Epidemiological, molecular, and clinical features of enterovirus respiratory infections in French children between 1999 and 2005

Global landscape of coxsackieviruses in human health

Coxsackieviruses-induced infections, particularly in infants and young children, are one of the most important public health issues in low- and middle-income countries, where the surveillance system varies substantially, and these manifestations have been disregarded. They are widespread throughout the world and are responsible for a broad spectrum of human diseases, from mildly symptomatic conditions to severe acute and chronic disorders. Coxsackieviruses (CV) have been found to have 27 identified genotypes, with overlaps in clinical phenotypes between genotypes. In this review, we present a concise overview of the most recent studies and findings of coxsackieviruses-associated disorders, along with epidemiological data that provides comprehensive details on the distribution, variability, and clinical manifestations of different CV types. We also highlight the significant roles that CV infections play in the emergence of neurodegenerative illnesses and their effects on neurocognition. The current role of CVs in oncolytic virotherapy is also mentioned. This review provides readers with a better understanding of coxsackieviruses-associated disorders and pointing the impact that CV infections can have on different organs with variable pathogenicity. A deeper knowledge of these infections could have implications in designing current surveillance and prevention strategies related to severe CVs-caused infections, as well as encourage studies to identify the emergence of more pathogenic types and the etiology of the most common and most severe disorders associated with coxsackievirus infection.

Molecular Amplification and Cell Culturing Efficiency for Enteroviruses' Detection in Cerebrospinal Fluids of Algerian Patients Suffering from Meningitis

Enteroviruses (EVs) represent a major cause of viral meningitis, being responsible for nearly 1 billion infections each year worldwide. Several techniques were developed to obtain better diagnostic results of EV infections. Herein, we evaluated the efficiency of EV detection through isolation on both Rhabdomyosarcoma (RD) and Vero cell line cultures, conventional reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR. Thus, 50 cerebrospinal fluid (CSF) samples belonging to patients suspected to have viral meningitis in northern Algeria were collected, anonymously numbered from 1 to 50 and subjected to the above-mentioned techniques for EV detection. Using real-time RT-PCR, 34 CSF samples were revealed to be positive for viral origin of meningitis (68%). Thirteen of them were positive when the conventional RT-PCR was used (26%), and only three samples gave positive results when the cell culture technique was used (6%). Surprisingly, two cell culture-positive CSF samples, namely, 31 and 39, were negative using RT-PCR directly on the original samples. However, they turned to be positive when amplification was carried out on their corresponding cell culture supernatant. The cell-cultured viral isolates were then identified by sequencing their viral genome's VP1 regions. All of them were revealed to belong to the echovirus 27 strain. This investigation demonstrates that RT-PCR techniques are often more sensitive, accurate and much faster, providing reliable results within a clinically acceptable timeframe. However, viral isolation on cell cultures remains crucial to obtain enough viral load for serological tests or even to avoid the rare, but existing, false negative PCR.

Non-polio enterovirus aseptic meningitis in infants up to three months of age, the bacterial mask of viral disease: A retrospective cohort study

BACKGROUND

Non-polio enterovirus aseptic meningitis (NPE-AM) is a self-limiting illness that can mimic serious bacterial infection (SBI) in infants during their first months of life.

OBJECTIVES

To compare the clinical features of febrile infants diagnosed with NPE-AM with those of infants who had SBI or non-bacterial infection (NBI).

STUDY DESIGN

A systematic series of febrile infants < 3-months-old hospitalized between 2010 and 2019 with febrile illness in a tertiary hospital. Clinical and laboratory data were compared between the three groups.

RESULTS

Overall 1278 infants were included; 207 (16.2%) had NPE-AM, 210 (16.4%) SBI and 861 (67.4%) NBI. The median age was 34 (IQR: 21.5-51.7) days. NPE-AM was documented in 25% of infants < 29 days and 9.9% of infants aged 29-90 days. Infants with NPE-AM or SBI had fever >39°C more frequently, 24.2% and 17.1% compared with 10% in infants with NBI (p < 0.001). Fever duration ≥ 2 days was reported in 3.4% of infants with NPE-AM vs 18.6% in SBI and 26.3% in NBI (p < 0001); rash occurred in 37.7% in NPE-AM compared to 4.6% in NBI and 5.7% in SBI (p < 0.001). The mean white blood count, C-reactive protein and absolute neutrophil count were significantly lower in infants with NPE-AM compared to infants with the SBI (p < 0.001) and similar to the means in infants with NBI (p = 0.848, 0.098 and 0.764 respectively). A high proportion of bloody tap 346/784 (53.1%) was detected. Infants with NPE-AM were more likely to be treated with antibiotics than infants with NBIs (88.9% vs 50.7%, p < 0.001), similarly to infants with SBIs (p = 0.571).

CONCLUSIONS

The clinical presentation of infants with NPE-AM that could mimic bacterial infection and the high rate of bloody taps may lead to more hospital admissions and antibiotic prescriptions. Rapid molecular testing for detection of NPE may be of additional value in the evaluation of febrile infants.

Cytolytic Properties and Genome Analysis of Rigvir® Oncolytic Virotherapy Virus and Other Echovirus 7 Isolates

Rigvir® is a cell-adapted, oncolytic virotherapy enterovirus, which derives from an echovirus 7 (E7) isolate. While it is claimed that Rigvir® causes cytolytic infection in several cancer cell lines, there is little molecular evidence for its oncolytic and oncotropic potential. Previously, we genome-sequenced Rigvir® and five echovirus 7 isolates, and those sequences are further analyzed in this paper. A phylogenetic analysis of the full-length data suggested that Rigvir® was most distant from the other E7 isolates used in this study, placing Rigvir® in its own clade at the root of the phylogeny. Rigvir® contained nine unique mutations in the viral capsid proteins VP1-VP4 across the whole data set, with a structural analysis showing six of the mutations concerning residues with surface exposure on the cytoplasmic side of the viral capsid. One of these mutations, E/Q/N162G, was located in the region that forms the contact interface between decay-accelerating factor (DAF) and E7. Rigvir® and five other isolates were also subjected to cell infectivity assays performed on eight different cell lines. The used cell lines contained both cancer and non-cancer cell lines for observing Rigvir®'s claimed properties of being both oncolytic and oncotropic. Infectivity assays showed that Rigvir® had no discernable difference in the viruses' oncolytic effect when compared to the Wallace prototype or the four other E7 isolates. Rigvir® was also seen infecting non-cancer cell lines, bringing its claimed effect of being oncotropic into question. Thus, we conclude that Rigvir®'s claim of being an effective treatment against multiple different cancers is not warranted under the evidence presented here. Bioinformatic analyses do not reveal a clear mechanism that could elucidate Rigvir®'s function at a molecular level, and cell infectivity tests do not show a discernable difference in either the oncolytic or oncotropic effect between Rigvir® and other clinical E7 isolates used in the study.

Life-Threatening Enterovirus 71 Encephalitis in Unrelated Children with Autosomal Dominant TLR3 Deficiency

PURPOSE

Enterovirus A71 (EV71) causes a broad spectrum of childhood diseases, ranging from asymptomatic infection or self-limited hand-foot-and-mouth disease (HFMD) to life-threatening encephalitis. The molecular mechanisms underlying these different clinical presentations remain unknown. We hypothesized that EV71 encephalitis in children might reflect an intrinsic host single-gene defect of antiviral immunity. We searched for mutations in the toll-like receptor 3 (TLR3) gene. Such mutations have already been identified in children with herpes simplex virus encephalitis (HSE).

METHODS

We sequenced TLR3 and assessed the impact of the mutations identified. We tested dermal fibroblasts from a patient with EV71 encephalitis and a TLR3 mutation and other patients with known genetic defects of TLR3 or related genes, assessing the response of these cells to TLR3 agonist poly(I:C) stimulation and EV71 infection.

RESULTS

Three children with EV71 encephalitis were heterozygous for rare mutations-TLR3 W769X, E211K, and R867Q-all of which were shown to affect TLR3 function. Furthermore, fibroblasts from the patient heterozygous for the W769X mutation displayed an impaired, but not abolished, response to poly(I:C). We found that TLR3-deficient and TLR3-heterozygous W769X fibroblasts were highly susceptible to EV71 infection.

CONCLUSIONS

Autosomal dominant TLR3 deficiency may underlie severe EV71 infection with encephalitis. Human TLR3 immunity is essential to protect the central nervous system against HSV-1 and EV71. Children with severe EV71 infections, such as encephalitis in particular, should be tested for inborn errors of TLR3 immunity.

