveals strain specific differences in plasmacytoid dendritic cell mediated immunogenicity

Enterovirus infections are usually mild but can also cause severe illnesses and play a role in chronic diseases, such as cardiomyopathies and type 1 diabetes. Host response to the invading virus can markedly modulate the course of the infection, and this response varies between individuals due to the polymorphism of immune response genes. However, it is currently not known if virus strains also differ in their ability to stimulate the host immune system. Coxsackievirus B1 (CBV1) causes severe epidemics in young infants and it has recently been connected with type 1 diabetes in seroepidemiological studies. This study evaluated the ability of different field isolates of CBV1 to induce innate immune responses in PBMCs. CBV1 strains differed markedly in their capacity to induce innate immune responses. Out of the 18 tested CBV1 strains two induced exceptionally strong alpha interferon (IFN-α) response in PBMC cultures. The responding cell type was found to be the plasmacytoid dendritic cell. Such a strong innate immune response was accompanied by an up-regulation of several other immune response genes and secretion of cytokines, which modulate inflammation, and adaptive immune responses. These results suggest that enterovirus-induced immune activation depends on the virus strain. It is possible that the immunotype of the virus modulates the course of the infection and plays a role in the pathogenesis of chronic immune-mediated enterovirus diseases.

Prevalence of enteroviruses in children with and without hand, foot, and mouth disease in China

Background

To determine the prevalence of human enteroviruses (HEVs) among healthy children, their parents, and children with hand, foot, and mouth disease (HFMD).

Methods

We conducted a case–control study that included throat samples from 579 children with HFMD and from 254 healthy controls. Throat samples from 49 households (98 parents and 53 healthy children) were also analyzed. Phylogenetic analysis was carried out to study genetic relationships of EV71 strains.

Results

The HEV positive rate in HFMD patients was significantly higher than that in healthy controls (76.0% vs. 23.2%, P < 0.001). The EV71 (43.7% vs. 15.0%, P < 0.001), CVA16 (18.0% vs. 2.8%, P < 0.001), and CVA10 (5.7% vs. 0.8%, P = 0.001) serotypes were significantly overrepresented in HFMD patients in comparison to healthy children. Other HEV serotypes were detected with comparable frequency in cases and controls. The HEV positive rate in severe HFMD patients was significantly higher than that in mild group (82.1% vs. 73.8%, P = 0.04). The EV71 (55.0% vs. 39.7%, P = 0.001) and CVA16 (11. 9% vs. 20.0%, P = 0.024) positive rate differed significantly between severe and mild HFMD patients. Other HEV serotypes were detected with comparable frequency between severe and mild HFMD patients. Among 49 households, 22 households (44.9%) had at least 1 family member positive for HEV. Children had significantly higher HEV positive rate than adult (28.3% vs. 14.3%, P = 0.037). The HEV positive rate was similar between mothers and fathers (12.24% vs. 16.32%, P = 0.56). The VP1 sequences of EV71 from HFMD patients and healthy children were nearly identical and all were clustered in the same clade, C4a.

Conclusions

Our study demonstrated the co-circulation of multiple HEV serotypes in children with and without HFMD during epidemic. Our study deserves the attention on HFMD control.

Human enterovirus 71 epidemics: what's next?

Human enterovirus 71 (EV71) epidemics have affected various countries in the past 40 years. EV71 commonly causes hand, foot and mouth disease (HFMD) in children, but can result in neurological and cardiorespiratory complications in severe cases. Genotypic changes of EV71 have been observed in different places over time, with the emergence of novel genotypes or subgenotypes giving rise to serious outbreaks. Since the late 1990s, intra- and inter-typic recombination events in EV71 have been increasingly reported in the Asia-Pacific region. In particular, 'double-recombinant' EV71 strains belonging to a novel genotype D have been predominant in mainland China and Hong Kong over the last decade, though co-circulating with a minority of other EV71 subgenotypes and coxsackie A viruses. Continuous surveillance and genome studies are important to detect potential novel mutants or recombinants in the near future. Rapid and sensitive molecular detection of EV71 is of paramount importance in anticipating and combating EV71 outbreaks.