Non-polio enteroviruses and their association with acute diarrhea in children in India

Epidemiology of Enterovirus Genotypes in Association with Human Diseases

Enteroviruses (EVs) are well-known causes of a wide range of infectious diseases in infants and young children, ranging from mild illnesses to severe conditions, depending on the virus genotypes and the host's immunity. Recent advances in molecular surveillance and genotyping tools have identified over 116 different human EV genotypes from various types of clinical samples. However, the current knowledge about most of these genotypes, except for those of well-known genotypes like EV-A71 and EV-D68, is still limited due to a lack of comprehensive EV surveillance systems. This limited information makes it difficult to understand the true burden of EV-related diseases globally. Furthermore, the specific EV genotype associated with diseases varies according to country, population group, and study period. The same genotype can exhibit different epidemiological features in different areas. By integrating the data from established EV surveillance systems in the USA, Europe, Japan, and China, in combination with other EV infection studies, we can elaborate a better understanding of the distribution of prevalent EV genotypes and the diseases associated with EV. This review analyzed the data from various EV surveillance databases and explored the EV seroprevalence and the association of specific EV genotypes with human diseases.

Enterovirus genotype diversity with emergence of coxsackievirus A2 circulating in pediatric patients with acute gastroenteritis in Thailand, 2019-2022

Introduction

Enteroviruses (EVs) are recognized as potential causative agents of acute gastroenteritis (AGE) in children worldwide. This study aimed to investigate the epidemiology and molecular characteristics of EV infection in children admitted to hospitals with AGE in Chiang Mai, Thailand from 2019 to 2022.

Methods

A total of 1,148 fecal samples collected from patients with AGE were screened for the presence of EV using RT-PCR. The prevalence, co-infection with common diarrheal viruses, and seasonal pattern of EV were examined. The genotypes of EV were identified based on the VP1 sequence and phylogenetic analysis.

Results

The overall prevalence of EV in AGE patients was 8.8% (101/1,148). After the COVID-19 outbreak in 2019, a significant decrease in the EV infection rate and genotype diversity was observed (p < 0.05). EV infection alone was observed in 68.3% (69/101) of cases while co-infection with other enteric viruses was 31.7% (32/101). The seasonal pattern of EV infection showed a peak prevalence during the rainy season. EV species A was the most prevalent (37.5%), followed by species B (32.3%), species C (29.2%), and species D (1.0%). Twenty-five genotypes of EV were identified with the most predominant of the coxsackievirus A2 (CV-A2) (13.5%), CV-B2 (7.3%) and CV-A24 (5.2%).

Conclusion

Our data demonstrate a significant decrease in the prevalence and diversity of EV circulating in AGE patients during the COVID-19 pandemic and highlight the emergence of CV-A2 during this study period. These findings contribute to a better understanding of the molecular epidemiology and diversity of EV in patients with AGE and provide useful information for further investigation into the potential association between specific EV genotypes and AGE in future studies.

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.

Phylogenetic characteristics and recombination analysis of echovirus 5 associated with severe acute respiratory infection in China

IMPORTANCE

This study is the first report of echovirus 5 (E5) associated with severe acute respiratory infection and obtained the first E5 whole-genome sequence in China. Combined with the sequences available in the GenBank database, the first genotyping, phylogenetic characteristics, recombination, and genetic evolutionary analysis of E5 was performed in this study. Our findings providing valuable information on global E5 molecular epidemiology.

Molecular Characteristics of Enterovirus B83 Strain Isolated from a Patient with Acute Viral Myocarditis and Global Transmission Dynamics

This study determined the global genetic diversity and transmission dynamics of enterovirus B83 (EV-B83) and proposed future disease surveillance directions. Blood samples were collected from a patient with viral myocarditis, and viral isolation was performed. The complete genome sequence of the viral isolate was obtained using Sanger sequencing. A dataset of 15 sequences (from three continents) that had sufficient time signals for Bayesian phylogenetic analysis was set up, and the genetic diversity and transmission dynamics of global EV-B83 were analyzed using bioinformatics methods, including evolutionary dynamics, recombination event analysis, and phylogeographic analysis. Here, we report the complete genome sequence of an EV-B83 strain (S17/YN/CHN/2004) isolated from a patient with acute viral myocarditis in Yunnan Province, China. All 15 EV-B83 strains clustered together in a phylogenetic tree, confirming the classification of these isolates as a single EV type, and the predicted time for the most recent common ancestor appeared in 1998. Recombinant signals were detected in the 5'-untranslated region and 2A-3D coding regions of the S17 genome. The phylogeographic analysis revealed multiple intercontinental transmission routes of EV-B83. This study indicates that EV-B83 is globally distributed. Our findings add to the publicly available EV-B83 genomic sequence data and deepen our understanding of EV-B83 epidemiology.

Genomic Epidemiology and Transmission Dynamics of Global Coxsackievirus B4

The aim of this study was to determine the global genetic diversity and transmission dynamics of coxsackievirus B4 (CVB4) and to propose future directions for disease surveillance. Next-generation sequencing was performed to obtain the complete genome sequence of CVB4, and the genetic diversity and transmission dynamics of CVB4 worldwide were analyzed using bioinformatics methods such as phylogenetic analysis, evolutionary dynamics, and phylogeographic analysis. Forty complete genomes of CVB4 were identified from asymptomatic infected individuals and hand, foot, and mouth disease (HFMD) patients. Frequent recombination between CVB4 and EV-B multiple serotypes in the 3D^pol region was found and formed 12 recombinant patterns (A-L). Among these, the CVB4 isolated from asymptomatic infected persons and HFMD patients belonged to lineages H and I, respectively. Transmission dynamics analysis based on the VP1 region revealed that CVB4 epidemics in countries outside China were dominated by the D genotype, whereas the E genotype was dominant in China, and both genotypes evolved at a rate of > 6.50 × 10^-3 substitutions/site/year. CVB4 spreads through the population unseen, with the risk of disease outbreaks persisting as susceptible individuals accumulate. Our findings add to publicly available CVB4 genomic sequence data and deepen our understanding of CVB4 molecular epidemiology.

Enterovirus detection in stool samples from Mozambican children with acute gastroenteritis

Enteroviruses (EV) are predominantly enteric viruses, present in all parts of the world causing disease in humans with a broad spectrum of clinical presentations. The purpose of this study was to identify non-polio enteroviruses (NPEV) in stool samples collected from children with acute gastroenteritis (AGE) symptoms of unknown etiology in four provinces (Maputo, Nampula, Sofala and Zambézia) of Mozambique. From June 2014 to March 2018, 327 stool samples were collected from children hospitalized with AGE in health care units. NPEVs were detected in 52 samples (52/327; 15.9%) and were more frequent in children under 5 years of age. The age group from 12 to 23 months was the most affected and showed more severity of disease. We also identified 26 different EV-types with the following detection pattern EV-B>EV-C>EV-A. The major EV-types were EV-A119 (9/52; 17.3%) and EV-C99 (8/52; 15.4%), accounting for 32.7% of the total. In addition to EV-A119, other uncommon EV-types were also identified, such as EV-B75, EV-B97 and EV-C113. The current study shows a high heterogeneity of EV types circulating in children with AGE in Mozambique as well as the identification of rarely described enteroviruses.

Molecular Characteristics and Genetic Evolution of Echovirus 33 in Mainland of China

Echovirus, a member of the Enterovirus B (EV-B) family, has led to numerous outbreaks and pandemics, causing a broad spectrum of diseases. Based on the national hand, foot, and mouth disease (HFMD) surveillance system, seven strains of echovirus 33 (E33) were isolated from Mainland of China between 2010 and 2018. The whole genomes of these strains were isolated and sequenced, and phylogenetic trees were constructed based on the gene sequences in different regions of the EV-B prototype strains. It was found that E33 may be recombined in the P2 and P3 regions. Five genotypes (A–E) were defined based on the entire VP1 region of E33, of which the C gene subtype was the dominant gene subtype at present. Recombinant analysis showed that genotype C strains likely recombined with EV-B80, EV-B85, E13, and CVA9 in the P2 and P3 regions, while genotype E had the possibility of recombination with CVB3, E3, E6, and E4. Results of Bayesian analysis indicated that E33 may have appeared around 1955 (95% confidence interval: 1945–1959), with a high evolutionary rate of 1.11 × 10⁻² substitution/site/year (95% highest posterior density (HPD): 8.17 × 10⁻³ to 1.4 × 10⁻² substitution/site/year). According to spatial transmission route analysis, two significant transmission routes were identified: from Australia to India and from Oman to Thailand, which the E33 strain in Mainland of China likely introduced from Mexico and India. In conclusion, our study fills the gaps in the evolutionary analysis of E33 and can provide important data for enterovirus surveillance.