Prevalence and Bayesian Phylogenetics of Enteroviruses Derived From Environmental Surveillance Around Polio Vaccine Switch Period in Shandong Province, China

We present the results of environmental surveillance for poliovirus (PV) and non-poliovirus (NPEV) around the switch from trivalent to bivalent oral polio-vaccine (OPV) which occurred in China in May 2016. Sewage samples were collected in Jinan and Linyi city from 2015 to 2017. Enterovirus (EV) isolation, VP1 amplification, Sanger sequencing, and phylogenetic analyses were performed. Among105 sewage samples (36 in Jinan and 69 in Linyi), 101 were positive for EV, with 74.3% (78/105) PV-positive samples and 90.5% (95/105) NPEV-positive samples. A total of 893 EV isolates were obtained, including 326 (36.5%) PVs and 567 (63.5%) NPEVs. Echovirus (E) -11 was the most common serotype out of 18 detected NPEV types (120/567), followed by E-3 (75/567) and E-6 (74/567). PV2 vanished and PV3 came to be the ascendant PV type in sewage after May 2016. Eight PV isolates were judged as pre-vaccine-derived poliovirus (pre-VDPV) and no VDPV or wild PV isolates were monitored. Bayesian phylogenetics demonstrated global E-11 originated in 1876 and evolved with the estimated rate of 4.63 × 10^-3 nucleotide substitutions per site per year (s/s/y). Multiple circulating clusters that originated at different times were coexisting in Shandong province. The most recently common ancestor of global coxsackievirus B5 could date back to 1867, at the evolutionary rate of 3.95 × 10^-3 s/s/y. In conclusion, our study described the changes of PVs and NPEVs around the polio vaccine switch period and provided meaningful global molecular epidemiological data for further studies of EV-related diseases among the population.

Epidemiologic and Molecular Study of EVs in Hospitalized Children With Severe Acute Respiratory Infection

BACKGROUND

To evaluate the enterovirus (EV)-positivity rate in respiratory samples collected from children ≤15 years hospitalized with severe acute respiratory infections (SARIs) and to describe the epidemiologic and molecular characteristics of EVs.

METHODS

Respiratory samples were collected from 2468 children hospitalized with SARI at a university and research hospital in Milan (September 1, 2014 to August 31, 2017). EV and EV-D68 RNA were detected using a commercial multiplex and a specific real-time RT-PCR assay, respectively. The EV-D68-negative samples were then characterized by partial sequencing of the VP1 gene.

RESULTS

EV-RNA was detected in 9% (222/2468) of SARI cases, 77% were children ≤3 years, almost 13% of whom required intensive care. EVs circulated all-year-round in 2 distinct epidemic waves (May-August and November-December). An EV-D68 outbreak, responsible for 14.8% of EV-positive-SARIs, occurred in 2016 and 5 newly emerging EV types were identified. Twenty-two EV types were detected and remarkable heterogeneity was observed in species distribution and between different pediatric age groups.

CONCLUSIONS

This study showed that EV-positivity rate for our SARI series was 9%. The molecular detection and characterization of EVs allowed for the rapid detection of an EV-D68 outbreak and revealed the presence of emerging EV types that may pose a public health threat. The lack of routine screening and EV characterization in respiratory tract infections hampers the assessment of their epidemiologic and molecular features.

Recombination in Enteroviruses, a Multi-Step Modular Evolutionary Process

RNA recombination is a major driving force in the evolution and genetic architecture shaping of enteroviruses. In particular, intertypic recombination is implicated in the emergence of most pathogenic circulating vaccine-derived polioviruses, which have caused numerous outbreaks of paralytic poliomyelitis worldwide. Recent experimental studies that relied on recombination cellular systems mimicking natural genetic exchanges between enteroviruses provided new insights into the molecular mechanisms of enterovirus recombination and enabled to define a new model of genetic plasticity for enteroviruses. Homologous intertypic recombinant enteroviruses that were observed in nature would be the final products of a multi-step process, during which precursor nonhomologous recombinant genomes are generated through an initial inter-genomic RNA recombination event and can then evolve into a diversity of fitter homologous recombinant genomes over subsequent intra-genomic rearrangements. Moreover, these experimental studies demonstrated that the enterovirus genome could be defined as a combination of genomic modules that can be preferentially exchanged through recombination, and enabled defining the boundaries of these recombination modules. These results provided the first experimental evidence supporting the theoretical model of enterovirus modular evolution previously elaborated from phylogenetic studies of circulating enterovirus strains. This review summarizes our current knowledge regarding the mechanisms of recombination in enteroviruses and presents a new evolutionary process that may apply to other RNA viruses.

Prematurity, a significant predictor for worse outcome in viral bronchiolitis: a comparative study in infancy

Background

The rate of admissions to hospital with bronchiolitis has increased over the past years. The reasons for this are likely to be multifactorial including improved survival of preterm infants.

Aim

To assess the severity of viral bronchiolitis in preterm compared to term infants admitted at a tertiary hospital in Cairo, Egypt, based on the outcome.

Patients and methods

This prospective study was conducted throughout a 3-year period from September 2011 to October 2014. It included 153 infants, 74 healthy preterm, and 79 healthy term infants admitted with clinical diagnosis of bronchiolitis at a tertiary hospital in Cairo, Egypt. Bronchiolitis severity score (BSS) was recorded, and nasopharyngeal swabs were obtained from each patient at the time of presentation. Viruses were identified using reverse transcription polymerase chain reaction (RT-PCR). The clinical course and patient’s outcome were recorded.

Results

This study recorded a significantly more severe BSS for preterm compared to term infants. The preterm group had an increased mean length of hospital stay and oxygen therapy and was more likely to need intensive care unit admission and mechanical ventilation (MV) compared to the term group. The mean (± SD) BSS for infections with h-MPV, RSV, and para-influenza 3 was more significantly severe in preterm compared to term infants. Bacterial co-infection was significantly correlated with severity scoring in both groups.

Conclusion

Prematurity significantly affects the severity of bronchiolitis, and this underscores the importance of early categorization as a high-risk group on their first visit. The physician should be aware that their illness runs a more severe course, even if they have no underlying disorders.

Characterization of respiratory infection viruses in hospitalized children from Naples province in Southern Italy

Most acute respiratory infections (ARIs) in children are due to viral etiology, and represent an important cause of mortality and morbidity in children <5 years old in developing countries. The pathogens that cause ARIs vary geographically and by season, and viruses serve a major role. In the present study, the distribution of the seven respiratory viruses that are more prevalent in Southern European countries were retrospectively analyzed in a Southern Italy Hospital, that centralizes pediatric diseases from the Naples province. Viruses were categorized by a FilmArray Respiratory Panel, and demonstrated no substantial differences in sex, age and seasonal viruses distribution. However, all the investigated viruses had a higher detection rate in the surrounding municipalities than in the metropolitan area of Naples. In recent years, the association between air pollution and respiratory infections has become an increasing public health concern. The data in this study support this association in the surrounding areas of Naples extensively contaminated by environmental toxic agents. In these areas, characterization of the epidemiology of ARIs is required to implement a prevention and control program.

Pre-Clinical and Clinical Efficiency of Complexes of Oligoribonucleotides with D-Mannitol against Respiratory Viruses

Oligoribonucleotides-D-mannitol (ORNs-D-M) complexes possess antiviral, anti-inflammatory, and immunomodulatory actions. The aim of the present study was to evaluated an antiviral effect of ORNs-D-M against parainfluenza virus type 3 (PIV3); influenza CA709, PR834; avian influenza virus H5N2 (AIV) in vitro by a TCID₅₀; hemadsorption and neuraminidase activity assays; and clinical efficiency of ORNs-D-M in patients with acute respiratory infections (ARIs) of various etiologies by PCR assay and AmpliSens test systems. It was observed that ORNs-D-M have an antiviral activity against the influenza CA709, PR834, PIV3, and AIV in vitro. The injectable dosage form of ORNs-D-M was shown to have a stronger antiviral effect compared to capsule form. It was also detected that the injectable form of ORNs-D-M significantly reduced the neuraminidase activity of influenza PR834. A complex treatment of patients with ORNs-D-M had a positive effect on the course of the disease, it accelerated patients’ recovery. Treatment with ORNs-D-M caused eradication of adeno- and influenza viruses in patients with ARI. This drug contributed to significant decrease in duration of febrile period and cough. Comprehensive treatment with ORNs-D-M improved the disease clinical findings significantly. Collectively, these results suggested that ORNs-D-M may be used at co-infection with influenza and other respiratory viruses as a medical antiviral drug.

