Viruses causing childhood diarrhoea in the developing world. Curr Opin Infect Dis. 2009;22:477-482. [PMID: 19633550 DOI: 10.1097/qco.0b013e328330662f]

Navigating Viral Gastroenteritis: Epidemiological Trends, Pathogen Analysis, and Histopathological Findings

BACKGROUND

Gastroenteritis is a common cause of morbidity and mortality globally. Its cause encompasses a spectrum of agents, including viruses, bacteria, parasites, toxins, and drugs. Viruses account for a considerable portion of gastroenteritis cases across all age groups, typically presenting with symptoms like nausea, vomiting, diarrhea, dehydration, anorexia, and weight loss. While sporadic cases occur, viral gastroenteritis is more frequently observed in outbreaks within closely knit communities such as daycare facilities, nursing homes, and cruise ships. Therefore, it becomes necessary to determine when healthcare providers should consider this condition in their differential diagnosis and to develop the most effective strategy to confirm the diagnosis.

METHODS

De-identified data of patients with gastroenteritis were collected over a five-year period utilizing the Patient Cohort Explorer, an electronic health record at the University of Mississippi Medical Center. Confirmatory laboratory tests employed the BioFire® FilmArray® multiplex polymerase chain reaction for gastrointestinal pathogens. Out of the 22 most common agents associated with gastroenteritis, only viral pathogens, specifically adenovirus, astrovirus, norovirus, rotavirus, and sapovirus, were included in the analysis. When available, histopathology was reviewed.

RESULTS

Among the various causes of gastroenteritis, both infectious and non-infectious, our findings revealed that 25.46% of the cases were linked to viral pathogens. This included a significantly higher percentage of pediatric patients (72.73%) when compared to adults (27.07%), with a p-value of 0.015. Norovirus genogroups I and II emerged as the most frequently detected viruses across all age groups, with a significant prevalence among adults. No discernible gender-based differences were observed. The histopathological findings included inflammation, ulceration, erosion, architectural distortion, and the pathognomonic viral inclusion bodies associated with adenovirus.

CONCLUSION

Our comprehensive analysis of viral gastroenteritis cases highlights the substantial burden of this condition, particularly among pediatric patients. Norovirus emerges as a prevalent culprit which emphasizes the importance of vigilant surveillance and timely diagnosis, especially in settings where outbreaks are common.

A Roadmap for Building Waterborne Virus Traps

Outbreaks of waterborne viruses pose a massive threat to human health, claiming the lives of hundreds of thousands of people every year. Adsorption-based filtration offers a promising facile and environmentally friendly approach to help provide safe drinking water to a world population of almost 8 billion people, particularly in communities that lack the infrastructure for large-scale facilities. The search for a material that can effectively trap viruses has been mainly driven by a top-down approach, in which old and new materials have been tested for this purpose. Despite substantial advances, finding a material that achieves this crucial goal and meets all associated challenges remains elusive. We suggest that the road forward should strongly rely on a complementary bottom-up approach based on our fundamental understanding of virus interactions at interfaces. We review the state-of-the-art physicochemical knowledge of the forces that drive the adsorption of viruses at solid-water interfaces. Compared to other nanometric colloids, viruses have heterogeneous surface chemistry and diverse morphologies. We advocate that advancing our understanding of virus interactions would require describing their physicochemical properties using novel descriptors that reflect their heterogeneity and diversity. Several other related topics are also addressed, including the effect of coadsorbates on virus adsorption, virus inactivation at interfaces, and experimental considerations to ensure well-grounded research results. We finally conclude with selected examples of materials that made notable advances in the field.

Epidemiology of Human Adenovirus in Pakistani Children Hospitalized with Community-Acquired Gastroenteritis under the Age of Five Years

Acute gastroenteritis is the major cause of morbidity and mortality among infants and children around the globe. Along with other enteropathogens, human adenovirus (HadV) is a major etiological agent associated with diarrhea in young children. However, information about the epidemiology of Adenoviruses in Pakistan is limited or has not been reported. A total of 1082 stool samples were collected from patients with acute gastroenteritis under the age of five years with symptoms of diarrhea, vomiting, nausea, and abdominal cramps who visited Benazir Bhutto Hospital Rawalpindi and Children's hospital in Lahore of Punjab Province in Pakistan. Of this, 384 cases with no blood in their stool, negative for Rotavirus, and under the age of five years were recruited in this study. Human Adenoviruses were isolated in the human epithelial HEp-2 cell line. Furthermore, adenovirus antigen detection was carried out by an enzyme-linked immunosorbent assay (ELISA), and then all positive and negative samples were confirmed by nested PCR. After inoculating a clear stool supernatant on HEp-2 cell lines, we observed a positive cytopathic effect in 65 (16%) cases. Using an enzyme-linked immunosorbent assay, HAdV antigens were detected in 54 (14.06%) of the clear supernatant from gastroenteritis cases. However, HAdV hexon coding regions were amplified in 57 (14.80%) fecal samples, mainly from patients ≤24 months of age. The findings of this study suggest that adenovirus circulates significantly in the children population under the age of five years and may be the potential etiological factor of acute gastroenteritis in the mentioned cities. This study provides baseline data about the possible role of adenovirus in causing viral diarrhea in children. Further large-scale epidemiological surveys are recommended to better understand disease burden, etiological agents, and its clinical impact across the country.

Human adenoviruses: A suspect behind the outbreak of acute hepatitis in children amid the COVID-19 pandemic

As of 10 May 2022, at least 450 cases of pediatric patients with acute hepatitis of unknown cause have been reported worldwide. Human adenoviruses (HAdVs) have been detected in at least 74 cases, including the F type HAdV41 in 18 cases, which indicates that adenoviruses may be associated with this mysterious childhood hepatitis, although other infectious agents or environmental factors cannot be excluded. In this review, we provide a brief introduction of the basic features of HAdVs and describe diseases caused by different HAdVs in humans, aiming to help understand the biology and potential risk of HAdVs and cope with the outbreak of acute child hepatitis.

CrAssphage as an indicator of human-fecal contamination in water environment and virus reduction in wastewater treatment

Viral indicators of human-fecal contamination in wastewaters and environmental waters have been getting much attention in the past decade. Cross-assembly phage (crAssphage) is the most abundant DNA virus in human feces. Recently, the usefulness of crAssphage as a microbial source tracking and water quality monitoring tool for human-fecal contamination has been highlighted. Here, we conducted a comprehensive review on crAssphage in water, focusing on detection methodology, concentration range in various waters and wastewaters, specificity to human-fecal contamination, and reduction in wastewater treatment systems. This review highlights that crAssphage is globally distributed in wastewaters and various fecal-contaminated water bodies at high concentrations without seasonal fluctuations. CrAssphage is highly specific to human-fecal contamination and is rarely found in animal feces. It also has a good potential as a performance indicator to ensure virus reduction in wastewater treatment systems. Accordingly, crAssphage could be an effective tool for monitoring of human-fecal contamination and potential presence of fecal pathogenic microbes in environmental waters. Bridging the research gaps highlighted in this review would make crAssphage a powerful tool to support the control of water-related health risks.

Recent Advances in Early Diagnosis of Viruses Associated with Gastroenteritis by Biosensors

Gastroenteritis, as one of the main worldwide health challenges, especially in children, leads to 3–6 million deaths annually and causes nearly 20% of the total deaths of children aged ˂5 years, of which ~1.5 million gastroenteritis deaths occur in developing nations. Viruses are the main causative agent (~70%) of gastroenteritis episodes and their specific and early diagnosis via laboratory assays is very helpful for having successful antiviral therapy and reduction in infection burden. Regarding this importance, the present literature is the first review of updated improvements in the employing of different types of biosensors such as electrochemical, optical, and piezoelectric for sensitive, simple, cheap, rapid, and specific diagnosis of human gastroenteritis viruses. The Introduction section is a general discussion about the importance of viral gastroenteritis, types of viruses that cause gastroenteritis, and reasons for the combination of conventional diagnostic tests with biosensors for fast detection of viruses associated with gastroenteritis. Following the current laboratory detection tests for human gastroenteritis viruses and their limitations (with subsections: Electron Microscope (EM), Cell Culture, Immunoassay, and Molecular Techniques), structural features and significant aspects of various biosensing methods are discussed in the Biosensor section. In the next sections, basic information on viruses causing gastroenteritis and recent developments for fabrication and testing of different biosensors for each virus detection are covered, and the prospect of future developments in designing different biosensing platforms for gastroenteritis virus detection is discussed in the Conclusion and Future Directions section as well.