Enterovirus detection in different regions of Madagascar reveals a higher abundance of enteroviruses of species C in areas where several outbreaks of vaccine-derived polioviruses occurred

Background

Poliomyelitis outbreaks due to pathogenic vaccine-derived polioviruses (VDPVs) are threatening and complicating the global polio eradication initiative. Most of these VDPVs are genetic recombinants with non-polio enteroviruses (NPEVs) of species C. Little is known about factors favoring this genetic macroevolution process. Since 2001, Madagascar has experienced several outbreaks of poliomyelitis due to VDPVs, and most of VDPVs were isolated in the south of the island. The current study explored some of the viral factors that can promote and explain the emergence of recombinant VDPVs in Madagascar.

Methods

Between May to August 2011, we collected stools from healthy children living in two southern and two northern regions of Madagascar. Virus isolation was done in RD, HEp-2c, and L20B cell lines, and enteroviruses were detected using a wide-spectrum 5ʹ-untranslated region RT-PCR assay. NPEVs were then sequenced for the VP1 gene used for viral genotyping.

Results

Overall, we collected 1309 stools, of which 351 NPEVs (26.8%) were identified. Sequencing revealed 33 types of viruses belonging to three different species: Enterovirus A (8.5%), Enterovirus B (EV-B, 40.2%), and Enterovirus C (EV-C, 51.3%). EV-C species included coxsackievirus A13, A17, and A20 previously described as putative recombination partners for poliovirus vaccine strains. Interestingly, the isolation rate was higher among stools originating from the South (30.3% vs. 23.6%, p-value = 0.009). EV-C were predominant in southern sites (65.7%) while EV-B predominated in northern sites (54.9%). The factors that explain the relative abundance of EV-C in the South are still unknown.

Conclusions

Whatever its causes, the relative abundance of EV-C in the South of Madagascar may have promoted the infections of children by EV-C, including the PV vaccine strains, and have favored the recombination events between PVs and NPEVs in co-infected children, thus leading to the recurrent emergence of recombinant VDPVs in this region of Madagascar.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07826-0.

Identification of enteroviruses along Lake Victoria shoreline - a potential indicator of sewage pollution

Enteric viruses are mainly transmitted by the faecal-oral route and have been linked to several diseases including gastroenteritis and respiratory infections. Their presence in surface waters has been exacerbated by pollution from a variety of point sources such as sewage discharge. We studied the occurrence of enteroviruses in water samples from Lake Victoriain Kenya to investigate if there was a link between sewage pollution and detection of enteroviruses (EVs) to build a baseline for an enteric viruses monitoring platform for this region. We analysed 216 samples collected over 6 months from six different locations along the Homa Bay Pier. The six sampling locations comprised of three sites (P3, P5, P6) located <500 m from a local sewage treatment plant and pit latrines while three other sites (P1, P2, P4) were located at approximately 0.5 to 3 Km. EVs were concentrated using glass wool adsorption elution protocol and identified using the nested reverse transcription-polymerase chain reaction. The odds ratio was performed to determine whether the location of the sources of sewage pollution near the lake was associated with the EVs contamination. Five out of 108 (5 %) samples collected from the sites (P3, P5 and P6 were EV positive, while 2 % (2/108) of samples from P1, P2 and P4 were EV positive. The presence of the EVs was associated with the distance from the possible sources of faecal contamination (odds ratio 20.28 and 4.86, confidence interval 2.42, and 0.95) for pit latrines and the sewage treatment plant respectively. The result from this study indicates that sewage discharge at the shoreline of Lake Victoria may have been the source of EVs contamination. Data from this study could significantly contribute to informing risk management on sewage pollution in Lake Victoria and it is important to continue monitoring this lake for potentially pathogenic enteric viruses.

Further considerations about "Detection and identification of enteroviruses circulating in children with acute gastroenteritis in Pará State, Northern Brazil (2010-2011)"

On the detection and identification of enteroviruses circulating in children with acute gastroenteritis in Brazil: reply to Luchs, A. Comments on Detection and identification of enteroviruses circulating in children with acute gastroenteritis in Pará State, Northern Brazil (2010–2011).

Coxsackievirus B4: an underestimated pathogen associated with a hand, foot, and mouth disease outbreak

In order to discover the causes of a coxsackievirus B4 (CV-B4)-associated hand, foot, and mouth disease (HFMD) outbreak and to study the evolutionary characteristics of the virus, we sequenced isolates obtained during an outbreak for comparative analysis with previously sequenced strains. Phylogenetic and evolutionary dynamics analysis was performed to examine the genetic characteristics of CV-B4 in China and worldwide. Phylogenetic analysis showed that CV-B4 originated from a common ancestor in Shandong. CV-B4 strains isolated worldwide could be classified into genotypes A-E based on the sequence of the VP1 region. All CV-B4 strains in China belonged to genotype E. The global population diversity of CV-B4 fluctuated substantially over time, and CV-B4 isolated in China accounted for a significant increase in the diversity of CV-B4. The average nucleotide substitution rate in VP1 of Chinese CV-B4 (5.20 × 10^-3 substitutions/site/year) was slightly higher than that of global CV-B4 (4.82 × 10^-3 substitutions/site/year). This study is the first to investigate the evolutionary dynamics of CV-B4 and its association with an HFMD outbreak. These findings explain both the 2011 outbreak and the global increase in CV-B4 diversity. In addition to improving our understanding of a major outbreak, these findings provide a basis for the development of surveillance strategies.

Human Enterovirus Diversity by Next-Generation Sequencing Analysis in Urban Sewage Samples From Buenos Aires Metropolitan Area, Argentina: A Retrospective Study

Human Enteroviruses (hEVs) are responsible for a wide variety of human diseases. During hEVs infection, virions are excreted in human feces and the fecal-oral route is the primary pathway for person-to-person transmission. Sewage surveillance could help in monitoring hEVs circulation and describing their diversity in a specific population. In this study, sewage samples collected in Buenos Aires Metropolitan Area (Argentina) were retrospectively studied through an amplicon-deep sequencing approach and phylogenetic analyses to characterize hEVs spread. We identified 17 different hEVs types belonging to A, B, and C species. To the best of our knowledge, this is the first report in Buenos Aires for 7 identified hEV-C types. Phylogenetic analyses suggest several introductions of coxsackievirus B4, echovirus 1, and echovirus 9 in the country, along with the national spread reached by some variants. Besides, well-supported monophyletic groups of Argentine, Uruguayan, and Brazilian strains unveiled regional circulation patterns for some variants. These results extend our knowledge about hEVs circulation in Buenos Aires and might exhort authorities to implement more active sewage surveillance in the region.

Clinical, epidemiological, and molecular aspects of picornaviruses (entero, parecho) in acute gastroenteritis: A study from Pune (Maharashtra), Western India

Among enteric viruses, rotavirus A (RVA), norovirus (NoV), adenovirus, and astrovirus (AstV) are the major etiological agents associated in acute gastroenteritis. The present study highlights, clinical, epidemiological, and molecular aspects with respect to RVA, NoV, enterovirus (EV), and human parechovirus (HPeVs) in sporadic cases (n = 305) of acute gastroenteritis, Pune (Maharashtra), Western India. Detection of RVA was carried out by enzyme-linked immunosorbent assay, NoV, EV, and HPeVs by reverse transcription PCR. Prevalence of 36.06%, 20.32%, 14.09%, 3.93%, respectively was observed for RVA, EV, HPeVs, and NoV along with coinfections. Infections occurred in children less than 2 years old, with peak infections within 12 months age. The disease severity in RV infections was found high (70.90%) with severe disease, followed by EV (62.9%), NoV (58.33%), and HPeV (44.58%). Predominant strains of RV G1P[8], G2P[4] types with unusual G9P[4], NoV Genogroup II of genotype 4 strains and multiple EV types with EV-B species, E14 and E17 and two novel EV-75, EV-107 types were detected. Circulation of heterogeneous HPeV genotypes (HPeV1-5, 7, 8, 13, 14, 16) with predominance of HPeV-1 was noticed. Changing trends in circulation of a rare HPeV-2 genotype, with emerging and reemerging strains was noted. The study highlights association of RVA, NoV, EV, and HPeV and their mono-infections, genotype distribution, and changing trends in acute gastroenteritis, and added more knowledge on rota and nonrota enteric viruses in acute gastroenteritis. More such studies in rota vaccinated era are required across the country, as Indian rotavirus vaccine has been implemented under the National Immunization program.