Genome Sequences of RIGVIR Oncolytic Virotherapy Virus and Five Other Echovirus 7 Isolates

We report here the nearly complete Illumina-sequenced consensus genome sequences of six isolates of echovirus 7 (E7), including oncolytic virotherapy virus RIGVIR and the Wallace prototype. Amino acid identities within the coding region were highly conserved across all isolates, ranging from 95.31% to 99.73%.

Epidemiology and clinical profile of pathogens responsible for the hospitalization of children in Sousse area, Tunisia

This study aimed to identify a broad spectrum of respiratory pathogens from hospitalized and not-preselected children with acute respiratory tract infections in the Farhat Hached University-hospital of Sousse, Tunisia. Between September 2013 and December 2014, samples from 372 children aged between 1 month and 5 years were collected, and tested using multiplex real-time RT-PCR by a commercial assay for 21 respiratory pathogens. In addition, samples were screened for the presence of Streptococcus pneumoniae 16S rDNA using real-time PCR. The viral distribution and its association with clinical symptoms were statistically analyzed. Viral pathogens were detected in 342 (91.93%) of the samples of which 28.76% were single positive and 63.17% had multiple infections. The most frequent detected viruses were rhinovirus (55.64%), respiratory syncytial virus A/B (33.06%), adenovirus (25.00%), coronavirus NL63, HKU1, OC43, and 229E (21.50%), and metapneumovirus A/B (16.12%). Children in the youngest age group (1–3 months) exhibited the highest frequencies of infection. Related to their frequency of detection, RSV A/B was the most associated pathogen with patient’s demographic situation and clinical manifestations (p<0.05). Parainfluenza virus 1–4 and parechovirus were found to increase the risk of death (p<0.05). Adenovirus was statistically associated to the manifestation of gastroenteritis (p = 0.004). Rhinovirus infection increases the duration of oxygen support (p = 0.042). Coronavirus group was statistically associated with the manifestation of bronchiolitis (p = 0.009) and laryngitis (p = 0.017). Streptococcus pneumoniae DNA was detected in 143 (38.44%) of tested samples. However, only 53 samples had a concentration of C-reactive protein from equal to higher than 20 milligrams per liter, and 6 of them were single positive for Streptocuccus pneumoniae. This study confirms the high incidence of respiratory viruses in children hospitalized for acute respiratory tract infections in the Sousse area, Tunisia.

African Non-Human Primates Host Diverse Enteroviruses

Enteroviruses (EVs) belong to the family Picornaviridae and are responsible for mild to severe diseases in mammals including humans and non-human primates (NHP). Simian EVs were first discovered in the 1950s in the Old World Monkeys and recently in wild chimpanzee, gorilla and mandrill in Cameroon. In the present study, we screened by PCR EVs in 600 fecal samples of wild apes and monkeys that were collected at four sites in Gabon. A total of 32 samples were positive for EVs (25 from mandrills, 7 from chimpanzees, none from gorillas). The phylogenetic analysis of VP1 and VP2 genes showed that EVs identified in chimpanzees were members of two human EV species, EV-A and EV-B, and those identified in mandrills were members of the human species EV-B and the simian species EV-J. The identification of two novel enterovirus types, EV-B112 in a chimpanzee and EV-B113 in a mandrill, suggests these NHPs could be potential sources of new EV types. The identification of EV-B107 and EV90 that were previously found in humans indicates cross-species transfers. Also the identification of chimpanzee-derived EV110 in a mandrill demonstrated a wide host range of this EV. Further research of EVs in NHPs would help understanding emergence of new types or variants, and evaluating the real risk of cross-species transmission for humans as well for NHPs populations.

Epidemiological and etiological characteristics of herpangina and hand foot mouth diseases in Jiangsu, China, 2013-2014

Herpangina (HA) and hand, foot, and mouth disease (HFMD) are common infectious diseases caused by human enteroviruses and frequently occurr in young children. Previous published studies have mainly focused on HFMD, while the HA epidemiological and etiological characteristics in mainland China have not been described. From June, 2013 to March, 2014, HA and HFMD patients were monitored in participants from clinical trial of EV-A71 vaccine conducted during 2012-2013. A total of 95 HA patients and 161 HFMD patients were defined. Enteroviruses of HA samples were differentiated into 17 serotypes (EV-A71, CV-A16, CV-A24, E6, CV-B5, CV-A22, CV-A6, CV-A10, CV-B3, E9, CV-A9, CV-B4, CV-B2, E1, E7, E21 and CV-A20), the most common serotypes were EV-A71(10/95,10.5%), CV-A16(4/95,4.2%) and CV-A24(4/95,4.2%); while enteroviruses detected from HFMD samples were classfied into 21 serotypes ( EV-A71, CV-A16, CV-A10, CV-A6, E6, CV-B3, CV-B5, CV-A9, E9, CV-B2, CV-B4, E3, E11, E15, E16, CV-A1, EV-A69, E5, CA22, CA24 and EV99), the most common serotypes were EV-A71(28/161,17.4%), CV-A16(7/161,4.4%) and CV-A10(5/161,3.1%). The first HA epidemic peak occurred in summer and a second smaller peak occurred in January. In HA patients, the body temperature (P < 0.0001) and the incidence of fever (P < 0.05) were significant higher than those in HFMD patients. Between HA and HFMD patients infected with EV-A71, no significant differences were found in age, sex, circulating season, and the viral genome diversity. In summary, we firstly reported the epidemiological and etiological characteristics of HA in mainland China. Developing a multivalent vaccine will be helpful for the control of the HA/HFMD epidemic.

Risk of Nephrotic Syndrome following Enteroviral Infection in Children: A Nationwide Retrospective Cohort Study

PURPOSE

Nephrotic syndrome is a common chronic illness encountered during childhood. Infections have been identified as a cause of nephrotic syndrome. The aim of this study was to evaluate the association between enteroviral infection and nephrotic syndrome.

METHODS

A nationwide retrospective cohort study was conducted by analyzing data from the National Health Insurance Research Database in Taiwan. Children aged <18 years with enteroviral infection were enrolled. Non-enterovirus-infected children were randomly selected as the comparison cohort. The primary endpoint was the occurrence of nephrotic syndrome.

METHODS

This study included 280,087 enterovirus-infected children and 280,085 non-enterovirus-infected children. The mean age of the enterovirus-infected children was 2.38 years, and 53.7% of these children were boys. The overall incidence densities of nephrotic syndrome for enterovirus- and non-enterovirus-infected children were 2.65 and 2.21 per 10,000 person-years, respectively. The enterovirus-infected cohort had a higher cumulative incidence of nephrotic syndrome than did the non-enterovirus-infected cohort (log-rank test, p = 0.01). Multivariable analyses revealed that children with enteroviral infection were significantly associated with an increased risk of nephrotic syndrome compared with those without enteroviral infection (adjusted hazard ratio, 1.20; 95% confidence interval, 1.04-1.39; p = 0.01), particularly in children infected with coxsackievirus. Subgroup analyses revealed that enterovirus-infected girls, children of blue-collar workers, and children without allergies had a higher risk of nephrotic syndrome than did children in the non-enterovirus-infected cohort.

CONCLUSION

This study revealed a significant association between enteroviral infection and nephrotic syndrome. Additional studies elucidating the role and pathogenesis of enterovirus in nephrotic syndrome are warranted.

Update on Human Rhinovirus and Coronavirus Infections

Human rhinovirus (HRV) and coronavirus (HCoV) infections are associated with both upper respiratory tract illness (“the common cold”) and lower respiratory tract illness (pneumonia). New species of HRVs and HCoVs have been diagnosed in the past decade. More sensitive diagnostic tests such as reverse transcription-polymerase chain reaction have expanded our understanding of the role these viruses play in both immunocompetent and immunosuppressed hosts. Recent identification of severe acute respiratory syndrome and Middle East respiratory syndrome viruses causing serious respiratory illnesses has led to renewed efforts for vaccine development. The role these viruses play in patients with chronic lung disease such as asthma makes the search for antiviral agents of increased importance.

Lower anti-echovirus antibody responses in children presenting to hospital with asthma exacerbations

BACKGROUND

Rhinoviruses from the Enterovirus genus cause frequent infections and induce remarkably high titres of anticapsid antigen antibodies in asthmatics, while the prevalence of neutralising antibodies to the gut-trophic echoviruses from the same genus is diminished.

