Human enteric adenovirus F40/41 as a major cause of acute gastroenteritis in children in Brazil, 2018 to 2020

Co-occurrence of adeno-associated virus 2 and human enteric adenovirus (group F) in wastewater after worldwide outbreaks of acute hepatitis of unknown etiology (AHUE)

In 2022, several cases of acute hepatitis of unknown etiology (AHUE) have been associated with Adeno-associated virus 2 (AAV-2) and the common childhood virus Adenovirus 41 (AdV-41). This outbreak has resulted in serious complications in patients which included 5 % of individuals requiring a liver transplant and 22 deaths. Before these AHUE cases, no previous information had been reported regarding the co-infections and co-occurrence of these two viruses in the human population. The present study utilized WBE tools to investigate the prevalence of AAV-2 and AdV-F (AdV-41 and AdV-40) in wastewater from two different waste-water treatment plants (WWTP) serving the city of Bloomington in Southern Indiana, USA. The concentrations of AAV-2 and AdV-F were quantified using digital PCR in weekly wastewater samples taken over the duration of 18 months. High levels of both viruses were observed in most of the samples where co-detection and correlation in the concentrations for AAV-2 and AdV-F were found to be significant (p < 0.01) throughout duration of the study. In addition, significant seasonal changes were observed in the viral concentrations of both viruses (P < 0.01), but these seasonal variations were different between WWTPs (p < 0.01). However, these seasonal variations in viral concentrations were similar for both viruses. The sequences of AdV-F and AAV were obtained from the wastewater samples and confirmed the detection of AAV-2, AdV-41, and AdV-40 in the samples analyzed. Even though our study was done after the 2022 outbreak of AHUE, our results demonstrated the persistence of infections with both viruses in the population. It also highlights the ongoing spread of both viruses in the population and the importance of WBE in surveillance of these viruses.

Coinfection of human adenovirus and recombinant human astrovirus in a case of acute gastroenteritis: A report from China

Diarrhea is one of the major public health issues worldwide. Although the infections of individual enteric virus have been extensively studied, elucidation of the coinfection involving multiple viruses is still limited. In this study, we identified the coinfection of human adenovirus (HAdV) and human astrovirus (HAstV) in a child with acute gastroenteritis, analyzed their genotypes and molecular evolution characteristics. The sample was collected and identified using RT-PCR and subjected to whole-genome sequencing on the NovaSeq (Illumina) platform. Obtained sequences were assembled into the complete genome of HAdV and the ORF1 of HAstV. We conducted phylogenetic analysis using IQ-TREE software and conducted recombination analysis with the Recombination Detection Program. The sequenced HAdV was confirmed to be genotype 41, and was genetically close to some European strains. Phylogenetic analysis revealed that the HAstV was genetically close to both HAstV-2 and HAstV-4 and was different from the genotype prevalent in Shenzhen before. The recombination analysis confirmed that the sequenced HAstV strain is a recombinant of HAstV-2 and HAstV-4. Our analysis has shown that the strains in this coinfection are both uncommon variants in this geographical region, instead of dominant subtypes that have prevailed for years. This study presents a coinfection of HAdV and HAstV and conducts an evolutionary analysis on involved viruses, which reveals the genetic diversity of epidemic strains in Southern China and offers valuable insights into vaccine and medical research.

Multispecies Cocirculation of Adenoviruses Identified by Next-Generation Sequencing During an Acute Gastroenteritis Outbreak in Coastal Kenya in 2023

Background

Although 7 human adenovirus (HAdV) species are known to exist, only F (types 40 and 41) and G are identified as diarrheal disease agents. The role of other HAdV species in diarrheal disease remains unclear, and data on their prevalence are limited. We describe HAdV species and types in hospitalized children with diarrhea in coastal Kenya.

Methods

Three hundred twenty-nine stool samples collected between June 2022 and August 2023 from children aged <13 years were screened for HAdV using quantitative polymerase chain reaction (qPCR). Positive HAdV cases were genotyped by adenovirus primers from the RespiCoV panel by amplification, next-generation sequencing, and phylogenetic analysis.

Results

Sixty-five samples (20%) tested HadV positive, of which 5 HAdV species were identified. Other than HAdV F, other species included A, B, C, and D; these were detected as either mono-detections or coinfections. Six HAdV F identified by NGS had been missed by our qPCR typing method. This appeared to be as a result of a 133-nucleotide deletion in the long fiber protein, which abrogated a primer and probe binding site. Based on grading of diarrheal disease severity using VESIKARI scores, 93% of the HAdV cases presented with severe disease. One child with an HAdV F infection died.