Incidence of enterovirus in patients with acute gastroenteritis

Enteroviruses (EV) have been linked to lymphocytic meningitis and exanthems, but they may also be involved in acute gastroenteritis (AGE), a condition whose aetiological agent often remains unidentified. In this work 1214 samples from individuals with AGE were studied with the aim of establishing the incidence of EV. The samples were collected between September and December in three different years and subjected to real-time genomic amplification in order to determine the viral load (VL). Of the 1214 samples studied, infection by a single virus was found in 328 cases (27%) and coinfection in 69 (5.7%). While adenoviruses (AdV) were the most frequent (14.8% of total), EV were present in 126 (10.4%) of the individuals tested. Of the 126 EV-positive samples, this virus was found as a single infection and coinfection in 76 (6.3%) and 50 (4.1%) cases, respectively. VL for EV was 5.58±1.51 log copies/ml (range 3.73-9.69) in the former and 6.27±1.75 (range 3.73-10.5) (p=0.02) in the latter. EV were identified in 97 children under 5 (16.9%) and in 29 (4.5%) patients over 5. Patients less than 5 years showed a higher VL that those more than 5 years age [6.08±1.57 (range 3.82-9.69) vs. 5.07±1.53 (range 3.73-10.58); (p=0.002)]. There was a high incidence of EV in AGE patients, and they were more frequent in those under 5, where they were found to replicate more efficiently. These results therefore indicate that testing for EV should be included in the diagnosis of AGE.

Molecular Epidemiological, Serological, and Pathogenic Analysis of EV-B75 Associated With Acute Flaccid Paralysis Cases in Tibet, China

Enterovirus B75 (EV-B75) is a newly identified serotype of the enterovirus B species. To date, only 112 cases related to EV-B75 have been reported worldwide, and research on EV-B75 is still limited with only two full-length genome sequences available in GenBank. The present study reported seven EV-B75 sequences from a child with acute flaccid paralysis and six asymptomatic close contacts in Shigatse, Tibet. Phylogenetic analysis revealed that the Tibetan strain was possibly imported from neighboring India. Seroepidemiological analyses indicated that EV-B75 has not yet caused a large-scale epidemic in Tibet. Similarity plots and boot scanning analyses revealed frequent intertypic recombination in the non-structural region of all seven Tibet EV-B75 strains. All seven Tibetan strains were temperature-sensitive, suggesting their poor transmissibility in the environment. Overall, though the seven Tibetan strains did not cause large-scale infection, prevention and control of the novel enterovirus cannot be underestimated.

Molecular typing and characterization of a novel genotype of EV-B93 isolated from Tibet, China

EV-B93 is a novel serotype within the Enterovirus B species and is uncommon worldwide. Currently, only one full-length genomic sequence (the prototype strain) has been deposited in the GenBank database. In this study, three EV-B93 were identified, including one from an acute flaccid paralysis (AFP) patient (named 99052/XZ/CHN/1999, hereafter XZ99052) and two from healthy children (named 99096/XZ/CHN/1999 and 99167/XZ/CHN/1999, hereafter XZ99096 and XZ99167, respectively) from Tibet in 1999 during the polio eradication program. The identity between the nucleotide and amino acid sequences of the Tibet EV-B93 strain and the EV-B93 prototype strain is 83.2%–83.4% and 96.8%–96.9%, respectively. The Tibet EV-B93 strain was found to have greater nucleotide sequence identity in the P3 region to another enterovirus EV-B107 as per a phylogenetic tree analysis, which revealed that recombination occurred. Seroepidemiology data showed that EV-B93 has not produced an epidemic in Tibet and there may be susceptible individuals. The three Tibet EV-B93 strains are temperature-resistant with prognosticative virulence, suggesting the possibility of a potential large-scale outbreak of EV-B93. The analyzed EV-B93 strains enrich our knowledge about this serotype and provide valuable information on global EV-B93 molecular epidemiology. What is more, they permit the appraisal of the serotype's potential public health impact and aid in understanding the role of recombination events in the evolution of enteroviruses.

Enteric Viral Co-Infections: Pathogenesis and Perspective

Enteric viral co-infections, infections involving more than one virus, have been reported for a diverse group of etiological agents, including rotavirus, norovirus, astrovirus, adenovirus, and enteroviruses. These pathogens are causative agents for acute gastroenteritis and diarrheal disease in immunocompetent and immunocompromised individuals of all ages globally. Despite virus–virus co-infection events in the intestine being increasingly detected, little is known about their impact on disease outcomes or human health. Here, we review what is currently known about the clinical prevalence of virus–virus co-infections and how co-infections may influence vaccine responses. While experimental investigations into enteric virus co-infections have been limited, we highlight in vivo and in vitro models with exciting potential to investigate viral co-infections. Many features of virus–virus co-infection mechanisms in the intestine remain unclear, and further research will be critical.

Enterovirus infections in pediatric patients hospitalized with acute gastroenteritis in Chiang Mai, Thailand, 2015-2018

Background

Infection with viruses especially rotavirus, norovirus, astrovirus, and adenovirus has been known to be a major cause of acute gastroenteritis in children under 5 years of age globally, particularly in developing countries. Also, some genotypes of enteroviruses (EVs) have been reported to be associated with gastroenteritis. This study is aimed to investigate the prevalence and genotype diversity of EV in children admitted to hospitals with acute gastroenteritis.

Methods

A total of 1,736 fecal specimens were collected from children hospitalized with diarrhea in Chiang Mai, Thailand from 2015 to 2018. All specimens were tested for the presence of EV by RT-PCR of the 5' untranslated region. The genotypes of EV were further identified by nucleotide sequencing and phylogenetic analysis of the viral protein 1 (VP1) gene.

Results

EV was detected in 154 out of 1,736 specimens (8.9%) throughout the study period. The prevalence of EV detected in 2015, 2016, 2017, and 2018 was 7.2%, 9.0%, 11.2%, and 8.6%, respectively. EV was detected all year round with a high prevalence during rainy season in Thailand. Overall, 37 genotypes of EV were identified in this study. Among these, coxsackievirus (CV)-A24 and CV-B5 (7.5% each), and EV-C96 (6.8%) were the common genotypes detected.

Conclusion

This study demonstrates the prevalence, seasonal distribution, and genotype diversity of EV circulating in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand during the period 2015 to 2018.

Enteroviruses in gastrointestinal diseases

Gastrointestinal diseases including diarrhoea constitute a major cause of morbidity and mortality in infants and young children especially in developing countries. Worldwide deaths among all ages due to diarrhoea during 2015 were estimated to be about 1.31 million, diarrhoeal deaths in children below 5 years of age being 499 000. Rotavirus accounted for about 200 000 deaths. Although diarrhoeal deaths decreased significantly during the last two decades, they still represent the third largest cause of infantile deaths. Several bacterial, viral, parasitic, fungal and non-infectious diarrhoea causing agents have been identified, but 30% to 40% of diarrhoeal cases remain undiagnosed. Enteroviruses transmit by the faecal-oral route and replicate first in intestinal cells before spreading to the target organ. They have been associated with diarrhoea in a few studies, but their causative role in diarrhoea in humans has not been systematically demonstrated. In view of the recent demonstration that enteroviruses cause diarrhoea in newborn mice pups, thus validating Koch's postulates, the purpose of this review is to emphasise the importance of recognising enteroviruses as major gastrointestinal pathogens associated with acute and persistent diarrhoea and non-diarrhoeal increased frequency of bowel movements in infants, young children and adults. Our studies and several other subsequent studies reported from different countries should stimulate strategies to reduce the burden of infantile gastrointestinal disease, which has hitherto remained unaddressed.