OBJECTIVE

To assess the absolute and specific antibody titres to VP1 antigens of the gut-trophic enteroviruses, echovirus 30 and Sabin 1 poliovirus, in asthmatic and non-asthmatic children.

METHODS

Recombinant polypeptides representing the VP1 capsid antigens of echovirus 30 and Sabin poliovirus 1 were produced. Their ability to bind IgG1 antibodies from the plasma of asthmatic (n = 45) and non-asthmatic (n = 29) children were quantitated by immunoassays that incorporated immunoabsorptions to remove cross-reactivity.

RESULTS

The IgG1 antibody titres and prevalence of antibody binding to echovirus 30 were significantly lower for asthmatic children compared to controls (P < 0.05) and inversely correlated with total IgE levels for the whole study population (r = -0.262; P < 0.05). There was no difference in the prevalence and titre between groups to the VP1 antigen of Sabin poliovirus. Anti-tetanus toxoid titres measured for comparison did not correlate with anti-echovirus or poliovirus, but correlated with anti-rhinovirus titres in controls but not asthmatics, where the titres were higher for the asthmatic group.

CONCLUSIONS AND CLINICAL RELEVANCE

The associations of lower antibody titres of asthmatic children to echovirus reported here and those of our previous findings of a heightened response to rhinovirus suggest a dichotomy where respiratory enterovirus infection/immunity increases the probability of developing asthma and enteric infections lower the risk. This provides further support for the concept of intestinal infection playing a key role in the development of allergic respiratory disease.

Genotyping of enteroviruses isolated in Kenya from pediatric patients using partial VP1 region

Enteroviruses (EV) are responsible for a wide range of clinical diseases in humans. Though studied broadly in several regions of the world, the genetic diversity of human enteroviruses (HEV) circulating in the sub-Saharan Africa remains under-documented. In the current study, we molecularly typed 61 HEV strains isolated in Kenya between 2008 and 2011 targeting the 3′-end of the VP1 gene. Viral RNA was extracted from the archived isolates and part of the VP1 gene amplified by RT-PCR, followed by sequence analysis. Twenty-two different EV types were detected. Majority (72.0 %) of these belonged to Enterovirus B species followed by Enterovirus D (21.3 %) and Enterovirus A (6.5 %). The most frequently detected types were Enterovirus-D68 (EV-D68), followed by Coxsackievirus B2 (CV-B2), CV-B1, CV-B4 and CV-B3. Phylogenetic analyses of these viruses revealed that Kenyan CV-B1 isolates were segregated among sequences of global CV-B1 strains. Conversely, the Kenyan CV-B2, CV-B3, CV-B4 and EV-D68 strains generally grouped together with those detected from other countries. Notably, the Kenyan EV-D68 strains largely clustered with sequences of global strains obtained between 2008 and 2010 than those circulating in recent years. Overall, our results indicate that HEV strains belonging to Enterovirus D and Enterovirus B species pre-dominantly circulated and played a significant role in pediatric respiratory infection in Kenya, during the study period. The Kenyan CV-B1 strains were genetically divergent from those circulating in other countries. Phylogenetic clustering of Kenyan EV-D68 strains with sequences of global strains circulating between 2008 and 2010 than those obtained in recent years suggests a high genomic variability associated with the surface protein encoding VP1 gene in these enteroviruses.

Evolution and phylogeographic dissemination of endemic porcine picornaviruses in Vietnam

Members of the Picornaviridae are important and often zoonotic viruses responsible for a variety of human and animal diseases. However, the evolution and spatial dissemination of different picornaviruses circulating in domestic animals are not well studied. We examined the rate of evolution and time of origin of porcine enterovirus G (EV-G) and porcine kobuvirus species C lineages (PKV-C) circulating in pig farms in Vietnam and from other countries. We further explored the spatiotemporal spread of EV-G and PKV-C in Southwest Vietnam using phylogeographic models. Multiple types of EV-G are co-circulating in Vietnam. The two dominant EV-G types among isolates from Vietnam (G1 and G6) showed strong phylogenetic clustering. Three clades of PKV-C (PKV-C1-3) represent more recent introductions into Vietnam; PKV-C2 is closely related to PKV-C from Southwest China, indicating possible cross-border dissemination. In addition, high virus lineage migration rates were estimated within four districts in Dong Thap province in Vietnam for both EV-G types (G1, G6) and all PKV-C (C1-3) clades. We found that Chau Thanh district is a primary source of both EV-G and PKV-C clades, consistent with extensive pig trading in and out of the district. Understanding the evolution and spatial dissemination of endemic picornaviruses in pigs may inform future strategies for the surveillance and control of picornaviruses.

Molecular Epidemiology of Human Rhinoviruses and Enteroviruses Highlights Their Diversity in Sub-Saharan Africa

Human rhinoviruses (HRVs) and enteroviruses (HEVs) belong to the Enterovirus genus and are the most frequent cause of infection worldwide, but data on their molecular epidemiology in Africa are scarce. To understand HRV and HEV molecular epidemiology in this setting, we enrolled febrile pediatric patients participating in a large prospective cohort assessing the causes of fever in Tanzanian children. Naso/oropharyngeal swabs were systematically collected and tested by real-time RT-PCR for HRV and HEV. Viruses from positive samples were sequenced and phylogenetic analyses were then applied to highlight the HRV and HEV types as well as recombinant or divergent strains. Thirty-eight percent (378/1005) of the enrolled children harboured an HRV or HEV infection. Although some types were predominant, many distinct types were co-circulating, including a vaccinal poliovirus, HEV-A71 and HEV-D68. Three HRV-A recombinants were identified: HRV-A36/HRV-A67, HRV-A12/HRV-A67 and HRV-A96/HRV-A61. Four divergent HRV strains were also identified: one HRV-B strain and three HRV-C strains. This is the first prospective study focused on HRV and HEV molecular epidemiology in sub-Saharan Africa. This systematic and thorough large screening with careful clinical data management confirms the wide genomic diversity of these viruses, brings new insights about their evolution and provides data about associated symptoms.

Non-rhinovirus enteroviruses associated with respiratory infections in Peru (2005-2010)

Background

Enteroviruses (EVs) are a common cause of respiratory tract infections and are classified into seven species (EVA-D and rhinoviruses [RHVs] A-C) with more than 200 different serotypes. Little is known about the role of non-RHV EVs in respiratory infections in South America. The aim of this study was to describe the epidemiology of non-RHV EVs detected in patients with influenza-like illness enrolled in a passive surveillance network in Peru.

Methods

Throat swabs and epidemiological data were collected from participants after obtaining verbal consent. Viral isolation was performed in cell culture and identified by immunofluorescence assay. Serotype identification of EV isolates was performed using commercial monoclonal antibodies. Identification of non-serotypeable isolations was carried out by reverse transcriptase-PCR, followed by sequencing.

Results

Between 2005 and 2010, 24,239 samples were analyzed, and 9,973 (41.1%) possessed at least one respiratory virus. EVs were found in 175 samples (0.7%). Our results revealed a clear predominance of EVB species, 90.9% (159/175). No EVDs were isolated. The mean and median ages of EV-positive subjects were 9.1 and 4.0 years, respectively, much younger than the population sampled, 17.6 and 12.0 years. Sixteen serotypes were identified, four EVA, 11 EVB, and one EVC species. The most common serotypes were coxsackievirus B1, coxsackievirus B2, coxsackievirus B5, and coxsackievirus B3.

Conclusion

This study provides data about the serotypes of EVs circulating in Peru and sets the need for further studies.

Viral etiology and seasonality of influenza-like illness in Gabon, March 2010 to June 2011

Background

Surveillance of influenza-like illness (ILI) in Central Africa began only recently, and few data are therefore available on the circulation of influenza virus and other respiratory viruses. In Gabon, a Central African country, we established a surveillance network in four major towns in order to analyze cases of ILI among patients who visited health centers between March 2010 and June 2011, and to determine the viral etiology.

Methods

Nasal swabs were sent for analysis to the Centre International de Recherches Médicales de Franceville, where they were screened for 17 respiratory viruses in a multiplex real-time reverse transcription polymerase chain reaction for all pathogens according the following pairs: adenovirus/parainfluenza virus 4, respiratory syncytial virus/human metapneumovirus, parainfluenza virus 1/parainfluenza virus 2, pandemic influenza virus A/seasonal influenza virus A (H1N1, H3N2)/seasonal influenza virus B, human coronaviruses 229E/OC43, human coronaviruses NL63/HKU1, rhinovirus/human parechovirus, and enterovirus/parainfluenza virus 3.