Molecular and epidemiological characterization of human adenoviruses infection among children with acute diarrhea in Shandong Province, China

Background

Human adenovirus (HAdV) had been recognized as one of the most common enteric viruses associated with acute diarrhea in children. The present study was carried out to demonstrate the molecular and epidemiological characterization of HAdV Infections among children in Shandong province in China between July 2017 and June 2018.

Methods

Fecal specimens were collected from children under 5 years old with acute diarrhea. DNA was extracted from the stool specimens and adenovirus DNA was detected by PCR amplification with specific primers. The amplification products were subjected to electrophoresis and visualized on a UV transilluminator. All positive RT-PCR amplification products were sequenced and the obtained sequences analyzed by MEGA (version 7.0). Demographic information and clinical manifestation data were also analyzed.

Results

In total, 656 fecal specimens were collected and the overall positive rate of HAdV was 7.47%. HAdV infections were detected in all age groups, in which children aged 13–24 months presented the highest positive rate. Seasonal pattern could be observed with a peak in December, January and February. Diarrhea, vomiting, dehydration and fever were the main clinical manifestations, in which vomiting was the most common accompanied symptom. By phylogenetic analysis, four species (A, B, C, and F) were detected and seven different serotypes were identified. HAdV-41 (48.98%, 24/49) was the most common serotype followed by HAdV-3 (18.37%, 9/49), HAdV-31 (14.29%, 7/49), HAdV-7 (8.16%, 4/49), HAdV-40 (4.08%, 2/49), HAdV-1 (4.08%, 2/49) and HAdV-2 (2.04%, 1/49).

Conclusion

This study indicated that HAdV infection was an important cause of acute diarrhea among children under 5 years old in Shandong province. The results will contribute to (a) increase understanding of the role of HAdV in diarrheal children and enhance identification of the predominant diarrhea pathogen for diagnosis; (b) avoid abuse of antibiotics; (c) monitor the change of prevalent HAdV serotypes and promote vaccine development and vaccination.

Murine norovirus virulence factor 1 (VF1) protein contributes to viral fitness during persistent infection

Murine norovirus (MNV) is widely used as a model for studying norovirus biology. While MNV isolates vary in their pathogenesis, infection of immunocompetent mice mostly results in persistent infection. The ability of a virus to establish a persistent infection is dependent on its ability to subvert or avoid the host immune response. Previously, we described the identification and characterization of virulence factor 1 (VF1) in MNV, and demonstrated its role as an innate immune antagonist. Here, we explore the role of VF1 during persistent MNV infection in an immunocompetent host. Using reverse genetics, we generated MNV-3 viruses carrying a single or a triple termination codon inserted in the VF1 ORF. VF1-deleted MNV-3 replicated to comparable levels to the wildtype virus in tissue culture. Comparative studies between MNV-3 and an acute MNV-1 strain show that MNV-3 VF1 exerts the same functions as MNV-1 VF1, but with reduced potency. C57BL/6 mice infected with VF1-deleted MNV-3 showed significantly reduced replication kinetics during the acute phase of the infection, but viral loads rapidly reached the levels seen in mice infected with wildtype virus after phenotypic restoration of VF1 expression. Infection with an MNV-3 mutant that had three termination codons inserted into VF1, in which reversion was suppressed, resulted in consistently lower replication throughout a 3 month persistent infection in mice, suggesting a role for VF1 in viral fitness in vivo. Our results indicate that VF1 expressed by a persistent strain of MNV also functions to antagonize the innate response to infection. We found that VF1 is not essential for viral persistence, but instead contributes to viral fitness in mice. These data fit with the hypothesis that noroviruses utilize multiple mechanisms to avoid and/or control the host response to infection and that VF1 is just one component of this.

Nonenteric Adenoviruses Associated with Gastroenteritis in Hospitalized Children

The object of this study was to investigate the frequency of human adenovirus (HAdV) infections in hospitalized pediatric patients. Stool samples were collected during a 1-year period (February 2018 to January 2019). HAdV was detected by a broad-range PCR and genotyped by sequencing and phylogenetic analysis. Demographic characteristics and detailed clinical information were analyzed for each patient. HAdV was detected in 7.1% of stool samples (34/476). Among these patients, 23.5% were coinfected with other enteric viral or bacterial pathogens. The majority (85.2%) of HAdV positives were detected in children of <5 years of age. Two HAdV species (B and C) with three types were identified in this study population. HAdV species F was not detected. Genetic analysis shows that the isolates circulating in our region present high diversity and do not exhibit clonal expansion. The presence of nonenteric HAdV in subjects with gastrointestinal symptoms and in immunocompromised patients has already been reported by different studies and underlines the need to develop routine molecular assays that have wide reactivity for most types of adenovirus in order to obtain an optimal tool for their rapid and accurate diagnosis. IMPORTANCE Gastroenteritis is the second leading cause of death among infants and children worldwide. Our study shows that adenovirus types other than 40 and 41 might be related to acute gastroenteritis. Therefore, a novel approach using diagnostic methods able to detect all adenovirus types is desirable in order to overcome the limitations of the current techniques.

An antiviral trap made of protein nanofibrils and iron oxyhydroxide nanoparticles

Minimizing the spread of viruses in the environment is the first defence line when fighting outbreaks and pandemics, but the current COVID-19 pandemic demonstrates how difficult this is on a global scale, particularly in a sustainable and environmentally friendly way. Here we introduce and develop a sustainable and biodegradable antiviral filtration membrane composed of amyloid nanofibrils made from food-grade milk proteins and iron oxyhydroxide nanoparticles synthesized in situ from iron salts by simple pH tuning. Thus, all the membrane components are made of environmentally friendly, non-toxic and widely available materials. The membrane has outstanding efficacy against a broad range of viruses, which include enveloped, non-enveloped, airborne and waterborne viruses, such as SARS-CoV-2, H1N1 (the influenza A virus strain responsible for the swine flu pandemic in 2009) and enterovirus 71 (a non-enveloped virus resistant to harsh conditions, such as highly acidic pH), which highlights a possible role in fighting the current and future viral outbreaks and pandemics.

Molecular and epidemiological characterization of human adenovirus and classic human astrovirus in children with acute diarrhea in Shanghai, 2017-2018

BACKGROUND

In addition to rotavirus and norovirus, human adenovirus (HAdV) and classic human astrovirus (classic HAstV) are important pathogens of acute diarrhea in infants and young children. Here, we present the molecular epidemiology of HAdV and classic HAstV in children with acute diarrhea in Shanghai.

METHODS

Fecal specimens were collected from 804 outpatient infants and young children diagnosed with acute diarrhea in Shanghai from January 2017 to December 2018. All of the samples were screened for the presence of HAdV and classic HAstV. HAdV and classic HAstV were detected using traditional PCR and reverse-transcription PCR, respectively. All of the HAdV and classic HAstV positive samples were genotyped by phylogenetic analysis.

RESULTS

Among the 804 fecal samples, 8.58% (69/804) of samples were infected with either HAdV or classic HAstV, and five were co-infected with two diarrhea viruses. The overall detection rates of HAdV and classic HAstV were 3.47% (28/804) and 5.22% (42/804), respectively. Four subgroups (A, B, C, and F) and seven genotypes (HAdV-C1, -C2, -B3, -C5, -A31, -F40, and -F41) of HAdV were detected. Subgroup F had the highest constituent ratio at 64.29% (18/28), followed by non-enteric HAdV of subgroup C (21.43%, 6/28) and subgroup B 10.71% (3/28). HAdV-F41 (60.71%, 17/28) was the dominant genotype, followed by HAdV-C2 (14.29%, 4/28) and HAdV-B3 (10.71%, 3/28). Two genotypes of classic HAstV (HAstV-1 and HAstV-5) were identified in 42 samples during the study period; HAstV-1 (95.24%, 40/42) was the predominant genotype, and the other two strains were genotyped as HAstV-5. No significant differences were found between boys and girls in the detection rates of HAdV (P = 0.604) and classic HAstV (P = 0.275). Over half of the HAdV infections (82.14%, 23/28) and classic HAstV infections (66.67%, 28/42) occurred in children less than 36 months. Seasonal preferences of HAdV and classic HAstV infections were summer and winter, respectively. In this study, the common clinical symptoms of children with acute diarrhea were diarrhea, vomiting, fever and abdominal pain.