A Reverse Transcription-Polymerase Spiral Reaction (RT-PSR)-Based Rapid Coxsackievirus A16 Detection Method and Its Application in the Clinical Diagnosis of Hand, Foot, and Mouth Disease

Hand, foot, and mouth disease (HFMD) is a common viral illness affecting infants and children that is usually caused by Coxsackievirus A16 (CVA-16). To diagnose HFMD, we developed a method for rapid detection of CVA-16 based on reverse transcription-polymerase spiral reaction (RT-PSR). We used two pairs of primers that specifically recognize the conserved sequences of VP1 coding region of CVA-16, and template RNA was reverse transcribed and amplified in a single tube under isothermal conditions, total reaction time could be reduced to less than 40 min. The detection limit of this method was between 2.4 × 10² and 2.4 × 10¹ copies/μl with excellent specificity. To test the clinical applicability of the method, 40 clinical stool samples were analyzed using RT-PSR and quantitative reverse transcription-polymerase chain reaction, and comparison showed that the coincidence rate was 100%. Compared with other similar detection methods, RT-PSR requires less time, simpler operation, and lower cost. These results prove that our novel, simple, and reliable isothermal nucleic acid testing assay has potential application for clinical detection of CVA-16.

Enterovirus detection and serotyping of fecal material collected from three children living on the outskirts of Belém city, Amazon region, Brazil, during the first 3 years of life (1983-1986)

In the current investigation, fecal material was obtained during a community-based longitudinal study conducted from 1983 to 1986. This study consisted of 71 children aged newborn to 3 years. A total of 216 samples from three of these children were screened by real-time quantitative polymerase chain reaction (RT-qPCR) for the presence of enteroviruses, and positive samples were serotyped by VP1 and VP3 sequencing of the viral genome. Of these, 12 (5.6%) came from symptomatic cases, and the remaining asymptomatic cases were collected fortnightly during the 3 years of study. A positivity of 63.4% (137/216) was obtained by RT-qPCR, with 58.3% (7/12) in relation to the symptomatic group and 63.7% (130/204) in relation to the asymptomatic group. The 137 positive samples were inoculated into the RD, HEp2C, and L20B cell lines, and the cytopathic effect was observed in 37.2% (51/137) samples. It was also possible to identify 40.9% (56/137), between isolated (n = 46) and nonisolated (n = 10). Enterovirus serotype diversity (n = 25) was identified in this study, with the predominant species being B (80.3%), followed by C (16.1%) and A (3.6%). Cases of reinfection by different serotypes were also observed in the three children studied. Analyses involving different age groups of these minors confirmed that the most affected age was between 12 to 24 months, with a prevalence of 77.6% (52/67). The enterovirus (EV) circulated in the 3 years of research, showed peaks in some months, without defined seasonality. This study demonstrated a high circulation and serotype diversity of EV in fecal samples, collected over 30 years ago. This endorsed the evaluation of important points of the epidemiology of these viruses, such as the presence of coinfection and reinfection of the same individual by different circulating serotypes. Understanding the frequency and duration of EV infections is important in determining their association with persistent diarrhea.

A case control study on the prevalence of enterovirus in children samples and its association with diarrhea

Some serotypes of enterovirus (EV) may lead to transient and symptomatic gastrointestinal infections while others are commensal residents of the human gut. To determine whether certain EV types are more often associated with diarrhea, we conducted a preliminary study on the prevalence of EV serotypes and common diarrhea viruses in fecal samples of diarrhea children and healthy controls. EV was tested with one step nest polymerase chain reaction and typed by direct sequencing while common causative diarrhea viruses rotavirus (RV), norovirus (NoV), adenovirus (AdV), bocavirus (HBoV), and astrovirus (AstV) were screened with multiplex PCR assays. Human Rhinovirus (HRV) and human EVs that were present in both groups were further quantified and their odds ratios (OR) were calculated. Enteric pathogens were detected in 89 (32.6%) of 273 children with diarrhea and included human EVs (51, 18.68%), HRV (32, 11.72%), RV (38, 13.92%), AdV (24, 8.79%), NoVGII (16, 8.79%), HBoV (8, 2.93%) and AstV (3, 1.09%). Potential enteric pathogens were found in 25 (6.93%) of 361 healthy controls and included human EV (59, 16.34%), HRV (8, 2.22%), RV (1, 0.28%), NoVGII (5, 1.39%), AstV (2, 0.55%), AdV (16, 4.43%) and HBoV (1, 0.28%). In addition, EV71, echovirus 3,9,14,25 and coxsackievirus A14 existed in healthy controls only, while HRV, echovirus11,18, coxsackievirus A2,4,6 and B2,4 were found in both patients and healthy controls. OR assessment confirmed a strong association of HRV (P < 0.001) and a weak one for echovirus 11 and coxsackievirus A6 with diarrhea (P > 0.05). Our results indicate the diversity of EV serotypes in diarrhea and healthy control groups varies, and the potential etiological role of HRV in diarrhea.

Molecular diversity of Coxsackievirus A10 circulating in the southern and northern region of India [2009-17]

Non-Polio EnteroViruses (NPEV) are one of the known causative agents of Acute Flaccid Paralysis (AFP). In the present study, we identified, sequenced and characterized the complete genome of sixty-five Coxsackievirus-A10, an NPEV. These were isolated from stool specimens of AFP cases from Bihar, Karnataka, Kerala, and Uttar Pradesh (UP) states of India. Evolutionary analysis of complete genome (7420 nucleotides) and VP1 gene (894 nucleotides) demonstrates that there are four different intra-typic strains circulating in India which were dissimilar to Chinese strains. First intratypic strain circulating in UP, Bihar, and Karnataka; second in UP and Karnataka; third in UP and Bihar and; fourth was restricted only to Kerala state. The divergence of Kerala strain with respect to all other circulating strain of UP, Bihar and Karnataka states in India is 24%, 24.9%, and 24.4% respectively. Recombinations were observed between few of these strains which might be one of the factors of the observed intra-typic diversity. ARTICLE SUMMARY LINE: We report the identification, characterization and phylogenetic analysis of sixty-five Non-Polio Enterovirus (NPEV) isolates, performed during the year 2009-17, causing acute flaccid paralysis in pediatric cases with their divergences and recombinations from four states of India.

Molecular characterization of echovirus 12 strains isolated from healthy children in China

Human echovirus 12 (E-12) belongs to the enterovirus B species. To date, only one full-length genome sequence of E-12 (prototype strain Travis) is available in the GenBank database. This study determined the complete sequence of three E-12 strains, which were isolated from the stools of three healthy children in Yunnan, China, in 2013. We revealed that the three Yunnan E-12 strains had only 80.8-80.9% nucleotide identity and 96.4-96.8% amino acid identity with the Travis strain based on pairwise comparisons of the complete genome nucleotide and amino acid sequences. The three Yunnan strains shared 99.7% nucleotide identity and 99.1-99.5% amino acid similarity. Phylogenetic and similarity plot analyses showed that intertypic recombination occurred in the non-structural regions of the three Yunnan E-12 strains. This is the first report of the complete genome sequence of E-12 in China and it enriches the complete genome sequences of E-12 in the GenBank database.