Results

We analyzed a total of 1041 specimens, of which 639 (61%) were positive for at least one virus. Three-quarters of the patients were children under five years old. We therefore focused on this age group, in which 68.1% of patients were positive for at least one virus. The most common viruses were adenoviruses (17.5%), followed by parainfluenza viruses (PIVs) 1–4 (16.8%), enteroviruses (EV) (14.7%), respiratory syncytial virus (RSV) (13.5%), and influenza virus (11.9%). The prevalence of some viruses was subject to geographic and seasonal variations. One-third of positive samples contained more than one virus.

Conclusions

Like most studies in the world, the virus PIVs, EV, RSV, Influenza virus, HRV were predominant among children under five years old in Gabon. An exception is made for adenoviruses which have a high prevalence in our study. However adenoviruses can be detected in asymptomatic persons. These finding gave a better knowledge of the circulation and the seasonality of the viruses involved in ILI in Gabon.

Clinical features of coxsackievirus A4, B3 and B4 infections in children

Background

Clinical features of coxsackievirus A4 (CA4), B3 (CB3) and B4 (CB4) infections in children have not been comprehensively described.

Methods/Principal Findings

From January 2004 to June 2012, a total of 386 children with culture-proven CA4, CB3 and CB4 infections treated at Chang Gung Memorial Hospital, including 296 inpatients (CA4, 103; CB3, 131; CB4, 62) and 90 outpatients (CA4, 55; CB3, 14; CB4, 21), were included. From outpatients, only demographics were extracted and from inpatients, detailed clinical and laboratory data were collected retrospectively. The mean age was 32.1±30.2 months; male to female ratio was 1.3∶1. Children with CB3 infection were youngest (76.6% <3 years of age), and had a highest hospitalization rate (90.3%) and a longest duration of hospitalization (mean ± SD, 7.5±6.2 days). Herpangina (74.8%) was the most common presentation for children with CA4 infection, aseptic meningitis (26.7%) and young infant with fever (23.7%) for those with CB3 infection, and herpangina (32.3%) and tonsillitis/pharyngitis (27.4%) for children with CB4 infection. Almost all the inpatients had fever (97.6%). Twelve out of thirteen (92.3%) children with complications and ten of 11 children with long-term sequelae had CB3 infections. Two fatal cases were noted, one due to myocarditis with CA4 infection and CB3 were detected from the other case which had hepatic necrosis with coagulopathy. The remaining 285 children (96.3%) recovered uneventfully.

Conclusion

CA4, CB3 and CB4 infections in children had different clinical disease spectrums and involved different age groups. Though rare, severe diseases may occur, particularly caused by CB3.

Prevalence of nonpolio enteroviruses in the sewage of Guangzhou city, China, from 2009 to 2012

The human-pathogenic viruses in urban sewage have been extensively monitored to obtain information on circulating viruses in human communities. Enteroviruses (EVs) excreted by patients who present with diverse clinical syndromes can remain infectious in the environment for several weeks, and limited data on circulating environmental EVs are available. A 4-year (2009 to 2012) surveillance study was conducted to detect nonpolio enteroviruses (NPEVs) in the urban sewage of Guangzhou city, China. After the viruses in the sewage samples were concentrated and isolated, molecular identification was used to detect and type the NPEVs. During the 4-year study, 17 different NPEV serotypes were identified in the sewage of Guangzhou city. The most common serotypes were echovirus 11 (ECHO11), ECHO6, ECHO7, and ECHO12 and coxsackie group B viruses 5 (CVB5) and CVB3. The predominant serotypes were influenced by spatial and temporal factors and differed each year. CVB5 was commonly detected in 2009 and 2010 but was rarely isolated in 2011 and 2012. In contrast, CVB3 was not observed in 2009 and 2010 but was increasingly detected in 2011 and 2012. Our study provides an overview of the serotype distribution and circulation patterns of NPEVs in the sewage of Guangzhou, China. In the absence of a systematic EV disease surveillance system, the detection and characterization of sewage-borne NPEVs will help us better understand the changes in EV disease trends and the epidemic background of circulating EVs, which could help interpret the EV trends and warn of future outbreaks in this area.

Human astrocytic cells support persistent coxsackievirus B3 infection

Enteroviruses can frequently target the human central nervous system to induce a variety of neurological diseases. Although enteroviruses are highly cytolytic, emerging evidence has shown that these viruses can establish persistent infections both in vivo and in vitro. Here, we investigated the susceptibility of three human brain cell lines, CCF-STTG1, T98G, and SK-N-SH, to infection with three enterovirus serotypes: coxsackievirus B3 (CVB3), enterovirus 71, and coxsackievirus A9. Persistent infection was observed in CVB3-infected CCF-STTG1 cells, as evidenced by prolonged detection of infectious virions, viral RNA, and viral antigens. Of note, infected CCF-STTG1 cells expressed the nonfunctional canonical viral receptors coxsackievirus-adenovirus receptor and decay-accelerating factor, while removal of cell surface chondroitin sulfate from CCF-STTG1 cells inhibited the replication of CVB3, suggesting that receptor usage was one of the major limiting factors in CVB3 persistence. In addition, CVB3 curtailed the induction of beta interferon in infected CCF-STTG1 cells, which likely contributed to the initiation of persistence. Furthermore, proinflammatory chemokines and cytokines, such as vascular cell adhesion molecule 1, interleukin-8 (IL-8), and IL-6, were upregulated in CVB3-infected CCF-STTG1 cells and human progenitor-derived astrocytes. Our data together demonstrate the potential of CCF-STTG1 cells to be a novel cell model for studying CVB3-central nervous system interactions, providing the basis toward a better understanding of CVB3-induced chronic neuropathogenesis.

Enteroviruses as major cause of microbiologically unexplained acute respiratory tract infections in hospitalized pediatric patients

OBJECTIVE

To assess the etiological role and the clinical characteristics of HRV and HEV infections in pediatric patients hospitalized for acute respiratory tract infections (ARTIs).

METHODS

RT-qPCR assays and molecular sequencing methods were used to identify HRV and HEV strains in nasopharyngeal aspirates of 309 hospitalized pediatric patients with microbiologically unexplained ARTIs and in 210 hospitalized pediatric patients without respiratory symptoms from September 2009 to June 2010 in France.

RESULTS

Among the 309 ARTI cases, 15 HEV and 172 HRV strains were identified whereas only 1 HEV and 37 HRV strains were observed in control patients (187 vs. 38: P < 10(-3)). HRV strains were identified in 150 of the 164 lower ARTIs whereas HEV strains were identified in only 14 of these cases. Among bronchiolitis and asthma exacerbation cases (n = 133), HEV infected cases were older (Median age (months) 36 vs. 11, P = 0.003) and were more frequently associated with a respiratory distress (P = 0.01) and a need for oxygen supply at the time of admission (P = 0.01) than cases infected by HRV strains.

CONCLUSION

HRV and HEV strains were identified as potential etiological causes of 60.5% of microbiologically unexplained ARTIs diagnosed in hospitalized pediatric cases. A higher clinical severity was observed in HEV infected bronchiolitis or asthma exacerbation cases in comparison to HRV infected cases.

Coxsackievirus A21, enterovirus 68, and acute respiratory tract infection, China

During August 2006-April 2010, in Beijing, China, 2 rare human enterovirus serotypes, coxsackievirus A21 and enterovirus 68, were detected most frequently in human enterovirus-positive adults with acute respiratory tract infections. Thus, during some years, these 2 viruses cause a substantial proportion of enterovirus-associated adult acute respiratory tract infections.