CONCLUSIONS

Our findings indicate that HAdV and classic HAstV play important roles in the pathogenesis of acute diarrhea in children in Shanghai. Systematic and long-term surveillance of HAdV and classic HAstV are needed to monitor their prevalence in children and prevent major outbreak.

Rotavirus gastroenteritis in children hospitalized in northeastern Poland in 2006-2020: Severity, seasonal trends, and impact of immunization

OBJECTIVES

The introduction of the rotavirus vaccine in 2006 significantly reduced childhood incidence of acute gastroenteritis (AGE) worldwide. The rotavirus vaccine was included in Poland's national immunization program in 2021. Our study aimed to summarize the epidemiology of AGE in northeastern Poland prior to 2021 and to evaluate the effectiveness of voluntary, out-of-pocket rotavirus childhood vaccination on the incidence of rotavirus AGE.

METHODS

A review of patients aged 0-17 years with gastroenteritis hospitalized between 2006 and 2020 in northeastern Poland in the context of rotavirus vaccine coverage in the region.

RESULTS

Rotavirus was the most common agent of gastroenteritis in hospitalized patients. The seasonality of rotavirus gastroenteritis peaked between February and May in each year of study, except for 2020, when the COVID-19 pandemic skewed any viable comparison of seasonality. Rotavirus vaccine coverage in northeastern Poland did not exceed 25% during the study period and had no impact on hospitalization numbers.

CONCLUSIONS

Rotavirus was the primary causative agent of AGE in children hospitalized in northeastern Poland during the study period. Voluntary vaccinations did not affect the number of hospitalizations due to rotavirus AGE. Our data suggest that universal immunization is key to achieving a significant reduction of rotavirus-associated diarrhea.

Viral gastroenteritis in Tocantins, Brazil: characterizing the diversity of human adenovirus F through next-generation sequencing and bioinformatics

Human enteric adenovirus species F (HAdV-F) is one of the most common pathogens responsible for acute gastroenteritis worldwide. Brazil is a country with continental dimensions where continuous multiregional surveillance is vital to establish a more complete picture of the epidemiology of HAdV-F. The aim of the current study was to investigate the molecular epidemiology of HAdV-F using full-genome data in rural and low-income urban areas in northern Brazil. This will allow a genetic comparison between Brazilian and global HAdV-F strains. The frequency of HAdV-F infections in patients with gastroenteritis and molecular typing of positive samples within this period was also analysed. A total of 251 stool samples collected between 2010 and 2016 from patients with acute gastroenteritis were screened for HAdV-F using next-generation sequencing techniques. HAdV-F infection was detected in 57.8 % (145/251) of samples. A total of 137 positive samples belonged to HAdV-F41 and 7 to HAdV-F40. HAdV-F40/41 dual infection was found in one sample. Detection rates did not vary significantly according to the year. Single HAdV-F infections were detected in 21.9 % (55/251) of samples and mixed infections in 37.4 % (94/251), with RVA/HAdV-F being the most frequent association (21.5 %; 54/251). Genetic analysis indicated that the HAdV-F strains circulating in Brazil were closely related to worldwide strains, and the existence of some temporal order was not observed. This is the first large-scale HAdV-F study in Brazil in which whole-genome data and DNA sequence analyses were used to characterize HAdV-F strains. Expanding the viral genome database could improve overall genotyping success and assist the National Center for Biotechnology Information (NCBI)/GenBank in standardizing the HAdV genome records by providing a large set of annotated HAdV-F genomes.

Viral indicators for tracking domestic wastewater contamination in the aquatic environment

Waterborne enteric viruses are an emerging cause of disease outbreaks and represent a major threat to global public health. Enteric viruses may originate from human wastewater and can undergo rapid transport through aquatic environments with minimal decay. Surveillance and source apportionment of enteric viruses in environmental waters is therefore essential for accurate risk management. However, individual monitoring of the >100 enteric viral strains that have been identified as aquatic contaminants is unfeasible. Instead, viral indicators are often used for quantitative assessments of wastewater contamination, viral decay and transport in water. An ideal indicator for tracking wastewater contamination should be (i) easy to detect and quantify, (ii) source-specific, (iii) resistant to wastewater treatment processes, and (iv) persistent in the aquatic environment, with similar behaviour to viral pathogens. Here, we conducted a comprehensive review of 127 peer-reviewed publications, to critically evaluate the effectiveness of several viral indicators of wastewater pollution, including common enteric viruses (mastadenoviruses, polyomaviruses, and Aichi viruses), the pepper mild mottle virus (PMMoV), and gut-associated bacteriophages (Type II/III FRNA phages and phages infecting human Bacteroides species, including crAssphage). Our analysis suggests that overall, human mastadenoviruses have the greatest potential to indicate contamination by domestic wastewater due to their easy detection, culturability, and high prevalence in wastewater and in the polluted environment. Aichi virus, crAssphage and PMMoV are also widely detected in wastewater and in the environment, and may be used as molecular markers for human-derived contamination. We conclude that viral indicators are suitable for the long-term monitoring of viral contamination in freshwater and marine environments and that these should be implemented within monitoring programmes to provide a holistic assessment of microbiological water quality and wastewater-based epidemiology, improve current risk management strategies and protect global human health.

Study of the diagnostic value of interleukin-6 and interleukin-8 in children with acute gastroenteritis

Introduction

Gastroenteritis in children is responsible for high morbidity and mortality. Our aim was to determine the serum and fecal levels of interleukin-6 (IL-6) and interleukin-8 (IL-8) in children with acute gastroenteritis of viral and bacterial etiology to assess their utility as diagnostic biomarkers for these infections.

Methods

In this case-control study, the children were classified according to the pathogen recovered from the stool by bacterial culture or by direct viral antigen detection by enzyme immunoassay (EIA) into 50 children with acute bacterial gastroenteritis and 50 children with acute viral gastroenteritis. In addition, 50 apparently healthy children were included as a control group. Blood and stool samples were subjected to detection of IL-6 and IL-8.

Results

There were statistically significant elevations of total leucocytes counts, absolute neutrophils count, C-reactive protein, serum IL-6 and serum IL-8 in children with gastroenteritis compared to healthy children (p<0.001). CRP, serum IL-6 and IL-8 had significantly elevated levels in children with bacterial gastroenteritis compared to viral gastroenteritis. Fecal IL-6 and IL-8 had significantly elevated levels in children with acute gastroenteritis than in healthy control (p<0.001). The area under the curve (AUC) showed that CRP and serum IL-6 could be used as discriminative markers for acute bacterial gastroenteritis in children, in comparison to serum IL-8.

Conclusions

Elevated serum IL-6 and CRP can aid in differentiation between viral and bacterial gastroenteritis. Serum IL-8 had limited discrimination ability between viral and bacterial gastroenteritis. Stool levels of IL-6 and IL-8 were elevated in children with viral and bacterial gastroenteritis, however, their assessment by enzyme linked immunosorbent assay had technical limitations to be used as differentiation biomarkers.

Edible Dye-Enhanced Solar Disinfection with Safety Indication

The rural developing world faces disproportional inequity in drinking water access, where point-of-use water treatment technologies often fail to achieve adequate levels of pathogen removal, especially for viruses. Solar disinfection (SODIS) is practiced because of its universal applicability and low implementation cost, though the excessively long treatment time and lack of safety indication hinder wider implementation. This study presents an enhanced SODIS scheme that utilizes erythrosine-a common food dye-as a photosensitizer to produce singlet oxygen for virus inactivation and to indicate the completion of water disinfection through photobleaching color change. Experimental results and predictions based on global solar irradiance data suggest that over 99.99% inactivation could be achieved within 5 min in the majority of developing countries, reducing the time for SODIS by 2 orders of magnitude. Preserving the low cost of traditional SODIS, erythrosine embodies edible dye-enhanced SODIS, an efficient water disinfection method that could potentially be used by governments and non-governmental organizations to improve drinking water quality in rural developing communities.