Contribution of the FilmArray® Gastrointestinal Panel in the laboratory diagnosis of gastroenteritis in a cohort of children: a two-year prospective study

This study represents a 2-year picture of the epidemiology of enteric pathogens in children suffering from gastroenteritis using the FilmArray® Gastrointestinal Panel (FA-GP), a multiplex molecular assay that allows to simultaneously detect a large panel of pathogens independently of the etiological suspicion and to evaluate its potential contribution to the diagnosis compared to the conventional methods. A total of 1716 stool samples, collected from children with clinical suspicion of bacterial and/or viral gastroenteritis attending the University Hospital of Parma, was submitted to the FA-GP and, when an adequate aliquot was available, to electron microscopy (n = 1163) for virus detection and to an enterovirus-targeting real-time PCR (n = 1703). Specimens with positive results for Salmonella, Yersinia enterocolitica, Vibrio, diarrheagenic Escherichia coli/Shigella, Campylobacter, Plesiomonas shigelloides and/or parasites by the FA-GP were also submitted to conventional diagnostic methods. The FA-GP gave positive results in 958 (55.8%) cases, 64.8% from inpatients: 647 (67.5%) contained a single agent and 311 (32.5%) multiple agents, for a total of 1374 pathogens. Enteropathogenic E. coli, rotavirus, norovirus, toxigenic Clostridioides difficile, and sapovirus were the most commonly detected pathogens. A total of 812 additional agents (344 of which as single pathogen) was detected by the FA-GP and not included in the clinical suspicion. The overall recovery rate of the conventional methods from stools that resulted positive by the FA-GP was 38.6% for bacteria, 50% and 84.2% for Giardia intestinalis and Cryptosporidium, respectively, and ranged from 3.7% to 64.6% for viruses, if excluding all electron microscopy-negative astroviruses. Enterovirus, an agent not targeted by the FA-GP, was revealed in 9.6% (164/1703) of the examined samples, and in 52 cases it was the only agent detected. The results of this study allowed to extend the range of detectable pathogens independently of the clinical suspicion, to detect co-infections in almost one third of children positive for at least one agent and to show that conventional methods would have missed more than half of the enteric agents detected by the FA-GP.

Detection and genetic characterization of enterovirus strains circulating among children with acute gastroenteritis in Japan during 2014-2016

Of 972 stool samples collected from infants and children with acute gastroenteritis in six different regions (Hokkaido, Tokyo, Shizuoka, Kyoto, Osaka, and Saga) of Japan during 2-year period from July 2014 to June 2016, 63 samples (6.5%) determined to be positive for enterovirus by multiplex RT-PCR were subjected to genotype determination based on the partial VP1 region using the CODEHOP method. Sixty-two strains were succeeded in genotyping and seventeen EV types were identified. The majority of the studied strains belonged to EV-A (30 of 62; 48.4%) and EV-B (31 of 62, 50%) species, and the remaining strain was of the EV-D species. The most frequently detected type was Coxsackievirus A5 (CV-A5) in 2014-2015 while was CV-B5 in 2015-2016. This study provides an insight into the genetic diversity of EV with the predominance of EV-A and EV-B species in Japanese infants and children with acute gastroenteritis during 2014-2016.

Multiple enterovirus genotypes circulating in children hospitalized with acute gastroenteritis in Thailand

Enterovirus (EV) infection is widespread and can lead to a broad range of clinical symptoms, from mild to severe forms of disease. EVs are not always classified as pathogen and the epidemiological surveillance of EV infection in acute gastroenteritis cases in Thailand remains unexplored. This study aims to investigate the frequency, seasonality and molecular characteristics of EV circulating in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand from 2010 to 2014. A total of 1266 fecal samples were included in this study. RT-PCR amplification of the 5'UTR was used for EV screening and phylogenetic analysis of the VP1 sequence was performed for EV genotyping. EV was detected in 5.8% of infections (73 out of 1266). Based on VP1 sequence analysis, over half (50.8%) of the identified EV cases were caused by species C, and the next two most frequent were species B and A (35.4% and 13.8%, respectively). This study identified 28 different EV genotypes, EV-C96 and coxsackievirus A24 were the most frequent genotype detected (12.3% each). EV was detected throughout the year with an increase of detection rate in December-January and May-June. In conclusion, this study reported the prevalence of EV infection with a wide variety of EV genotypes in children with acute diarrhea.

Large-scale HFMD epidemics caused by Coxsackievirus A16 in Bangalore, India during 2013 and 2015

Hand foot and mouth disease (HFMD) is a relatively unreported disease in India. This study was undertaken to characterize the enterovirus type/s associated with two unexpectedly-massive epidemics that occurred in Bangalore, India in 2013 and 2015. Stool samples of 229 children with HFMD living in Northern and Southern areas of Bangalore were tested by RT-PCR; 189 (82.5%) were enterovirus positive. The Indian CV-A16 strains exhibited 98-99% sequence identity with those reported in France and China in the 5' untranslated region. BLAST and phylogenetic analyses of complete genomes of representative Indian isolates revealed that the 2015 epidemic was predominated by an inter-species recombinant between CV-A16 and coxsackievirus B5. The 2013 epidemic was primarily caused by nonrecombinant strains. The CV-A16 strains circulated in India since 2007 and phylogeographic analyses indicated imported cases in France and China. In conclusion, CV-A16-associated HFMD epidemics should be recognized as an emerging public health problem in India.

Case-Control Comparison of Enteric Viromes in Captive Rhesus Macaques with Acute or Idiopathic Chronic Diarrhea

Diarrhea is the major cause of non-research-associated morbidity and mortality affecting the supply of rhesus macaques and, potentially, their responses to experimental treatments. Idiopathic chronic diarrhea (ICD) in rhesus macaques also resembles ulcerative colitis, one form of human inflammatory bowel disease. To test for viral etiologies, we characterized and compared the fecal viromes from 32 healthy animals, 31 animals with acute diarrhea, and 29 animals with ICD. The overall fractions of eukaryotic viral reads were 0.063% for the healthy group, 0.131% for the acute-diarrhea group, and 0.297% for the chronic-diarrhea group. Eukaryotic viruses belonging to 6 viral families, as well as numerous circular Rep-encoding single-stranded DNA (CRESS DNA) viral genomes, were identified. The most commonly detected sequences were from picornaviruses, making up 59 to 88% of all viral reads, followed by 9 to 17% for CRESS DNA virus sequences. The remaining 5 virus families, Adenoviridae, Astroviridae, Anelloviridae, Picobirnaviridae, and Parvoviridae, collectively made up 1 to 3% of the viral reads, except for parvoviruses, which made up 23% of the viral reads in the healthy group. Detected members of the families Picornaviridae and Parvoviridae were highly diverse, consisting of multiple genera, species, and genotypes. Coinfections with members of up to six viral families were detected. Complete and partial viral genomes were assembled and used to measure the number of matching short sequence reads in feces from the 92 animals in the two clinical and the healthy control groups. Several enterovirus genotypes and CRESS DNA genomes were associated with ICD relative to healthy animals. Conversely, higher read numbers from different parvoviruses were associated with healthy animals. Our study reveals a high level of enteric coinfections with diverse viruses in a captive rhesus macaque colony and identifies several viruses positively or negatively associated with ICD.

Human enteroviruses associated with and without diarrhea in Thailand between 2010 and 2016

Non-bacterial acute gastroenteritis (AGE) associated with virus infection affects individuals living in developing countries, especially children. To investigate whether shedding of certain human enterovirus (EV) is more frequently detected in the stool of individuals with AGE of unknown etiology than individuals without AGE symptoms, we tested fecal samples collected from 2,692 individuals with diarrhea between January 2010 and December 2016. Samples were tested for rotavirus, norovirus, and EV by reverse-transcription polymerase chain reaction (RT-PCR) and adenovirus by PCR. EV-positive samples were subjected to sequencing and phylogenetic analysis to identify EV species and types. Findings were compared to EV found in 1,310 fecal samples from individuals without AGE who were diagnosed with hand, foot, and mouth disease (HFMD). While the majority of viruses identified in AGE consisted of human rotavirus (22.7%), norovirus (11.4%) and adenovirus (9.3%), we identified EV (6.2%) belonging mainly to species B, C, and rhinovirus. In contrast, >92% of EV found without AGE symptoms belonged to species A. Although AGE symptoms are not often attributed to EV infection, EV was associated with diarrhea of unknown etiology at least in 3.4% of AGE cases. While CV-A6 was most likely to be found in stools of HFMD patients, rhinovirus A and C were the two most common EV species associated with AGE. Elucidating group-specific EV infection in diseases with and without AGE will be useful in assisting identification, clinical management, and the surveillance of EV infection in the community.

Resistance of Enteric Viruses on Fomites

Human enteric viruses are associated with several clinical features, especially gastroenteritis. Large amounts of these viruses can be released in the environment and spread to people. Enteric viruses are nonenveloped viruses and have displayed good survival in the environment. They can be significantly resistant in food and water but also on fomites, and this is thought to play a role in transmission, leading to sporadic cases or outbreaks. The survival of enteric viruses on fomites relies on many factors including the virus itself, fomite properties, and extrinsic environmental factors such as temperature or relative humidity. Several reports in the literature have found an association with gastroenteritis cases or outbreaks and fomites naturally contaminated by enteric viruses. However, the study of virus survival following natural contamination is challenging, and most published studies are laboratory based, using experimental contamination. In addition, recent and detailed data on the resistance of each of the main enteric viruses on fomites are scarce. Many approaches, both physical and chemical, can be used to inactivate enteric viruses, the efficacy of which depends on the virus and the disinfection conditions.