Conclusions

Our study shows the enormous diversity and clinical characteristics of HAdV species in children with diarrhea in coastal Kenya. These data offer an opportunity to improve current diagnostic assays and increase knowledge of HAdV in Africa for control of outbreaks in the future.

Clinical characteristics and phylogenetic analysis of human enteric adenovirus type 41 (HAdV-F41) from children with gastroenteritis during SARS-CoV-2 pandemic

Human adenovirus type 41 (HAdV-F41) usually causes pediatrics gastroenteritis. However, it was reported to be associated with the outbreaks of severe acute hepatitis of unknown aetiology (SAHUA) in pediatrics during COVID-19 pandemic. In this study, we investigated the prevalence of enteric HAdV-F41 in 37,920 paediatric gastroenteritis cases from 2017 to 2022 in Guangzhou, China. All children presented were tested negative for SARS-CoV-2 during the "zero-COVID" period. The main clinical symptom of the children was diarrhea (96.5%). No fatalities nor liver abnormal symptoms was found. In 2021, one year since the pandemic of COVID-19, the prevalence of HAdV-F41 abruptly increased from 3.71% to 8.64% (P < 0.001). All of HAdV-F41 circulating worldwide were classified into eight different subtypes (G1-G8) based on the phylogenetic clustering permutation of the four capsid genes of HAdV-F41. G3 was the predominant subtype (56.2%; 77/137). CRV5 isolates from SAHUA cases belong to this subtype, in which N312D and H335D mutations in the short fiber knob were identified in both Guangzhou and CRV5 isolates, presumably changing the virus tropism by directly interacting with the heparin sulfate (HS) receptor. Additionally, a novel recombinant G6 subtype, which is unique and only circulating in China was first identified in this study. This is the first study highlighting the prevalence of HAdV-F41 in paediatric cases of gastroenteritis during COVID-19 pandemic in China. The clinical and viral evolution finding of HAdV-F41 provide insight into the clinical characteristics of children with HAdV-F41 infections as well as the uncertain role of HAdV-F41 in the cause of SAHUA.

Epidemiology and molecular detection of human adenovirus and non-polio enterovirus in fecal samples of children with acute gastroenteritis: A five-year surveillance in northern Brazil

Acute gastroenteritis (AGE) is a common pediatric infection that remains a significant cause of childhood morbidity and mortality worldwide, especially in low-income regions. Thus, the objective of this study was to detect human adenovirus (HAdV) and non-polio enterovirus (NPEV) in fecal samples from the Gastroenteritis Surveillance Network, and to identify circulating strains by nucleotide sequencing. A total of 801 fecal samples were tested using qPCR/RT-qPCR, and 657 (82.0%) were inoculated into HEp-2C and RD cell lines. The HAdV and NPEV positivity rates obtained using qPCR/RT-qPCR were 31.7% (254/801) and 10.5% (84/801), respectively, with 5.4% (43/801) co-detection. Cytopathic effect was observed in 9.6% (63/657) of patients, 2.7% (18/657) associated with HAdV, and 6.2% (41/657) associated with NPEV after testing by ICC-PCR. A comparison of the two methodologies demonstrated an agreement of 93.5% for EVNP and 64.4% for HAdV. These two viruses were detected throughout the study period, with HAdV positivity rates ranging from 41% in Amapá to 18% in Pará. The NEPV varied from 18% in Pará/Rondônia to 3% in Acre. The most affected age group was over 60 months for both HAdV and NPEV. Samples previously positive for rotavirus and norovirus, which did not show a major difference in the presence or absence of diarrhea, fever, and vomiting, were excluded from the clinical analyses of these two viruses. These viruses circulated over five years, with a few months of absence, mainly during the months corresponding to the waves of SARS-CoV-2 infection in Brazil. Five HAdV species were identified (A, B, C, D, and F), with a greater predominance of HAdV-F41 (56.5%) followed by HAdV-C (15.2%). Three NPEV species (A, B, and C) were detected, with serotypes E14 (19.3%) and CVA-24 (16.1%) being the most prevalent. The present study revealed a high diversity of NPEV and HAdV types circulating in children with AGE symptoms in the northern region of Brazil.