A Multiplex PCR/LDR Assay for Viral Agents of Diarrhea with the Capacity to Genotype Rotavirus

Rotavirus and noroviruses are major causes of diarrhea. Variable rotavirus vaccination efficacy in Africa and Asia is multifactorial, including the diversity of circulating strains and viral co-infection. We describe a multiplexed assay that detects and genotypes viruses from stool specimens. It includes a one-step reverse transcriptase PCR reaction, a ligase detection reaction (LDR), then hybridization of fluorescent products to micro-beads. In clinical samples it detects rotavirus, caliciviruses (sapovirus and norovirus), mixed infections, and genotypes or genogroups of rotaviruses and noroviruses, respectively. The assay also has the capacity to detect hepatitis A. The assay was validated on reference isolates and 296 stool specimens from the US and Ghana. The assay was 97% sensitive and 100% specific. The genogroup was concordant in 100% of norovirus, and the genotype in 91% and 89% of rotavirus G- and P-types, respectively. Two rare rotavirus strains, G6P[6] and G6P[8], were detected in stool specimens from Ghana. The high-throughput assay is sensitive, specific, and may be of utility in the epidemiological surveillance for rare and emerging viral strains post-rotavirus vaccine implementation.

Accuracy of pediatric residents in determination of dehydration in children with gastroenteritis

Objective

The aim of the present study was to determine the accuracy of pediatric residents in diagnosis of dehydration in children with gastroenteritis.

Methods

This was a cross-sectional study in Dr. Sheikh Hospital, affiliated with Mashhad University of Medical Sciences (Mashhad, Iran), in 2016. One hundred fifteen children aged 1 month to 14 years with gastroenteritis were included according to easy sampling. All patients were weighed. Dehydration was scored as mild, moderate and severe by pediatric residents according to Nelson standard table including pulse rate, blood pressure, blood skin supplement, skin turgor, fontanel, mucus membrane, tear respiration and urine output criteria. Patients were rehydrated and reweighed consequently. Percent loss of body weight (PLBW) was calculated and compared with dehydration score. Statistical analysis was performed using SPSS windows program version 19 (SPSS Institute, Inc., Chicago, IL, USA).

Results

Of the115 children, 65 patients were male (56.5%) with the median age of 14.5 months. The Kendall's tau-b and Spearman correlation coefficient for residents' estimation and PLBW were 0.18 and 0.23 respectively (p=0.01 and 0.12 respectively). The ICC between estimated dehydration and PLBW was 0.47. According to residents' estimation and gold standard, PLBW was 6.76% and 1.33%, respectively. The serum level of sodium, potassium, urea and creatinine were 141.8 mEq/L, 4.6 mEq/L, 34.45 mg/dL and 0.6 mg/dL, respectively.

Conclusion

There is positive but weak correlation between residents' estimation and PLBW in patients with dehydration. It is necessary to enhance the educational level of pediatric residents to increase the accuracy of physical examination and decrease medical errors.

Comparison of two different combined test strips with fluorescent microspheres or colored microspheres as tracers for rotavirus and adenovirus detection

Background

Rotavirus (RV) and enteric adenovirus (AdV) mainly cause infantile infectious gastroenteritis. Several separate test methods for the detection of RV or AdV are currently available, but few tests are able to simultaneously detect both RV and AdV viruses, especially in primary medical institutions.

Methods

The present study was mainly designed to compare the performance of two combined test strips for the detection of RV and AdV: a rotavirus–adenovirus strip with fluorescent microspheres for tracers (FMT); and the CerTest rotavirus–adenovirus blister strip with colored microspheres for tracers (CMT). To test the strips cultures of RV, AdV and from other enteric pathogens were used, in addition to 350 stool specimens from 45 symptomatic patients with gastrointestinal infections.

Results

Detection thresholds for RV and AdV cultures using serial dilutions showed that the sensitivity of FMT was significantly higher than that of CMT (both P < 0.05). Specificity evaluation demonstrated that with culture mixtures of Coxsackie (A16), ECHO (type30), and entero- (EV71) viruses there was no detection of cross reaction using the two test strips, i.e., all the results were negative. With regard to the detection of RV in 350 clinical specimens, the total coincidence rate was 92.9%, the positive coincidence rate was 98.2%, and the negative coincidence rate was 90.8%. With regard to AdV detection, the total coincidence rate was 95.4%, the positive coincidence rate was 95.2%, and the negative coincidence rate was 95.5%.

Conclusions

FMT performed better than CMT with regard to the combined detection of RV and AdV.

Evolution in fecal bacterial/viral composition in infants of two central African countries (Gabon and Republic of the Congo) during their first month of life

Few studies have analyzed the gut microbiota of child in unindustrialized countries, but none during the first month of life. Stool samples were collected from healthy newborns in hospitals of Gabon (n = 6) and Republic of the Congo (n = 9) at different time points during the first month of life: meconium, day 2 (D02), day 7 (D07) and day 28 (D28). In addition, one fecal sample was collected from each mother after delivery. Metagenomic sequencing was performed to determine the bacterial communities, and multiplex real-time PCR was used to detect the presence of seven enteric viruses (rotavirus a, adenovirus, norovirus I and II, sapovirus, astrovirus, enterovirus) in these samples. Bacterial diversity was high in the first days of life, and was dominated by the genus Prevotella. Then, it rapidly decreased and remained low up to D28 when the gut flora was composed almost exclusively of strictly anaerobic bacteria. Each infant’s fecal bacterial microbiota composition was significantly closer to that of their mother than to that of any other woman in the mothers’ group, suggesting an intrauterine, placental or amniotic fluid origin of such bacteria. Moreover, bacterial communities differed according to the delivery mode. Overall, the bacterial microbiota communities displayed a similar diversification and expansion in newborns within and between countries during the first four weeks of life. Moreover, six of the fifteen infants of this study harbored enteric viruses (rotavirus, enterovirus and adenovirus) in fecal samples, but never in the meconium. A maternal source for the viruses detected at D02 and D07 can be excluded because none of them was found also in the child’s mother. These findings improve our knowledge on the gut bacterial and viral communities of infants from two Sub-Saharan countries during their first month of life.

Assessment and Evaluation of an Integrated Hybrid Anaerobic-Aerobic Sewage Treatment System for the Removal of Enteric Viruses

The capability of a cost-effective and a small size decentralized pilot wastewater treatment plant (WWTP) to remove enteric viruses such as rotavirus, norovirus genogroup I (GGI), norovirus genogroup II (GGII), Hepatitis E virus (HEV), and adenovirus was studied. This pilot plant is an integrated hybrid anaerobic/aerobic setup which consisted of anaerobic sludge blanket (UASB), biological aerated filter (BAF), and inclined plate settler (IPS). Both the UASB and BAF are packed with a non-woven polyester fabric (NWPF). Results indicated that the overall log₁₀ reductions of enteric viruses' genome copies through the whole system were 3.1 ± 1, 3.3 ± 0.5, and 2.6 ± 0.9 log₁₀ for rotavirus, norovirus GGI, and adenovirus, respectively. Reduction efficiency for both norovirus GGII and HEV after the different treatment steps could not be calculated because there were no significant numbers of positive samples for both viruses. The overall reduction of rotavirus infectious units through the whole system was 2.2 ± 0.8 log₁₀ reduction which is very close to the overall log₁₀ reduction of adenovirus infectious units through the whole system which was 2.1 ± 0.8 log₁₀ reduction. There was no considerable difference in the removal efficiency for different rotavirus G and P types. Adenovirus 41 was the only type detected in the all positive samples. Although the pilot WWTP investigated is cost effective, has a small footprint, does not need a long distance network pipes, and easy to operate, its efficiency to remove enteric viruses is comparable with the conventional centralized WWTPs.

FRNA Bacteriophages as Viral Indicators of Faecal Contamination in Mexican Tropical Aquatic Systems

A particular challenge to water safety in populous intertropical regions is the lack of reliable faecal indicators to detect microbiological contamination of water, while the numerical relationships of specific viral indicators remain largely unexplored. The aim of this study was to investigate the numerical relationships of FRNA-bacteriophage genotypes, adenovirus 41, and human adenoviruses (HADV) in Mexican surface water systems to assess sewage contamination. We studied the presence of HADV, HADV41 and FRNA bacteriophage genotypes in water samples and quantified by qPCR and RT-qPCR. Virus and water quality indicator variances, as analyzed by principal component analysis and partial least squared regression, followed along the major percentiles of water faecal enterococci. FRNA bacteriophages adequately deciphered viral and point source water contamination. The strongest correlation for HADV was with FRNA bacteriophage type II, in water samples higher than the 50^th percentiles of faecal enterococci, thus indicating urban pollution. FRNA bacteriophage genotypes I and III virus indicator performances were assisted by their associations with electrical conductivity and faecal enterococci. In combination, our methods are useful for inferring water quality degradation caused by sewage contamination. The methods used have potential for determining source contamination in water and, specifically, the presence of enteric viruses where clean and contaminated water have mixed.