Comparison of clinical and laboratory characteristics during two major paediatric meningitis outbreaks of echovirus 30 and other non-polio enteroviruses in Germany in 2008 and 2013

Viral meningitis is mainly caused by non-polio enteroviruses (NPEV). Large-scale data on the clinical characteristics between different outbreaks within the same region are lacking. This study aimed to analyse a possible influence of the circulating NPEV genotype on the disease outcome of affected children. A retrospective cohort study analysing two major outbreaks of NPEV meningitis in Germany in 2008 and 2013 was conducted in cooperation with the National Reference Centre for Poliomyelitis and Enteroviruses (NRC PE) and five German children's hospitals. A total of 196 patients with laboratory-confirmed NPEV meningitis were enrolled. In 2008, children with NPEV meningitis had significantly higher fever and showed more behavioural changes and less back pain. To better define typical findings in echovirus 30 (E-30) meningitis, patients were split into the following three groups: E-30 positive patients, patients with "Non E-30" infection and patients with "Untyped" NPEV infection. E-30 positive patients were significantly older and their disease course was more acute, with early admission to but also early discharge from hospital. E-30 positive patients showed a significantly higher rate of headache and meningism, and a lower rate of diarrhoea and clinically defined septicaemia when compared to the others. Regarding laboratory testing, E-30 positive patients presented with significantly elevated peripheral blood neutrophil counts when compared to patients with "Non E-30" or "Untyped" NPEV infection. In conclusion, E-30 meningitis in children shows a characteristic pattern of clinical features. To further characterise NPEV strains worldwide, continuous surveillance and typing of NPEV strains causing central nervous system disease is warranted.

Changes in enterovirus serotype constituent ratios altered the clinical features of infected children in Guangdong Province, China, from 2010 to 2013

Background

Enterovirus (EV)-related hand, foot, and mouth disease/herpangina (HFMD/HA) has been prevalent in Guangdong Province, China, since 2010.

Methods

Clinical data for EV-related HFMD/HA inpatients admitted to the Department of Paediatrics of Zhujiang Hospital from 2010 to 2013 were retrospectively reviewed. The corresponding EV serotypes were also determined by reverse transcription-polymerase chain reaction or BLAST analysis of the sequenced partial lengths of the viral protein1/5′-untranslated region.

Results

A total of 867 eligible inpatients admitted during 2010–2013 were included in the study. Of these, the serotype of the responsible EV was successfully identified in 824 cases. The incidence of enterovirus 71 (EV71) infection amongst pediatric HFMD/HA inpatients decreased dramatically from 55.5 % in 2010 to 8.1 % in 2013, with a similar decrease recorded for coxsackievirus A16 (CVA16). However, the incidence of non-EV71/CVA16 infection increased from 30.0 % in 2010 to 83.8 % in 2013. We noted that the types of infection caused by different EV serotypes varied: EV71 was responsible for 100 % of the paralysis cases (26/26), 84.6 % of the deaths (11/13), and 84.1 % of cases with severe central nervous system involvement (SCNSI) (74/88); echovirus contributed to 16.4 % of the deaths (2/13) and 4.4 % of the SCNSI cases; and coxsackievirus accounted for only 2.2 % of the SCNSI cases (2/90). The clinical features of HFMD/HA cases varied greatly during the time period examined, with drastic changes in the hospitalization rates (45.1, 63.7, 36.4, and 19.1 % for 2010, 2011, 2012, and 21013, respectively), mortality rates (2.3, 0.9, 2.5, and 0.0 %, respectively), paralysis (5.1, 1.2, 5.4, and 0.0 %, respectively), SCNSI (16.8, 7.1, 12.7, and 2.2 %, respectively), and acute respiratory infection (21.1, 22.0, 45.9, and 59.0 %, respectively).

Conclusions

The incidences of infection caused by different EV serotypes, along with the clinical features of HFMD/HA cases, changed drastically in Guangdong Province, China, from 2010 to 2013, with the biggest changes observed in 2013. The changed constituent ratios of the different EV serotypes might therefore be responsible for the differences in the observed clinical features of HFMD/HA during this period.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1690-0) contains supplementary material, which is available to authorized users.

Direct Detection and Identification of Enteroviruses from Faeces of Healthy Nigerian Children Using a Cell-Culture Independent RT-Seminested PCR Assay

Recently, a cell-culture independent protocol for detection of enteroviruses from clinical specimen was recommended by the WHO for surveillance alongside the previously established protocols. Here, we investigated whether this new protocol will show the same enterovirus diversity landscape as the established cell-culture dependent protocols. Faecal samples were collected from sixty apparently healthy children in Ibadan, Nigeria. Samples were resuspended in phosphate buffered saline, RNA was extracted, and the VP1 gene was amplified using WHO recommended RT-snPCR protocol. Amplicons were sequenced and sequences subjected to phylogenetic analysis. Fifteen (25%) of the 60 samples yielded the expected band size. Of the 15 amplicons sequenced, 12 were exploitable. The remaining 3 had electropherograms with multiple peaks and were unexploitable. Eleven of the 12 exploitable sequences were identified as Coxsackievirus A1 (CVA1), CVA3, CVA4, CVA8, CVA20, echovirus 32 (E32), enterovirus 71 (EV71), EVB80, and EVC99. Subsequently, the last exploitable sequence was identified as enterobacteriophage baseplate gene by nucleotide BLAST. The results of this study document the first description of molecular sequence data on CVA1, CVA8, and E32 strains present in Nigeria. The result further showed that species A enteroviruses were more commonly detected in the region when cell-culture bias is bypassed.

Enterovirus-related diarrhoea in Guangdong, China: clinical features and implications in hand, foot and mouth disease and herpangina

Background

A series of complications caused by enteroviruses, including meningitis, encephalitis, acute flaccid paralysis, acute cardiopulmonary failure, respiratory infection, and myocardial injury have been reported in hand, foot and mouth disease/herpangina (HFMD/HA). However, the complication of diarrhoea caused by enteroviruses has been neglected, and a summary of its clinical features and impact on HFMD/HA is unavailable.

Methods

We included inpatients with HFMD/HA admitted to the Paediatric Department of Zhujiang Hospital during 2009–2012. We summarised and compared clinical data for cases with and without diarrhoea, and determined enterovirus serotypes by reverse transcriptase polymerase chain reaction and genotyping based on a partial-length fragment of viral protein 1 or the 5’-untranslated region.

Results

There were 804 inpatients with HFMD/HA and 28 (3.5 %) presented with diarrhoea. Gastrointestinal symptoms were mild in most cases of diarrhoea (82.1 %), with high prevalence of no dehydration (82.1 %), short duration of diarrhoea (78.6 %) and watery stools (75.0 %). The prevalence of multi-organ dysfunction syndrome (10.7 vs 0.40 %) (p = 0.001), hepatic injury (14.3 vs 3.4 %) (p = 0.019), myocardial injury (21.4 vs 6.1 %) (p = 0.002) and convulsion (21.4 vs 7.2 %) (p = 0.016) was significantly higher in the diarrhoea than no diarrhoea group. There was no significant difference between the two groups regarding prevalence of death, altered consciousness, paralysis, central nervous system involvement, or acute respiratory infection.

Conclusions

Most patients with diarrhoea caused by enteroviruses circulating in Guangdong Province in 2009–2012 had mild or moderate gastrointestinal symptoms. Although enterovirus-related diarrhoea caused additional multi-organ dysfunction syndrome, hepatic injury and myocardial injury in children with HFMD/HA, timely intervention efficiently reduced disease severity and improved outcome.