Picornavirus and enterovirus diversity with associated human diseases

Members of the Picornaviridae family are non-enveloped, positive-stranded RNA viruses with a 30nm icosahedral capsid. This virus family exhibits a considerable amount of genetic variability driven both by mutation and recombination. Recently, three previously unknown human picornaviruses, namely the human Saffold cardiovirus, cosavirus and salivirus, have been identified in stools or respiratory samples from subjects presenting symptoms ranging from gastroenteritis to acute flaccid paralysis. However, these viruses were also frequently detected in asymptomatic subjects and their clinical relevance remains to be elucidated. The Enterovirus genus is a prototype example of the Picornaviridae heterogeneity at both genetic and phenotypic levels. This genus is divided into 10 species, seven of which contain human viruses, including three Rhinovirus species. Both human rhino- and enteroviruses are also characterized by high levels of genetic variability, as exemplified by the existence of over 250 different serotypes and the recent discovery of new enterovirus genotypes and the Rhinovirus C species. Despite their common genomic features, rhinoviruses are restricted to the respiratory tract, whereas the vast majority of enteroviruses infect the gastrointestinal tract and can spread to other organs, such as the heart or the central nervous system. Understanding the genetic determinants of such phenotypic diversity is an important challenge and a field for future investigation. Better characterization of these ubiquitous human pathogens may help to develop vaccines or antiviral treatments and to monitor the emergence of new strains.

Enterovirus infection in Korean children and anti-enteroviral potential candidate agents

Although most enterovirus infections are not serious enough to be life threatening, several enteroviruses such as enterovirus 71 are responsible for severe, potentially life-threatening disease. The epidemic patterns of enteroviruses occur regularly during the year, but they may change due to environmental shifts induced by climate change due to global warming. Therefore, enterovirus epidemiological studies should be performed continuously as a basis for anti-viral studies. A great number of synthesized antiviral compounds that work against enteroviruses have been developed but only a few have demonstrated effectiveness in vivo. No proven effective antiviral agents are available for enterovirus disease therapy. The development of a new antiviral drug is a difficult task due to poor selective toxicity and cost. To overcome these limitations, one approach is to accelerate the availability of other existing antiviral drugs approved for antiviral effect against enteroviruses, and the other way is to screen traditional medicinal plants.

Risks associated with the use of live-attenuated vaccine poliovirus strains and the strategies for control and eradication of paralytic poliomyelitis

The Global Polio Eradication Initiative was launched in 1988 with the aim to eliminate paralytic poliomyelitis. Two effective vaccines are available: inactivated polio vaccine (IPV) and oral polio vaccine (OPV). Since 1964, OPV has been used instead of IPV in most countries due to several economic and biological advantages. However, in rare cases, the live-attenuated Sabin strains of OPV revert to neurovirulence and cause vaccine-associated paralytic poliomyelitis in vaccinees or lead to emergence of vaccine-derived poliovirus strains. Attenuating mutations and recombination events have been associated with the reversion of vaccine strains to neurovirulence. The substitution of OPV with an improved new-generation IPV and the availability of new specific drugs against polioviruses are considered as future strategies for outbreak control and the eradication of paralytic poliomyelitis worldwide.

Enteroviruses isolated from herpangina and hand-foot-and-mouth disease in Korean children

Hand-foot-and-mouth disease (HFMD) and herpangina are commonly prevalent illness in young children. They are similarly characterized by lesions on the skin and oral mucosa. Both diseases are associated with various enterovirus serotypes. In this study, enteroviruses from patients with these diseases in Korea in 2009 were isolated and analyzed. Demographic data for patients with HFMD and herpangina were compared and all enterovirus isolates were amplified in the VP1 region by reverse transcription-polymerase chain reaction and sequenced. Among the enterovirus isolates, prevalent agents were coxsackievirus A16 in HFMD and coxsackievirus A5 in herpangina. More prevalent months for HFMD were June (69.2%) and May (11.5%), and June (40.0%) and July (24.0%) for herpangina. Age prevalence of HFMD patients with enterovirus infection was 1 year (23.1%), 4 years (19.2%), and over 5 years (19.2%). However, the dominant age group of herpangina patients with enterovirus infection was 1 year (48.0%) followed by 2 years (28.0%). Comparison of pairwise VP1 nucleotide sequence alignment of all isolates within the same serotypes revealed high intra-type variation of CVA2 isolates (84.6–99.3% nucleotide identity). HFMD and herpangina showed differences in demographic data and serotypes of isolated enteroviruses, but there was no notable difference in amino acid sequences by clinical syndromes in multiple comparison of the partial VP1 gene sequence.

Broad respiratory virus detection in infants hospitalized for bronchiolitis by use of a multiplex RT-PCR DNA microarray system

Newly available molecular tools allow a sensitive detection of a broad panel of viruses in respiratory tract specimens. In the present study, the application of a multiplex RT‐PCR DNA microarray in diagnosis and epidemiological survey of viral infections in infants hospitalized for bronchiolitis was assessed. One hundred and thirty‐eight nasopharyngeal aspirates collected from October 2007 to September 2008 were tested by direct immunofluorescence and viral culture, a combination of referenced RT‐PCRs and the DNA microarray. One or more viruses were detected in 96, 126 and 126 of the specimens by direct immunofluorescence and viral culture, RT‐PCRs and DNA microarray, respectively (70 vs. 91 vs. 91%, P < 10⁻³). The RT‐PCRs and the DNA microarray yielded concordant results for 99% of specimens and identified mixed viral infections in 85 (62%). The most common associations were: human bocavirus and respiratory syncytial virus (32%), adenovirus and respiratory syncytial virus (30%), and parainfluenza virus type 3 and respiratory syncytial virus (23%). None of the bronchiolitis severity parameters including intensive care unit admission, O₂ supply, O₂ saturation percentage, O₂ length and length of stay at the hospital appeared to be significantly increased in multiple viral infections compared to single viral infections (P > 0.1). In conclusion, the use of this DNA microarray in clinical virology practice allows rapid and accurate identification of common and uncommon viral respiratory pathogens in infants hospitalized for bronchiolitis. It should improve the clinical management, the epidemiological survey, and the prevention of the nosocomial transmission of respiratory viruses in pediatric wards. J. Med. Virol. 84:979–985, 2012. © 2012 Wiley Periodicals, Inc.

Human enterovirus 109 (EV109) in acute paediatric respiratory disease in Hungary

Human enterovirus 109 (EV109) is a recently identified recombinant enterovirus in family Picornaviridae from acute paediatric respiratory illness in Nicaragua. EV109 have not been reported elsewhere. Our aims were the molecular detection and genetic analysis of EV109 from acute childhood respiratory infections in Hungary. Nasopharyngeal aspirates were collected from children under age of 10 years with acute respiratory infections treated in Department of Pulmonology, Kaposi Mór Teaching Hospital, Mosdós, Hungary. Samples were taken from 15 October to 15 May in two respiratory seasons 2005/2006 and 2006/2007. Samples were tested using EV109 specific VP1 primers by RT-PCR method. One (1.1%) of the 92 nasopharyngeal aspirates was positive for EV109 collected from a 2.5-year-old child in January, 2007. The main symptoms were dropping nose, fever (38.1°C), hard cough and wheezing associated with bronchitis and pneumonia. Based upon the VP1 gene region EV109 (L87/HUN/2007, JN900470) has 93% nucleotide identity and identical recombinant pattern to the prototype EV109. This is the first detection of the novel recombinant enterovirus, EV109, in Hungary (in Europe). This study supports the possibility that EV109 is able to cause acute respiratory infections, in addition, it might be plays a part in lower respiratory disease with hospitalization in children.

Human rhinovirus and human respiratory enterovirus (EV68 and EV104) infections in hospitalized patients in Italy, 2008-2009

The epidemiology of picornavirus infections along with associated risk factors for lower respiratory tract infections (LRTI) and duration of virus shedding were investigated in 985 hospitalized patients in the period October 2008-September 2009. One-third of patients were human rhinovirus (HRV)-positive. Of 336 HRV-associated episodes, 153 (45.5%) were sustained by HRV-A, 31 (9.2%) by HRV-B, and 93 (27.7%) by HRV-C, while 7 episodes showed multiple HRV types and 52 were sustained by undefined HRV species. Independent risk factors for LRTI included high viral load and age less than 5 years. Twenty (2.1%) patients were enterovirus (EV)-positive (12 had EV-68, 7 EV-104, and 1 E-13 infection). Half of the EV-positive patients had a LRTI and were younger with respect to patients with upper RTI (median 18 months versus 37 years; P < 0.001). HRVs are often the cause of LRTI in children less than 5 years, frequently in association with a high viral load.