SAPOVIRUSES IN CHILDREN WITH ACUTE GASTROENTERITIS FROM MANAUS , AMAZON REGION, BRAZIL, 2010-2011

Sapoviruses (SaVs) are responsible for acute gastroenteritis in humans, especially children and the elderly. In Brazil, data on SaVs infections are very limited, especially in Northern Brazil. Here, we investigated the occurrence of SaVs in samples from hospitalized children under ten years old that presented acute gastroenteritis. Positive samples were genotyped and phylogenetic analysis was performed using prototype strains sequences obtained from GenBank database. In total, 156 fecal samples were screened by RT-PCR for SaVs. A positivity rate of 3.8% (6/156) was found in children under three years of age. Four genotypes were detected: GI.I, GI.2 and GII.2?-GII.4?/GII.4, suggesting a possible inter-genotypes recombination. Most infections (83.3%) occurred between August and September. The positivity was similar to that found in other countries and genotyping demonstrated the presence of distinct genotypes. To our knowledge, this is the first study reporting the circulation of SaVs in Manaus, state of Amazonas, Amazon region, Brazil.

The impact of rotavirus vaccination on emergency department visits and hospital admissions for acute diarrhea in children under 5 years

Summary Introduction: Acute diarrheal disease is the second cause of death in children under 5 years. In Brazil, from 2003 to 2009, acute diarrhea was responsible for nearly 100,000 hospital admissions per year and 4% of the deaths in children under 5 years. Rotavirus is the leading cause of severe acute diarrhea worldwide. In 2006, the rotavirus monovalent vaccine (RV1) was added to the Brazilian National Immunization Program. Objectives: To analyze the impact of the RV1 on emergency department (ED) visits and hospital admissions for acute diarrhea. Method: A retrospective ecologic study at the University Hospital, University of São Paulo. The study analyzed the pre-vaccine (2003–2005) and the post-vaccine (2007–2009) periods. We screened the main diagnosis of all ED attendances and hospital admissions of children under 5 years in an electronic registry system database and calculated the rates of ED visits and hospital admissions. The reduction rate was analyzed according to the following formula: reduction (%) = (1 - odds ratio) x 100. Results: The rates of ED visits for acute diarrhea was 85.8 and 80.9 per 1,000 total ED visits in the pre and post vaccination periods, respectively, resulting in 6% reduction (95CI 4 to 9%, p<0.001). The rates of hospital admissions for acute diarrhea was 40.8 per 1,000 in the pre-vaccine period and dropped to 24.9 per 1,000 hospitalizations, resulting in 40% reduction (95CI 22 to 54%, p<0.001). Conclusion: The introduction of the RV1 vaccine resulted in 6% reduction in the ED visits and 40% reduction in hospital admissions for acute diarrhea.

Norovirus Gastroenteritis in a Birth Cohort in Southern India

BACKGROUND

Noroviruses are an important cause of gastroenteritis but little is known about disease and re-infection rates in community settings in Asia.

METHODS

Disease, re-infection rates, strain prevalence and genetic susceptibility to noroviruses were investigated in a birth cohort of 373 Indian children followed up for three years. Stool samples from 1856 diarrheal episodes and 147 vomiting only episodes were screened for norovirus by RT-PCR. Norovirus positivity was correlated with clinical data, secretor status and ABO blood group.

RESULTS

Of 1856 diarrheal episodes, 207 (11.2%) were associated with norovirus, of which 49(2.6%) were norovirus GI, 150(8.1%) norovirus GII, and 8 (0.4%) were mixed infections with both norovirus GI and GII. Of the 147 vomiting only episodes, 30 (20.4%) were positive for norovirus in stool, of which 7 (4.8%) were norovirus GI and 23 (15.6%) GII. At least a third of the children developed norovirus associated diarrhea, with the first episode at a median age of 5 and 8 months for norovirus GI and GII, respectively. Norovirus GI.3 and GII.4 were the predominant genotypes (40.3% and 53.0%) with strain diversity and change in the predominant sub-cluster over time observed among GII viruses. A second episode of norovirus gastroenteritis was documented in 44/174 (25.3%) ever-infected children. Children with the G428A homozygous mutation for inactivation of the FUT2 enzyme (se428se428) were at a significantly lower risk (48/190) of infection with norovirus (p = 0.01).

CONCLUSIONS

This is the first report of norovirus documenting disease, re-infection and genetic susceptibility in an Asian birth cohort. The high incidence and apparent lack of genogroupII specific immunity indicate the need for careful studies on further characterization of strains, asymptomatic infection and shedding and immune response to further our understanding of norovirus infection and disease.

Post-exposure antiviral treatment of norovirus infections effectively protects against diarrhea and reduces virus shedding in the stool in a mortality mouse model

Noroviruses are a leading cause of gastroenteritis across the world in all age groups and are linked to increased hospitalization and mortality in children, the elderly and immunocompromised. The development of specific antiviral treatment for norovirus gastroenteritis is urgently needed. We explored in a mouse model whether an inhibitor of norovirus replication could be used therapeutically post murine norovirus (MNV)-infection of mice. Using the MNV, we previously discovered that the viral polymerase inhibitor 2'-C-methylcytidine (2CMC) is able to protect against diarrhea and mortality in mice when used prophylactically and to block the transmission of MNV between mice. Here, we investigated whether 2CMC could be used therapeutically, starting treatment between 12 h and 3 days post-infection with 2CMC. Post-exposure treatment of MNV-infected mice with 2CMC was efficient up to 2 days after infection, preventing norovirus-induced diarrhea, delaying and reducing MNV shedding in stool of treated mice. Rehydration of 2CMC-treated animals did not result in a further improvement of the disease evolution compared to antiviral treatment only. The presence of MNV antigens and inflammation in the small intestine of infected mice inversely correlated with the effectiveness of delayed antiviral treatment. Anti-MNV IgGs were detected in re-challenged mice 10 weeks after the first contact, these protected the mice from re-infection. We here demonstrate the benefit of antiviral treatment in ongoing norovirus infections.

Prevalence and molecular characterization of human noroviruses and sapoviruses in Ethiopia

Viral gastroenteritis is a major public health problem worldwide. In Ethiopia, very limited studies have been done on the epidemiology of enteropathogenic viruses. The aim of this study was to detect and characterize noroviruses (NoVs) and sapoviruses (SaVs) from acute gastroenteritis patients of all ages. Fecal samples were collected from diarrheic patients (n = 213) in five different health centers in Addis Ababa during June-September 2013. The samples were screened for caliciviruses by reverse transcription polymerase chain reaction (RT-PCR) using universal and genogroup-specific primer pairs. Phylogenetic analyses were conducted using the sequences of the PCR products. Of the clinical samples, 25.3 % and 4.2 % were positive for NoV and SaV RNA, respectively. Among the norovirus positives, 22 were sequenced further, and diverse norovirus strains were identified: GI (n = 4), GII (n = 17) and GIV (n = 1). Most strains were GII (n = 17/22: 77.2 %), which were further divided into three different genotypes (GII.4, GII.12/GII.g recombinant-like and GII.17), with GII.17 being the dominant (7/17) strain detected. GI noroviruses, in particular GI.4 (n = 1), GI.5 (n = 2) and GI.8 (n = 1), were also detected and characterized. The GIV strain detected is the first from East Africa. The sapoviruses sequenced were also the first reported from Ethiopia. Collectively, this study showed the high burden and diversity of noroviruses and circulation of sapoviruses in diarrheic patients in Ethiopia. Continued surveillance to assess their association with diarrhea is needed to define their epidemiology, disease burden, and impact on public health.