Prevalence of rotavirus, norovirus and enterovirus in diarrheal diseases in Himachal Pradesh, India

Diarrheal diseases are responsible for a significant proportion of mortality and morbidity all around the globe. The contribution of viruses to gastroenteritis incidences in humans is well established. In the present study, we have studied the prevalence of rotavirus, norovirus and enterovirus in Himachal Pradesh, a north Indian state. A total of 287 (111 children and 176 adults) stool samples of gastroenteritis patients were screened for the viruses using RT-PCR method. 34.5 % samples were positive for the viral pathogens of gastroenteritis. Rotavirus was the predominant virus detected in the study with 49.5 and 14.8 % positivity in children and adults, respectively. Enterovirus was present in 5.6 % cases whereas norovirus had least prevalence (1.4 %). Co infection (rotavirus and enterovirus) was witnessed at the prevalence rate of 0.6 %. Among different age groups, the prevalence of studied viruses was highest in the children belonging to the age groups of <5 years. Rotavirus infections were found to be significantly associated with vomiting and trend of higher rates of fever and dehydration was seen in children along with diarrhea. Seasonal distribution shows circulation of diarrheagenic viruses throughout the year. This is the first report of prevalence of various diarrheagenic viruses circulating in this region. The outcome of the study from this cohort provides a baseline data which can be used to design the preventive strategies in the otherwise unexplored state of Himachal Pradesh.

Disease burden of enterovirus infection in Taiwan: Implications for vaccination policy

OBJECTIVES

This study aimed to assess the disease burden and economic impacts of human nonpolio enteroviruses (NPEV) and enterovirus A71 (EV-A71) infection in Taiwan.

MATERIALS AND METHODS

We included children under five years old (n=983,127-1,118,649) with ICD-9-CM codes 0740 (herpangina) or 0743 (hand-foot-and-mouth disease) from the 2006 to 2010 National Health Insurance Database. Severity of enterovirus infection was assessed from outpatient/emergency visits, hospitalization (with/without intensive care unit [ICU] admission), infection with severe complications, and death. We estimated medical costs and indirect costs from the societal perspective.

RESULTS

The annual rates of NPEV events for children under five years old ranged from 13.9% to 38.4%, of which 5.1-8.8% were hospitalized. EV-A71 accounted for 7.8% of all NPEV medical costs, but 79.1% of NPEV ICU costs. Travel costs and productivity loss of caregivers were $37.1 (range: $24.5-$64.7) million per year. These costs were not higher in the EV-A71 dominant year ($34.4 million) compared with those in the other years. Productivity losses resulting from premature mortality by NPEV infection were $0.8 (range: $0.0-$2.9) million per year, of which 96.3% were caused by EV-A71.

CONCLUSIONS

Diseases associated with NPEV other than EV-A71 were responsible for most of the medical expenses. In addition, caregiver productivity loss by high rates of NPEV infection impacted the society much more than medical costs. A multi-valent vaccine that includes EV-A71 and other serotypes, for example coxsackievirus A16, may be beneficial to the health of children in Taiwan.

Enterovirus Species B Bias of RD Cell Line and Its Influence on Enterovirus Diversity Landscape

Despite its widespread use in poliovirus isolation, studies show that most RD cell line isolates are species B enteroviruses (EB), it was therefore employed to further catalogue the EB diversity in two different regions of Nigeria. Concentrates of 18 environmental samples were inoculated into RD cell line. Isolates were subjected to PCR assays to detect enteroviruses, species C and B members and partial VP1 gene which was subsequently sequenced and used for identification and phylogenetic analysis. Isolates were further passaged in L20B cell line to detect polioviruses. Sixty-eight isolates were recovered from the 18 concentrates, all of which were positive for the enterovirus 5'-UTR screen. Thirteen of the 68 isolates were positive for the species C screen and replicated in L20B cell line, eleven of which also contained species B enteroviruses. Some of the mixed isolates were successfully typed, but as species B members. In all, isolates recovered in this study were identified as CVB5, E6, E7, E11, E13, E19, E20, E33, EVB75 and WPV3, while some could not be typed. Alongside the ten different enterovirus serotypes confirmed, results of this study document for the first time in Nigeria, EVB75. It showed the EB bias of RD cell line might indicate something much more fundamental in its biology. Finally, the finding of WPV3 in a region considered low risk for poliovirus emphasizes the need to expand poliovirus environmental surveillance to enable early detection of poliovirus silent circulation before occurrence of clinical manifestations.

An enzyme-linked immuno focus assay for rapid detection and enumeration, and a newborn mouse model for human non-polio enteroviruses associated with acute diarrhea

We have recently reported significant association of non-polio enteroviruses (NPEVs) with acute and persistent diarrhea (18-21% of total diarrheal cases), and non-diarrheal Increased Frequency of Bowel Movements (IFoBM-ND) (about 29% of the NPEV infections) in children and that the NPEV-associated diarrhea was as significant as rotavirus diarrhea. However, their diarrhea-causing potential is yet to be demonstrated in an animal model system. Since the determination of virus titers by the traditional plaque assay takes 4-7 days, there is a need for development of a rapid method for virus titer determination to facilitate active clinical research on enterovirus-associated diarrhea. The goal of this study is to develop a cell-based rapid detection and enumeration method and to demonstrate the diarrhea-inducing potential of purified and characterized non-polio enteroviruses, which were isolated from diarrheic children. Here we describe generation of monoclonal and polyclonal antibodies against purified strains belonging to different serotypes, and development of an enzyme-linked immuno focus assay (ELIFA) for detection and enumeration of live NPEV particles in clinical and purified virus samples, and a newborn mouse model for NPEV diarrhea. Plaque-purified NPVEs, belonging to different serotypes, isolated from children with diarrhea, were grown in cell culture and purified by isopycnic CsCl density gradient centrifugation. By ELIFA, NPEVs could be detected and enumerated within 12h post-infection. Our results demonstrated that Coxsackievirus B1 (CVB1) and CVB5 strains, isolated from diarrheic children, induced severe diarrhea in orally-inoculated 9-12 day-old mouse pups, fulfilling Koch's postulates. The methods described here would facilitate studies on NPEV-associated gastrointestinal disease.

Non-diarrhoeal increased frequency of bowel movements (IFoBM-ND): enterovirus association with the symptoms in children

OBJECTIVE

Infectious and non-infectious causes are associated with increased frequency of bowel movements (IFoBM). But, a viral aetiology to non-diarrhoeal IFoBM (IFoBM-ND) has not been described. Owing to an accidental infection by an echovirus 19 strain, persistent diarrhoea-associated virus, isolated from a child with persistent diarrhoea, DCR experienced persistent IFoBM-ND with an urgency to pass apparently normal stools more than once each day for about 3 months. A follow-up study was undertaken to determine the prevalence of IFoBM-ND, and association of non-polio enteroviruses (NPEVs) with the symptom in infants from birth to 2 years.

DESIGN

A cohort of 140 newborns was followed for 6 months to 2 years from birth for IFoBM-ND. Stool samples collected every 14 days were examined for NPEVs, rotavirus and other viral/bacterial agents for their possible association with IFoBM-ND and diarrhoea.

RESULTS

Of 403 NPEV infection episodes among 4545 oral polio vaccine strains-negative stool samples, approximately 29% were associated with IFoBM-ND (15% acute and 14% persistent), including resolution of 74% of constipation episodes, and 18% with diarrhoea, suggesting that about 47% of NPEV infection episodes in children below 2 years of age are associated with gastrointestinal symptoms. About 83% of IFoBM-ND episodes are associated with the NPEV infection and 17% of the episodes are of unknown aetiology.

CONCLUSIONS

NPEV is the single most frequently detected viral agent in children with IFoBM-ND and its association with the symptom is highly significant, warranting detailed investigations on the role of NPEVs in gastrointestinal diseases.