Epidemics of enterovirus infection in Chungnam Korea, 2008 and 2009

Previously, we explored the epidemic pattern and molecular characterization of enteroviruses isolated in Chungnam, Korea from 2005 to 2006. The present study extended these observations to 2008 and 2009. In this study, enteroviruses showed similar seasonal prevalent pattern from summer to fall and age distribution to previous investigation. The most prevalent month was July: 42.9% in 2008 and 31.9% in 2009. The highest rate of enterovirus-positive samples occurred in children < 1-year-old-age. Enterovirus-positive samples were subjected to sequence determination of the VP1 region, which resolved the isolated enteroviruses into 10 types in 2008 (coxsackievirus A4, A16, B1, B3, echovirus 6, 7, 9, 11, 16, and 30) and 8 types in 2009 (coxsackievirus A2, A4, A5, A16, B1, B5, echovirus 11, and enterovirus 71). The most prevalent enterovirus serotype in 2008 and 2009 was echovirus 30 and coxsackievirus B1, respectively, whereas echovirus 18 and echovirus 5 were the most prevalent types in 2005 and 2006, respectively. Comparison of coxsackievirus B1 and B5 of prevalent enterovirus type in Korea in 2009 with reference strains of each same serotype were conducted to genetic analysis by a phylogenetic tree. The sequences of coxsackievirus B1 strains segregated into four distinct clusters (A, B, C, and D) with some temporal and regional sub-clustering. Most of Korean coxsackievirus B1 strains in 2008 and 2009 were in cluster D, while only "Kor08-CVB1-001CN" was cluster C. The coxsackievirus B5 strains segregated in five distinct genetic groups (clusters A-E) were supported by high bootstrap values. The Korean strains isolated in 2001 belonged to cluster D, whereas Korean strains isolated in 2005 and 2009 belonged to cluster E. Comparison of the VP1 amino acid sequences of the Korean coxsackievirus B5 isolates with reference strains revealed amino acid sequence substitutions at nine amino acid sequences (532, 562, 570, 571, 576-578, 582, 583, and 585).

Genus-specific substitution rate variability among picornaviruses

Picornaviruses have some of the highest nucleotide substitution rates among viruses, but there have been no comparisons of evolutionary rates within this broad family. We combined our own Bayesian coalescent analyses of VP1 regions from four picornaviruses with 22 published VP1 rates to produce the first within-family meta-analysis of viral evolutionary rates. Similarly, we compared our rate estimates for the RNA polymerase 3D(pol) gene from five viruses to four published 3D(pol) rates. Both a structural and a nonstructural gene show that enteroviruses are evolving, on average, a half order of magnitude faster than members of other genera within the Picornaviridae family.

The airway epithelium: soldier in the fight against respiratory viruses

The airway epithelium acts as a frontline defense against respiratory viruses, not only as a physical barrier and through the mucociliary apparatus but also through its immunological functions. It initiates multiple innate and adaptive immune mechanisms which are crucial for efficient antiviral responses. The interaction between respiratory viruses and airway epithelial cells results in production of antiviral substances, including type I and III interferons, lactoferrin, β-defensins, and nitric oxide, and also in production of cytokines and chemokines, which recruit inflammatory cells and influence adaptive immunity. These defense mechanisms usually result in rapid virus clearance. However, respiratory viruses elaborate strategies to evade antiviral mechanisms and immune responses. They may disrupt epithelial integrity through cytotoxic effects, increasing paracellular permeability and damaging epithelial repair mechanisms. In addition, they can interfere with immune responses by blocking interferon pathways and by subverting protective inflammatory responses toward detrimental ones. Finally, by inducing overt mucus secretion and mucostasis and by paving the way for bacterial infections, they favor lung damage and further impair host antiviral mechanisms.

Viral etiologies of acute respiratory infections among hospitalized Vietnamese children in Ho Chi Minh City, 2004-2008

BACKGROUND

The dominant viral etiologies responsible for acute respiratory infections (ARIs) are poorly understood, particularly among hospitalized children in resource-limited tropical countries where morbidity and mortality caused by ARIs are highest. Improved etiological insight is needed to improve clinical management and prevention.

OBJECTIVES

We conducted a three-year prospective descriptive study of severe respiratory illness among children from 2 months to 13 years of age within the largest referral hospital for infectious diseases in southern Vietnam.

METHODS

Molecular detection for 15 viral species and subtypes was performed on three types of respiratory specimens (nose, throat swabs and nasopharyngeal aspirates) using a multiplex RT-PCR kit (Seeplex™ RV detection, Seegene) and additional monoplex real-time RT-PCRs.

RESULTS

A total of 309 children were enrolled from November 2004 to January 2008. Viruses were identified in 72% (222/309) of cases, including respiratory syncytial virus (24%), influenza virus A and B (17%), human bocavirus (16%), enterovirus (9%), human coronavirus (8%), human metapneumovirus (7%), parainfluenza virus 1-3 (6%), adenovirus (5%), and human rhinovirus A (4%). Co-infections with multiple viruses were detected in 20% (62/309) of patients. When combined, diagnostic yields in nose and throat swabs were similar to nasopharyngeal aspirates.

CONCLUSION

Similar to other parts in the world, RSV and influenza were the predominant viral pathogens detected in Vietnamese hospitalized children. Combined nasal and throat swabs are the specimens of choice for sensitive molecular detection of a broad panel of viral agents. Further research is required to better understand the clinical significance of single versus multiple viral coinfections and to address the role of bacterial (co-)infections involved in severe respiratory illness.

Enterovirus infection and type 1 diabetes mellitus: systematic review and meta-analysis of observational molecular studies

OBJECTIVE

To review the association between current enterovirus infection diagnosed with molecular testing and development of autoimmunity or type 1 diabetes.

DESIGN

Systematic review and meta-analysis of observational studies, analysed with random effects models.

DATA SOURCES

PubMed (until May 2010) and Embase (until May 2010), no language restrictions, studies in humans only; reference lists of identified articles; and contact with authors. Study eligibility criteria Cohort or case-control studies measuring enterovirus RNA or viral protein in blood, stool, or tissue of patients with pre-diabetes and diabetes, with adequate data to calculate an odds ratio and 95% confidence intervals.

RESULTS

The 24 papers and two abstracts (all case-control studies) that met the eligibility criteria included 4448 participants. Study design varied greatly, with a high level of statistical heterogeneity. The two separate outcomes were diabetes related autoimmunity or type 1 diabetes. Meta-analysis showed a significant association between enterovirus infection and type 1 diabetes related autoimmunity (odds ratio 3.7, 95% confidence interval 2.1 to 6.8; heterogeneity χ(2)/df = 1.3) and clinical type 1 diabetes (9.8, 5.5 to 17.4; χ(2)/df = 3.2).

CONCLUSIONS

There is a clinically significant association between enterovirus infection, detected with molecular methods, and autoimmunity/type 1 diabetes. Larger prospective studies would be needed to establish a clear temporal relation between enterovirus infection and the development of autoimmunity and type 1 diabetes.

Epidemiologic and clinical features of non-polio enteroviral infections in northern Taiwan in 2008

BACKGROUND

Non-polio enteroviruses may cause different diseases, including herpangina, hand-foot-mouth disease (HFMD), meningitis, and nonspecific febrile illness; and cause epidemic outbreak annually. This study delineates the diversity of clinical presentations based on different serotypes and different groups [human enterovirus (HEV)-A and HEV-B] of enteroviruses (EVs) during the 2008 epidemic in National Taiwan University Hospital (NTUH).

METHODS

We retrospectively identified patients younger than 18 years who had positive isolates of non-polio EV in throat swabs, rectal swabs, or cerebrospinal fluid, in NTUH from January 1 to December 31, 2008. For serotyping, immunofluorescence assay and polymerase chain reaction followed by viral structure protein-1 sequencing were applied. We analyzed and compared their clinical features among different serotypes and different groups of EVs.

RESULTS

Among 172 patients who were enrolled, 16 serotypes were identified. The major serotype in NTUH was EV71 (25.6%) followed by coxsackievirus A (CA)16 and coxsackievirus B (CB)4. EV71 manifested mostly as HFMD (89%) and was complicated with encephalomyelitis in three patients. Serotypes of HFMD included EV71 (70%), CA16 (27%), CA4, and CA6. Serotypes of herpangina were heterogeneous, and the major serotype was CA2 (35.7%) followed by CB4 (23.8%). Aseptic meningitis was entirely caused by HEV-B and mostly infected by echovirus 30 (50%). Among children with EV-related respiratory tract infection, CB4 (32%) was dominant in upper respiratory tract infection, whereas echovirus 4 (71%) was the major cause of lower respiratory tract infection. Cases of HEV-A were significantly younger than the cases of HEV-B (p = 0.04). Multivariate analysis revealed that the most significant factor associated with hospitalization is HEV-B (odds ratio, 2.2; 95% confidence interval, 1.1-4.2; p = 0.02).