A disposable chemical heater and dry enzyme preparation for lysis and extraction of DNA and RNA from microorganisms

Sample preparation, including bacterial lysis, remains a hurdle in the realization of complete point-of-care tests for many pathogens. Here, we developed a sample preparation methodology for enzymatic lysis and sample heating for low-resource, point-of-care applications. We show an instrument-free chemical heater system for rapid lysis of a gram-positive bacterium (Staphylococcus aureus) and an RNA virus (human respiratory syncytial virus) using a dried lysis enzyme mixture (achromopeptidase) for S. aureus. After a lysis step (<1 minute), lysis enzymes are heat deactivated (<5 minutes) using a simple disposable chemical heater. We demonstrated that both DNA and RNA in the heat-treated sample could be directly amplified without purification, even in the presence of a clinically-obtained human nasal sample. This simple approach to dry enzyme storage and sample heating is adaptable to many applications where samples need to be lysed, including use in low-resource laboratories and in single-use or cartridge-based point-of-care diagnostic devices.

Prevalence of adenovirus and rotavirus infection in immunocompromised patients with acute gastroenteritis in Portugal

AIM: To characterize the prevalence of rotavirus (RV) and adenovirus (AdV) infections in immunocompromised patients with acute gastroenteritis.

METHODS: The presence of RV and AdV (serotypes 40 and 41) was evaluated in 509 stool samples obtained between January 2009 and December 2010 from 200 immunocompromised patients (83 females and 117 males; median age 21 years old, range 0-72. The diagnosis of infection was performed as a routine procedure and the presence of RV and AdV (serotypes 40 and 41) was determined by immunochromatography using the RIDA^® Quick Rota-Adeno-Kombi kit (r-Biopharm, Darmstadt, Germany). The data analysis and description of seasonal frequencies were performed using computer software IBM^® SPSS^® (Statistical Package for Social Sciences) Statistics version 20.0 for Mac. The frequencies of infection were compared into different age and gender groups by χ² test.

RESULTS: The study revealed 12.4% AdV positive samples and 0.8% RV positive samples, which correspond to a prevalence of 6.5% and 1.5%, respectively. AdV was more frequent between October 2009 and April 2010, while RV was identified in April 2010 and July 2010. The stool analysis revealed that from the 509 samples, 63 (12.4%) were positive for AdV and 4 (0.8%) positive for RV, which by resuming the information of each patient, lead to an overall prevalence of AdV and RV of 6.5% (13/200 patients) and 1.5% (3/200 patients), respectively. The stratification of the analysis regarding age groups showed a tendency to an increased prevalence of infection in paediatric patients between 0-10 years old. Considering the seasonal distribution of these infections, our study revealed that AdV infection was more frequent between October 2009 and April 2010, while RV infection was characterized by two distinct peaks (April 2010 and July 2010).

CONCLUSION: The overall prevalence of AdV and RV infection in immunocompromised patients with acute gastroenteritis was 8% and AdV was the most prevalent agent.

Detection of Dientamoeba fragilis in Portuguese children with acute gastroenteritis between 2011 and 2013

Dientamoeba fragilis is an inhabitant of human gastrointestinal tract with a worldwide distribution. The first description considered this protozoan a rare and harmless commensal, since then it has struggled to gain recognition as a pathogen. Commercial multiplex real-time PCR was used to detect D. fragilis in fecal samples from hospitalized children (⩽18 years) with acute gastrointestinal disease, admitted to two hospitals of Lisbon area, with different demographic characteristics. A total of 176 children were studied, 103 (58·5%) male, 144 (81·8%) children between 0 and 5 years and 32 (18·2%) above 6 years old. The overall protozoa frequency considering the four tested microorganisms were 8·5% (15/176), and the most frequently found protozoan was D. fragilis, 6·3% (11/176). Dientamoeba fragilis frequency was higher among older children (21·9%), than younger children (2·8%), and greater in boys (6·8%) than in girls (5·5%). All positive children presented with diarrhoea associated with vomiting, fever and abdominal pain. Infection was associated with the age of children (P < 0·001), school attendance (P = 0·002) and consumption of certain foods (P = 0·014), e.g. cakes with crème and ham. The frequency of diantamoebiasis found in a cohort of hospitalized Portuguese children, with acute gastrointestinal disease, could be considered a very high value when compared with the protozoan frequency normally associated with this pathology.

Detection of rotavirus and other enteropathogens in children hospitalized with acute gastroenteritis in Havana, Cuba

The aim of the study was to diagnose infections with rotavirus and other enteric pathogens in children under five years old with acute gastroenteritis and to identify the most common epidemiological and clinical characteristics of these pathogens. The study was conducted using 110 stool samples from the same number of children under five years old who were inpatients at three paediatric hospitals in Havana, Cuba, between October and December 2011. The samples were tested for rotavirus and other enteric pathogens using traditional and molecular microbiological methods. Pathogens were detected in 85 (77.3 %) of the children. Rotavirus was the most commonly found, appearing in 54.5 % of the children, followed by bacteria (29 %) and parasites (10.9 %). Other viral pathogens detected included adenovirus (6.4 %) and astrovirus (3.6 %). In rotavirus-positives cases, at least one other pathogen was detected, usually a bacterium (26.6 %). More than three episodes of watery diarrhea in 24 hours were observed in 78.3 % of the cases. Dehydration was found in 30 (50 %) rotavirus-positive children, of whom seven (11.6 %) were transferred to an intensive care unit due to complications of metabolic acidosis. Rotavirus was most commonly observed among children under 12 months old (65 %). The highest incidence of infection occurred in children who were under the care of a relative at home (78.3 %), had not been breastfed (65 %), or had been breastfed for less than six months (28.3 %). The genotype combinations most frequently found were G9P8 (28.3 %) and G1P8 (10 %). This study demonstrates the presence of rotavirus and other enteric pathogens as causes of gastroenteritis in hospitalized infants and young children in Cuba.

Prevalence of Rotaviruses Groups A and C in Egyptian Children and Aquatic Environment

The objective of this study is to compare the prevalence of rotaviruses groups A and C in Egyptian children and aquatic environment. From 110 stool specimens of children with acute diarrhea and using RT-PCR, 35 samples (31.8 %) were positive for human rotavirus group A and 15 samples (13.6 %) were positive for human rotavirus group C. From 96 samples collected from Zenin wastewater treatment plant over a 2-year period (November 2009-October 2011) and using RT-PCR, rotavirus group A was detected in (4/24) 16.7 %, (5/24) 20.8 %, (4/24) 16.7 %, and (4/24) 16.7 %, while rotavirus group C was detected in (2/24) 8.3 %, (3/24) 12.5 %, (3/24) 12.5 %, and (0/24) 0 % in raw sewage, after primary sedimentation, after secondary sedimentation, and after final chlorination, respectively. Moreover, from 96 samples collected from El-Giza water treatment plant over a 2-year period (November 2009-October 2011), rotavirus group A was detected in (7/24) 29.2 %, (6/24) 25 %, (5/24) 20.8 %, and (3/24) 12.5 %, while rotavirus group C was detected in (3/24) 12.5 %, (1/24) 4.2 %, (1/24) 4.2 %, and (0/24) 0 % in raw Nile water, after sedimentation, after sand filtration, and after final chlorination, respectively. Using SYBR Green real-time RT-PCR, the number of human rotavirus group A genome or infectious units was higher than rotavirus group C. VP6 sequence analysis of the RT-PCR positive rotavirus group C samples revealed that four clinical specimens and three environmental samples showed similar sequences clustered with Moduganari/Human Nigerian strain AF 325806 with 98 % homology, and two clinical specimens and one environmental sample showed similar sequences clustered with Dhaka CB/Human Bangladesh strain AY 754826 with 97 % homology.

Evaluation of the safety and adverse effects of goreisan/wulingsan, a traditional Japanese-chinese herbal formulation (kampo), in a rat model: a toxicological evaluation

Diarrhea is the second leading cause of death among children less than 5 years of age. Most of these deaths occur in developing countries in the tropical areas of Africa and South Asia. Goreisan/Wulingsan, a formula of Japanese-Chinese medicinal herbs (Kampo), has been used for the treatment of diarrhea and vomiting from ancient times in East Asia. Therefore, we planned a randomized controlled clinical trial of Goreisan/Wulingsan in Bangladeshi children. Although it is believed to be safe in East Asia, information regarding its toxicity on animals is scarce. Since Goreisan/Wulingsan has never been used in Bangladesh, it was necessary to ensure the safety of the formula in an animal experiment. Rats were assigned to a control group (normal saline, n = 4) or various Goreisan/Wulingsan groups (n = 26) receiving doses of 1 to 8 mg/g/day (7.7 to 61.5 times the recommended pediatric dose) over a period of 25 days. Their activities and health conditions were observed until they were sacrificed, after which blood samples were collected for biochemical liver function tests. The kidneys, liver and heart tissue were collected for histopathological study. No lethality was observed during the experiment. All of the rats consumed the doses completely and no constipation was observed, suggesting the absence of any inhibitory effect on intestinal motion. Also, no abnormal neurological activity was detected, nor any significant elevation of AST, ALT or ALP levels, except for AST and ALT at the highest dose of 8 mg/g/day. Histopathological studies of the kidneys, liver and heart tissues revealed no abnormalities. In conclusion, our results showed that Goreisan/Wulingsan is safe for rats, thereby justifying the use of the drug in a human trial.