Molecular epidemiology of enterovirus B77 isolated from non polio acute flaccid paralytic patients in Pakistan during 2013

Human enteroviruses are associated with various clinical syndromes and severe neurological disorders. The aim of this study was to determine the molecular epidemiology of non polio enteroviruses and their correlation with acute flaccid paralysis (AFP) patients living in Khyber Pakhtunkhwa (KP) and Federally Administered Tribal Areas (FATA) of Pakistan. The stool samples collected from these patients were used for isolation of non polio enteroviruses (NPEVs). Out of 38 samples, 29 (76.3%) were successfully typed by microneutralization assay into eleven serotypes including echovirus (E)-3 (5.3%), E-7 (2.6%), E-11 (13.2%), E-12 (7.9%), E-13 (10.5%), E-20 (7.9%), E-27 (5.3%), E-29 (10.5%), E-30 (7.9%), E-33 (2.6%), coxsackievirus (CV) B5 (2.6%) and nine isolates (23.7%) remained untyped which were confirmed as NPEVs by real time RT-PCR. Complete VP1 genetic sequencing data characterized untypeable isolates into enterovirus B77 (EV-B77). Moreover, molecular phylogenetic analysis classified these viruses into two new genotypes having high genetic diversity (at least 17.7%) with prototype. This study provides valuable information on extensive genetic diversity of EV-B77 genotypes. Although, its association with neurological disorder has not yet been known but isolation of nine EV-B77 viruses from AFP cases highlights the fact that they may have a contributing role in the etiology of AFP. In addition, it is needed to establish enterovirus surveillance system and laboratory diagnostic facilities for early detection of NPEVs that may cause poliomyelitis like paralysis especially in the situation when we are at the verge of polio eradication.

Molecular surveillance of non-polio enterovirus infections in patients with acute gastroenteritis in Western India: 2004-2009

Acute gastroenteritis is a major cause of childhood morbidity and mortality worldwide. Rotavirus (RV) and Norovirus (NoV) are the leading cause of the disease. Despite the use of improved diagnostic methods a significant proportion of gastroenteritis cases remained undiagnosed. Though nonpolio enteroviruses (NPEVs) have been reported frequently in children with acute gastroenteritis, their etiologic role has not been established. To investigate the epidemiology of NPEVs in gastroenteritis cases which remained negative for leading causative agents, 955 RV and NoV negative stool specimens from children hospitalized for acute gastroenteritis were included in the study. A case control study was conducted which includes stool specimens from 450 children with gastroenteritis and 162 asymptomatic control subjects to determine the association of NPEVs with the disease. NPEV detection and typing was carried out by RT-PCR and sequencing. Presence of RV, NoV, Adenovirus, and Astrovirus was confirmed by ELISA or PCR/RT-PCR. Overall 14% NPEV prevalence was noted. The percentage of children with NPEV infection differed significantly between gastroenteritis and non-gastroenteritis patients (13.7% vs. 4.9%). NPEV was more prevalent among patients with gastroenteritis of undetectable etiology as compared to those detected positive for other viruses (17.9% vs. 7%) (P < 0.01). Genotyping of NPEV identified predominance of EV-B species (56.5%) followed by EV-C (16.7%), EV-A (13.8%) species and mixed NPEV infections (13%). These data support the association of NPEVs with acute gastroenteritis and highlights the clinical and epidemiological features of NPEV infections in patients with acute gastroenteritis from western India.

Non-polio enterovirus association with persistent diarrhea in children as revealed by a follow-up study of an Indian cohort during the first two years of life

BACKGROUND

We recently reported significant association of non-polio enteroviruses (NPEVs) with acute diarrhea in children. Persistent diarrhea (PD) remains a major cause of morbidity and mortality in infants below two years of age in developing countries. Understanding age-dependent frequency and duration of NPEV infections is important to determine their association with persistent diarrhea and disease burden.

OBJECTIVES

A cohort of 140 infants was followed for 6 months to 2 years of age to determine the frequency, duration, and association with PD of NPEV infections in comparison with rotavirus and other agents.

STUDY DESIGN

Stool samples were collected every 14 days, and diarrheal episodes and their duration were recorded. Enteroviruses were characterized by RT-PCR and VP1 gene sequence analysis, rotavirus by electropherotyping, and other agents by PCR.

RESULTS

Of 4545 samples, negative for oral polio vaccine strains, 3907 (85.96%) and 638 (14.04%) were NPEV-negative and NPEV-positive, respectively, representing 403 (8.87%) infection episodes. About 68% of NPEV infections occurred during the first year with every child having at least one episode lasting between four days and four months. Approximately 38% and 22% of total diarrheal episodes were positive for NPEV and RV, respectively. While about 18% of NPEV infection episodes were associated with diarrhea, 6% being persistent, 13% of total diarrheal episodes were persistent involving infections by monotype NPEV strains or sequential infections by multiple strains and other agents.

CONCLUSIONS

This is the first report revealing NPEVs as the single most frequently and persistently detected viral pathogen in every PD episode.

Isolation and identification of enteroviruses from sewage and sewage-contaminated water in Lagos, Nigeria

Studies have confirmed silent circulation of enteroviruses in the environment even in the absence of associated clinical conditions in the community. In this light, 26 samples of sewage and sewage-contaminated water serving selected high-risk communities in Lagos Nigeria were examined between June and September 2010. To concentrate virus particles in the sample, 480 μL of each sample was centrifuged at 3,000 rpm for 1 h at 4 °C. Subsequently, pellets were pooled, chloroform treated and further centrifuged at 1,500 rpm for 20 min at 4 °C. The water phase (concentrate) was then collected and stored at -20 °C. The concentrates were subsequently inoculated into RD and L20B cell lines. Recovered isolates were identified by real-time RT-PCR (rRT-PCR), serotyping, VP1 amplification, sequencing and phylogenetic analysis. Overall, 9 (34.6%) of the samples showed characteristic enterovirus cytopathic effect in RD cell line and were subsequently confirmed by pan-enterovirus rRT-PCR. The isolates were further identified by serotyping to include three E7, one E11 and one E13 isolates whilst four isolates were untypable. Further characterisation by VP1 sequencing confirmed the results of serotyping and rRT-PCR for all but isolate E13. Also, the four previously untypable isolates were identified to include two E19, one E20 and one E7 by VP1 sequencing. Results of the study confirmed circulation of Sub-Saharan Africa-specific enterovirus clades in the region, provide information on their molecular epidemiology and emphasise the need to combine methods of identification to enhance enterovirus surveillance.

Complete genome characterization of a novel enterovirus type EV-B106 isolated in China, 2012

Human enterovirus B106 (EV-B106) is a recently identified member of enterovirus species B. In this study, we report the complete genomic characterization of an EV-B106 strain (148/YN/CHN/12) isolated from an acute flaccid paralysis patient in Yunnan Province, China. The new strain had 79.2–81.3% nucleotide and 89.1–94.8% amino acid similarity in the VP1 region with the other two EV-B106 strains from Bolivia and Pakistan. When compared with other EV serotypes, it had the highest (73.3%) VP1 nucleotide similarity with the EV-B77 prototype strain CF496-99. However, when aligned with all EV-B106 and EV-B77 sequences available from the GenBank database, two major frame shifts were observed in the VP1 coding region, which resulted in substantial (20.5%) VP1 amino acid divergence between the two serotypes. Phylogenetic analysis and similarity plot analysis revealed multiple recombination events in the genome of this strain. This is the first report of the complete genome of EV-B106.

Molecular epidemiology of human enterovirus associated with aseptic meningitis in Shandong Province, China, 2006-2012

Background

Human enteroviruses (HEVs) are common causes of acute meningitis. However, there is limited information about HEV associated with aseptic meningitis in mainland China because it has not been classified as a notifiable disease.

Objectives

To characterize the HEVs associated with sporadic aseptic meningitis in China and to analyze their genetic features.

Study Design

Cerebrospinal fluid, throat swab and feces specimens were collected from patients with aseptic meningitis in 5 sentinel hospitals in Shandong Province, China between 2006 and 2012. Virological investigation (viral isolation and molecular identification) and phylogenetic analysis were performed.

Results

A total of 437 hospitalized patients were reported, and enteroviruses were detected in the specimens from 84 patients (19.2%) and were identified into 17 serotypes. The nine main serotypes were echovirus (E) 30 (27.4%), EV71 (13.1%), coxsackievirus (CV) B1 (9.5%), CVB3 (7.1%), CVB5 (7.1%), E6 (7.1%), E9 (7.1%), CVA9 (6.0%), and CVA10 (3.6%). Monthly distribution of isolated enteroviruses revealed a major peak in summer-fall season and a small second peak in winter constituted totally by EV71. Sequence analysis on VP1 coding region suggested Shandong strains had great genetic divergence with isolates from other countries.

Conclusions

Multiple serotypes were responsible for enterovirus meningitis in mainland China. Aseptic meningitis caused by EV71 and coxsackie A viruses–the predominant pathogens for the hand, foot, and mouth disease–is currently an important concern in mainland China.