CONCLUSIONS

At least 16 serotypes circulated in northern Taiwan in 2008. EV71 is the predominant strain in this outbreak. All patients with HFMD were infected by HEV-A, but HEV-B was associated with a higher rate of hospitalization and aseptic meningitis, which should be a cause of alert regarding public health.

Enterovirus genotype EV-104 in humans, Italy, 2008-2009

In an epidemiologic investigation of respiratory infections in Italy, October 2008–September 2009, we tested samples from patients for respiratory viruses. Human enterovirus genotype EV-104 (identified in Switzerland) was found in 3 immunocompromised and 2 immunocompetent patients. EV-104 is closely related to human rhinoviruses; thus, both types of viruses should be sought in respiratory syndromes.

Human enterovirus 109: a novel interspecies recombinant enterovirus isolated from a case of acute pediatric respiratory illness in Nicaragua

Enteroviruses (Picornaviridae family) are a common cause of human illness worldwide and are associated with diverse clinical syndromes, including asymptomatic infection, respiratory illness, gastroenteritis, and meningitis. In this study, we report the identification and complete genome sequence of a novel enterovirus isolated from a case of acute respiratory illness in a Nicaraguan child. Unbiased deep sequencing of nucleic acids from a nose and throat swab sample enabled rapid recovery of the full-genome sequence. Phylogenetic analysis revealed that human enterovirus 109 (EV109) is most closely related to serotypes of human enterovirus species C (HEV-C) in all genomic regions except the 5' untranslated region (5' UTR). Bootstrap analysis indicates that the 5' UTR of EV109 is likely the product of an interspecies recombination event between ancestral members of the HEV-A and HEV-C groups. Overall, the EV109 coding region shares 67 to 72% nucleotide sequence identity with its nearest relatives. EV109 isolates were detected in 5/310 (1.6%) of nose and throat swab samples collected from children in a pediatric cohort study of influenza-like illness in Managua, Nicaragua, between June 2007 and June 2008. Further experimentation is required to more fully characterize the pathogenic role, disease associations, and global distribution of EV109.

Respiratory echovirus 30 and coxsackievirus B5 can induce production of RANTES, MCP-1 and IL-8 by human bronchial epithelial cells

Human Enteroviruses (HEV) (picornaviridae) are considered as one the major viral causes of childhood acute respiratory wheezing illnesses including bronchiolitis and asthma exacerbation. To identify the mechanisms that can regulate the development of airway mucosa inflammation during HEV respiratory lower tract infection, we investigated the profile and the levels of mRNA and protein secretion for CC and CXC human chemokines by HEV-infected primary human bronchial epithelial cells (SAE cells) using RT-PCR array and Bio-Plex assay. Cultures of SAE cells were infected by reference and wild-type HEV respiratory strains, demonstrating a replicative and productive viral infection. We observed that the replicative infection of the SAE cells by reference and wild-type HEV strains induced specific dose and time-dependent increases in mRNA and protein secretion only for RANTES, MCP-1 and IL-8 and not for all other CC and CXC human chemokines tested. The protein secretion of these chemokines appeared to be significantly increased at 48 or 72h post-infection in cultures treated by low-doses of IFN-gamma comparatively to mock-infected cells (P<0.001), and was correlated to the viral replication activity. In conclusion, our findings demonstrated a selective production of RANTES, IL-8 and MCP-1 released by HEV-infected epithelial cells of the small bronchioles along with mechanisms of amplification mediated by IFN-gamma.

Immunofluorescence versus xTAG multiplex PCR for the detection of respiratory picornavirus infections in children

Background

Polymerase chain reaction (PCR) is a sensitive tool for detection of respiratory picornaviruses. However, the clinical relevance of picornavirus detection by PCR is unclear. Immunofluorescence (IF), widely used to detect other respiratory viruses, has recently been introduced as a promising detection method for respiratory picornaviruses.

Objectives

To compare the clinical manifestations of respiratory picornavirus infections detected by IF with those of respiratory picornavirus infections detected by xTAG multiplex PCR in hospitalized children.

Study design

During a 1-year period, nasopharyngeal aspirates (NPA) from all children hospitalized due to an acute respiratory infection were prospectively analyzed by IF. All respiratory picornavirus positive IF samples and 100 IF negative samples were further tested with xTAG multiplex PCR. After exclusion of children with co-morbidities and viral co-infections, monoinfections with respiratory picornaviruses were detected in 108 NPA of 108 otherwise healthy children by IF and/or PCR. We compared group 1 children (IF and PCR positive, n = 84) with group 2 children (IF negative and PCR positive, n = 24) with regard to clinical manifestations of the infection.

Results

Wheezy bronchitis was diagnosed more often in group 1 than in group 2 (71% vs. 46%, p = 0.028). In contrast, group 2 patients were diagnosed more frequently with pneumonia (17% vs. 6%, p = 0.014) accompanied by higher levels of C-reactive protein (46 mg/l vs. 11 mg/l, p = 0.009).

Conclusions

Picornavirus detection by IF in children with acute respiratory infection is associated with the clinical presentation of wheezy bronchitis. The finding of a more frequent diagnosis of pneumonia in picornavirus PCR positive but IF negative children warrants further investigation.

High rate of viral identification and coinfections in infants with acute bronchiolitis

OBJECTIVES

To determine the viruses and risk factors associated with hospital and intensive care unit (ICU) admissions in infants with acute bronchiolitis.

INTRODUCTION

Bronchiolitis is a major cause of morbidity in infants. Widespread use of molecular-based methods has yielded new insights about its etiology, but the impact of viral etiologies on early outcomes is still unclear.

METHODS

Seventy-seven infants with bronchiolitis who were under two years of age and visited an emergency unit were included. Using molecular-based methods, samples were tested for 12 different respiratory viruses. Logistic regression models were used to identify clinical and virological variables associated with the main endpoints: hospital admission and ICU admission.

RESULTS

We identified at least one virus in 93.5% of patients, and coinfections were found in nearly 40% of patients. RSV was the most common pathogen (63.6%), followed by rhinovirus (39%). Identification of RSV was only associated with an increased risk of hospital admission in the univariate model. Younger age and enterovirus infection were associated with an increased risk of hospital admission, while atopy of a first-degree relative showed a protective effect. Prematurity was associated with an increased risk of admission to the ICU. Coinfections were not associated with worse outcomes.

CONCLUSIONS

Molecular-based methods resulted in high rates of viral identification but did not change the significant role of RSV in acute bronchiolitis. Younger age and enterovirus infection were risk factors for hospital admission, while prematurity appeared to be a significant risk factor for admission to the ICU in acute viral bronchiolitis.

Enteroviruses in Spain over the decade 1998-2007: virological and epidemiological studies

BACKGROUND

Human enteroviruses (HEV) are the commonest cause of viral meningitis as well as other pathologies, therefore HEV characterization is important both in patient management and epidemiological investigation.

OBJECTIVES

A 10-year study of patients with enteroviral infection was carried out in Spain to determine the underlying etiology.

STUDY DESIGN

HEV were fully typed by microneutralisation tests and/or molecular methods.

RESULTS

A collection of 86404 clinical samples were studied in several Spanish laboratories. These were collected from patients with different syndromes, mainly aseptic meningitis (AM), fever, respiratory diseases and acute flaccid paralysis. Of these, 6867 HEV were obtained. At the National Poliovirus Laboratory 2814 were serotypically characterised. Among non-polio enteroviruses, the eight main serotypes were Echovirus 30 (25%), Echovirus 6 (12.4%), Echovirus 13 (8.3%), Echovirus 11 (7.4%) and Echovirus 9 (4.7%), followed by Coxsackievirus B5 (4.2%) and Echovirus 7 and Coxsackievirus A9 (3.7%) each. In AM cases, Echovirus 30 was identified in 39% of them, followed by Echovirus 6 (14%). However, Echovirus 6 was mainly associated with respiratory disease (17%), followed by Echovirus 11 (10%). On the other hand, Echovirus 30, Echovirus 11 and Echovirus 6 contributed equally with 12% of each serotype in the cases of fever.

CONCLUSIONS

The present report complements previous data (Trallero et al.(13)), with the results of HEV incidence in Spain from 1998 to 2007. The surveillance described in this study provided valuable information as to which serotypes are in circulation, the emergence of new HEV and association with clinical manifestations.