Acute gastroenteritis and enteric viruses in hospitalised children in southern Brazil: aetiology, seasonality and clinical outcomes

Viral acute gastroenteritis (AG) is a significant cause of hospitalisation in children younger than five years. Group A rotavirus (RVA) is responsible for 30% of these cases. Following the introduction of RVA immunisation in Brazil in 2006, a decreased circulation of this virus has been observed. However, AG remains an important cause of hospitalisation of paediatric patients and only limited data are available regarding the role of other enteric viruses in these cases. We conducted a prospective study of paediatric patients hospitalised for AG. Stool samples were collected to investigate human adenovirus (HAdV), RVA, norovirus (NoV) and astrovirus (AstV). NoV typing was performed by nucleotide sequencing and phylogenetic analysis. From the 225 samples tested, 60 (26%) were positive for at least one viral agent. HAdV, NoV, RVA and AstV were detected in 16%, 8%, 6% and 0% of the samples, respectively. Mixed infections were found in nine patients: HAdV/RVA (5), HAdV/NoV (3) and HAdV/NoV/RVA (1). The frequency of fever and lymphocytosis was significantly higher in virus-infected patients. Phylogenetic analysis of NoV indicated that all of these viruses belonged to genotype GII.4. The significant frequency of these pathogens in patients with AG highlights the need to routinely implement laboratory investigations.

The significance of serum and fecal levels of interleukin-6 and interleukin-8 in hospitalized children with acute rotavirus and norovirus gastroenteritis

BACKGROUND

Rotavirus and norovirus are the most common known causes of viral gastroenteritis in children. This study examined the association between serum interleukin 6 (IL-6) and interleukin 8 (IL-8) levels and disease severity in the acute phase of rotavirus and norovirus gastroenteritis in children, and it also explored the role of fecal cytokine levels in children with viral and bacterial gastroenteritis.

METHODS

This prospective study enrolled patients aged 4 months to 14 years admitted with acute gastroenteritis in a tertiary care center. Peripheral blood samples were collected for IL-6 and IL-8 assays within the first 3 days of diarrhea. Stool samples were obtained from the patients in the first 24 hours after admission.

RESULTS

Serum IL-6 and IL-8 were measured in children with viral (n = 66) and bacterial (n = 23) infections, and in healthy controls (n = 10). In the acute phase of gastroenteritis, a moderately positive correlation was found between serum IL-6 levels and disease severity (rs = 0.41, p < 0.01). Serum IL-8 levels correlated with the duration of fever (rs = 0.28, p = 0.03). Fecal IL-6 levels correlated with the maximum number of daily bowel movements (rs = 0.35, p < 0.05). Rotavirus infection induced significantly higher serum IL-8 levels than norovirus infection (p < 0.05). Receiver operating characteristic (ROC) curve analysis showed that absolute neutrophil count (ANC), maximum body temperature (BT), and Vesikari score were significant predictors in discriminating rotavirus from norovirus gastroenteritis.

CONCLUSION

IL-6 and IL-8 are involved in the pathogenesis of acute gastroenteritis in both rotavirus and norovirus. An ANC of less than 9000/mm(3), maximum BT of less than 38.2°C, and Vesikari score of less than 14 at the end of the course are potential predictors of norovirus infection in children compared with rotavirus gastroenteritis.

Genetic diversity and distribution of human norovirus in China (1999-2011)

Noroviruses (NoVs) are a leading cause of epidemic and sporadic acute gastroenteritis worldwide. However, the genetic diversity and geographical distribution of NoV isolates from China have not been well described thus far. In this study, all NoV sequences obtained in China from 1999 to 2011 (n = 983), both partial and complete genomes, were downloaded from GenBank. Genotyping and phylogenetic and recombination analyses were performed in order to gain a better understanding of the distribution and genetic diversity of NoVs in China. The results indicated that approximately 90% of NoV sequences were obtained from the coastal regions of China, and most of the NoV sequences from distinct geographical regions appeared to be closely related. GII.4 was the most prevalent genotype, accounting for 64.4% of all genotypes, followed by GII.12 (13.9%) and GII.3 (7.0%). Over the last decade, the GII.4 variants were dominated by successive circulation of GII.4/2002, GII.4/2004, GII.4/2006b, and GII.4/2008, with GII.4/2006b continuing to date. A relatively high frequency of NoV intergenotype recombinants was identified. The most common ORF1/ORF2 intergenotype recombinant was GII.12/GII.4 (n = 11), and the relative frequency was up to 30% among all the recombinant strains (n = 36). These findings may aid in the evaluation and implementation of appropriate measures for monitoring NoV infectious diseases in China.

Enteric pathogens in stored drinking water and on caregiver's hands in Tanzanian households with and without reported cases of child diarrhea

BACKGROUND

Diarrhea is one of the leading causes of mortality in young children. Diarrheal pathogens are transmitted via the fecal-oral route, and for children the majority of this transmission is thought to occur within the home. However, very few studies have documented enteric pathogens within households of low-income countries.

METHODS AND FINDINGS

The presence of molecular markers for three enteric viruses (enterovirus, adenovirus, and rotavirus), seven Escherichia coli virulence genes (ECVG), and human-specific Bacteroidales was assessed in hand rinses and household stored drinking water in Bagamoyo, Tanzania. Using a matched case-control study design, we examined the relationship between contamination of hands and water with these markers and child diarrhea. We found that the presence of ECVG in household stored water was associated with a significant decrease in the odds of a child within the home having diarrhea (OR = 0.51; 95% confidence interval 0.27-0.93). We also evaluated water management and hygiene behaviors. Recent hand contact with water or food was positively associated with detection of enteric pathogen markers on hands, as was relatively lower volumes of water reportedly used for daily hand washing. Enteropathogen markers in stored drinking water were more likely found among households in which the markers were also detected on hands, as well as in households with unimproved water supply and sanitation infrastructure.

CONCLUSIONS

The prevalence of enteric pathogen genes and the human-specific Bacteroidales fecal marker in stored water and on hands suggests extensive environmental contamination within homes both with and without reported child diarrhea. Better stored water quality among households with diarrhea indicates caregivers with sick children may be more likely to ensure safe drinking water in the home. Interventions to increase the quantity of water available for hand washing, and to improve food hygiene, may reduce exposure to enteric pathogens in the domestic environment.

Epidemiology of human noroviruses and updates on vaccine development

PURPOSE OF REVIEW

Noroviruses (NoVs) are the most common cause of epidemic and sporadic cases of acute gastroenteritis worldwide. This review summarizes recent NoV disease burden estimates, epidemiology findings and provides an update on virus-like particle (VLP) vaccine studies.

RECENT FINDINGS

NoVs are the leading cause of food-borne gastroenteritis and are replacing rotavirus as the predominant gastrointestinal pathogen in pediatric populations. Genogroup II, genotype 4 NoVs (GII.4) remain the dominant genotype worldwide. Increased NoV activity reported in late 2012 was associated with the emergence of a new GII.4 variant called Sydney 2012. New studies suggest that human NoVs can bind a larger range of histoblood group antigens, a susceptibility factor for NoV illness, thus expanding the susceptible population pool for infection. Intranasal immunization with a monovalent GI NoV VLP vaccine showed proof-of-concept efficacy. Studies using intramuscular immunization with a bivalent formulation including GII.4 VLPs are now underway.

SUMMARY

The importance of NoVs as a major gastrointestinal pathogen underscores the need for well tolerated and effective vaccines. Results of VLP vaccine trials appear promising. However, the rapid evolution of NoV genotypes through antigenic drift and changing glycan specificities provide new challenges to epidemiology studies and vaccine trials.

Detection and characterisation of rotaviruses from children less than 5 years hospitalised with acute gastroenteritis in Nagercoil

Group A rotavirus continues to be the major cause of severe gastroenteritis in young children in developing countries. In this study, we report the prevalence and genotype of rotaviruses identified from children <5 years of age hospitalised with acute gastroenteritis from Nagercoil, Tamil Nadu from 2007-2010. From the 139 children included in the study, 71 samples (51%) were positive by ELISA and 65 samples were positive by PCR-based methods. G1P[8] (44.6%) was the most commonly identified genotype. In addition, we report detection of rotavirus in two of three CSF samples from children with seizures.

Characterising the aetiology of severe acute gastroenteritis among patients visiting a hospital in Qatar using real-time polymerase chain reaction

Background

Acute gastroenteritis (AGE) remains a common cause of clinic visits and hospitalizations, though its aetiology has not been determined in Qatar.

Methods

We performed a prospective, emergency department–based study of 288 children and adults with AGE. Stool specimens were collected at presentation from June to November 2009. Faecal specimens were tested, using real-time PCR, for a panel of four viral (norovirus, adenovirus, astrovirus and rotavirus) and bacterial pathogens.

Results

Viral and bacterial pathogens were detected in 131 (45.5%) and 34 (12.2%) of the 288 patients recruited. The most commonly detected pathogens were norovirus (28.5%), rotavirus (10.4%), followed by adenovirus (6.25%) and astrovirus (0.30%). Norovirus was the most commonly detected viral pathogen amongst all the age groups with an almost even distribution in all age groups. Rotavirus and adenovirus were more common in children under 5 yr of age. Astrovirus was found in only one person.

Conclusions

Viruses, especially noroviruses, are associated with severe diarrhoea in children and adults in Qatar. Further studies to confirm the findings and to explore the causes of illness among patients from whom a pathogen cannot be determined are needed.

Prevalence of 10 human polyomaviruses in fecal samples from children with acute gastroenteritis: a case-control study

We conducted a case-control study to explore the prevalence of 10 human polyomaviruses in fecal specimens from hospitalized children with diarrhea and asymptomatic control subjects by using multiplex PCR detected by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The differences between cases and controls were not statistically significant.

Lack of nonspecific protection against all-cause nonrotavirus gastroenteritis by vaccination with orally administered rotavirus vaccine

OBJECTIVES

Acute gastroenteritis (AGE) is recognized as a global, common threat to child survival, especially in developing countries. Rotavirus, in particular, has been implicated as a leading cause of severe AGE; however, there are numerous other pathogens that also cause AGE. Several studies have demonstrated that oral vaccination against rotavirus has generated the unanticipated benefit of protecting against AGE caused by nonrotavirus pathogens.

METHODS

Safety and efficacy of the pentavalent bovine-human reassortant rotavirus vaccine were studied in multiple populations, including children of the Navajo and White Mountain Apache tribes in the southwestern United States. Stool specimens were collected from children with AGE and tested for rotavirus using an enzyme immunoassay. Analyses were conducted to detect the presence or absence of a vaccine effect on incidence, severity, and duration of AGE in which rotavirus was not detected.

RESULTS

The majority of AGE (N = 558: 472 nonrotavirus vs 86 rotavirus) occurred between August 2002 and March 2004 among children ranging from ages 4 to 23 months. The incidence of nonrotavirus AGE was similar by vaccine groups with an incidence rate ratio of 1.07 (incidence rate ratio = vaccinated/unvaccinated, 95% confidence interval 0.89-1.29). The hazards of first, second, third, or any AGE in which rotavirus was not detected differed little by vaccination status (P > 0.05). Duration of symptoms and severity of nonrotavirus AGE were similar by vaccine group.

CONCLUSIONS

There was no vaccine effect on frequency or severity of nonrotavirus AGE.

Sweep flocculation and adsorption of viruses on aluminum flocs during electrochemical treatment prior to surface water microfiltration

Bench-scale experiments were performed to evaluate virus control by an integrated electrochemical-microfiltration (MF) process from turbid (15 NTU) surface water containing moderate amounts of dissolved organic carbon (DOC, 5 mg C/L) and calcium hardness (50 mg/L as CaCO3). Higher reductions in MS2 bacteriophage concentrations were obtained by aluminum electrocoagulation and electroflotation compared with conventional aluminum sulfate coagulation. This was attributed to electrophoretic migration of viruses, which increased their concentrations in the microenvironment of the sacrificial anode where coagulant precursors are dissolved leading to better destabilization during electrolysis. In all cases, viruses were not inactivated implying measured reductions were solely due to their removal. Sweep flocculation was the primary virus destabilization mechanism. Direct evidence for virus enmeshment in flocs was provided by two independent methods: quantitative elution using beef extract at elevated pH and quantitating fluorescence from labeled viruses. Atomic force microscopy studies revealed a monotonically increasing adhesion force between viruses immobilized on AFM tips and floc surfaces with electrocoagulant dosage, which suggests secondary contributions to virus uptake on flocs from adsorption. Virus sorption mechanisms include charge neutralization and hydrophobic interactions with natural organic matter removed during coagulation. This also provided the basis for interpreting additional removal of viruses by the thick cake formed on the surface of the microfilter following electrocoagulation. Enhancements in virus removal as progressively more aluminum was electrolyzed therefore embodies contributions from (i) better encapsulation onto greater amounts of fresh Al(OH)3 precipitates, (ii) increased adsorption capacity associated with higher available coagulant surface area, (iii) greater virus-floc binding affinity due to effective charge neutralization and hydrophobic interactions, and/or (iv) additional removal by a dynamic membrane if a thick cake layer of flocs is deposited.

The joint effects of efficacy and compliance: a study of household water treatment effectiveness against childhood diarrhea

The effectiveness of household water treatment (HWT) at reducing diarrheal disease is related to the efficacy of the HWT method at removing pathogens, how people comply with HWT, and the relative contributions of other pathogen exposure routes. We define compliance with HWT as the proportion of drinking water treated by a community. Although many HWT methods are efficacious at removing or inactivating pathogens, their effectiveness within actual communities is decreased by imperfect compliance. However, the quantitative relationship between compliance and effectiveness is poorly understood. To assess the effectiveness of HWT on childhood diarrhea incidence via drinking water for three pathogen types (bacterial, viral, and protozoan), we developed a quantitative microbial risk assessment (QMRA) model. We examined the relationship between log(10) removal values (LRVs) and compliance with HWT for scenarios varying by: baseline incidence of diarrhea; etiologic fraction of diarrhea by pathogen type; pattern of compliance within a community; and size of contamination spikes in source water. Benefits from increasing LRVs strongly depend on compliance. For perfect compliance, diarrheal incidence decreases as LRVs increase. However, if compliance is incomplete, there are diminishing returns from increasing LRVs in most of the scenarios we considered. Higher LRVs are more beneficial if: contamination spikes are large; contamination levels are generally high; or some people comply perfectly. The effectiveness of HWT interventions at the community level may be limited by imperfect compliance, such that the benefits of high LRVs are not realized. Compliance with HWT should be carefully measured during HWT field studies and HWT dissemination programs. Studies of pathogen concentrations in a variety of developing-country source waters are also needed. Guidelines are needed for measuring and promoting compliance with HWT.

Hands and water as vectors of diarrheal pathogens in Bagamoyo, Tanzania

Diarrheal disease is a leading cause of under-five childhood mortality worldwide, with at least half of these deaths occurring in sub-Saharan Africa. Transmission of diarrheal pathogens occurs through several exposure routes including drinking water and hands, but the relative importance of each route is not well understood. Using molecular methods, this study examines the relative importance of different exposure routes by measuring enteric bacteria (pathogenic Escherichia coli) and viruses (rotavirus, enterovirus, adenovirus) in hand rinses, stored water, and source waters in Bagamoyo, Tanzania. Viruses were most frequently found on hands, suggesting that hands are important vectors for viral illness. The occurrence of E. coli virulence genes (ECVG) was equivalent across all sample types, indicating that both water and hands are important for bacterial pathogen transmission. Fecal indicator bacteria and turbidity were good predictors of ECVG, whereas turbidity and human-specific Bacteroidales were good predictors of viruses. ECVG were more likely found in unimproved water sources, but both ECVG and viral genes were detected in improved water sources. ECVG were more likely found in stored water of households with unimproved sanitation facilities. The results provide insights into the distribution of pathogens in Tanzanian households and offer evidence that hand-washing and improved water management practices could alleviate viral and bacterial diarrhea.