Enteropathogenic viruses associated with acute gastroenteritis among African children under 5 years of age: A systematic review and meta-analysis

Gastroenteritis viruses are the leading etiologic agents of diarrhea in children worldwide. We present data from thirty-three (33) eligible studies published between 2003 and 2023 from African countries bearing the brunt of the virus-associated diarrheal mortality. Random effects meta-analysis with proportion, subgroups, and meta-regression analyses were employed. Overall, rotavirus with estimated pooled prevalence of 31.0 % (95 % CI 24.0-39.0) predominated in all primary care visits and hospitalizations, followed by norovirus, adenovirus, sapovirus, astrovirus, and aichivirus with pooled prevalence estimated at 15.0 % (95 % CI 12.0-20.0), 10 % (95 % CI 6-15), 4.0 % (95 % CI 2.0-6.0), 4 % (95 % CI 3-6), and 2.3 % (95 % CI 1-3), respectively. Predominant rotavirus genotype was G1P[8] (39 %), followed by G3P[8] (11.7 %), G9P[8] (8.7 %), and G2P[4] (7.1 %); although, unusual genotypes were also observed, including G3P[6] (2.7 %), G8P[6] (1.7 %), G1P[6] (1.5 %), G10P[8] (0.9 %), G8P[4] (0.5 %), and G4P[8] (0.4 %). The genogroup II norovirus predominated over the genogroup I-associated infections (84.6 %, 613/725 vs 14.9 %, 108/725), with the GII.4 (79.3 %) being the most prevalent circulating genotype. In conclusion, this review showed that rotavirus remains the leading driver of viral diarrhea requiring health care visits and hospitalization among under-five years children in Africa. Thus, improved rotavirus vaccination in the region and surveillance to determine the residual burden of rotavirus and the evolving trend of other enteric viruses are needed for effective control and management of cases.

Human adenoviruses in children with gastroenteritis: a systematic review and meta-analysis

PURPOSE

Human adenoviruses (HAdVs) have always been suggested as one of the main causes of gastroenteritis in children. However, no comprehensive report on the global epidemiology of these viruses in pediatric gastroenteritis is available.

METHODS

A systematic search was conducted to obtain published papers from 2003 to 2023 in three main databases PubMed, Scopus, and Web of Science.

RESULTS

The estimated global pooled prevalence of HAdV infection in children with gastroenteritis was 10% (95% CI: 9-11%), with a growing trend after 2010. The highest prevalence was observed in Africa (20%, 95% CI: 14-26%). The prevalence was higher in inpatients (11%; 95% CI: 8-13%) and patients aged 5 years old and younger (9%; 95% CI: 7-10%). However, no significant difference was observed between male and female patients (P = 0.63). The most prevalent species was found to be the species F (57%; 95% CI: 41-72%). The most common HAdVs observed in children with gastroenteritis were types 40/41, 38, and 2. Analysis of case-control studies showed an association between HAdV and gastroenteritis in children (OR: 2.28, 95% CI; 1.51-3.44).

CONCLUSION

This study provided valuable insights into the importance of HAdVs in children with gastroenteritis, especially in hospitalized and younger children. The results can be used in future preventive measurements and the development of effective vaccines.

Remarkable increase in the detection and molecular characterization of adenovirus F41 in children with acute gastroenteritis in Japan, 2017-2023

Human adenovirus (HAdV) is one of the causative viruses of acute gastroenteritis (AGE) in children worldwide. Species F is known to be enteric adenovirus (genotypes 40 and 41) detected in stool samples. In Japan, we conducted an epidemiological study and molecular characterization of HAdV before and after the COVID-19 pandemic from 2017 to 2023. Among 821 patients, HAdV was detected in 118 AGE cases (14.4%). During a period of 6 years, the HAdV detection rates for each year were relatively low at 3.7% and 0%, in 2017-2018, and 2020-2021, respectively. However, the detection rate increased to remarkably high rates, ranging from 13.3% to 27.3% in the other 4-year periods. Of these HAdV-positive strains, 83.1% were F41 genotypes and 16.9% were other genotypes (A31, B3, C1, C2/C6, and C5). Phylogenetic analyses of the nucleotide and deduced amino acid sequences of the full-length hexon gene demonstrated that HAdV-F41 strains were comprised of three clades, and each clade was distributed across the study period from 2017 to 2023. Analysis of deduced amino acid sequences of the hexon gene of the representative HAdV-F41 strains from each clade revealed numerous amino acid substitutions across hypervariable regions (HVRs) from HVR-1 to HVR-7, two insertions in HVR-1 and HVR-7, and two deletions in HVR-1 and HVR-2 of the hexon gene compared to those of the prototype strain, particularly, those of clade 3 HAdV-F41 strains. The findings suggested that the HAdV-F41 of each clade was stable, conserved, and co-circulated for over two decades in Japan.

Effect of COVID-19 protective measures on the epidemiology characteristics of rotavirus, adenovirus, and coinfections among pediatric patients with acute gastroenteritis in Hangzhou, China

Human rotavirus (RV) and adenovirus (AdV) have been recognized as common enteric viruses associated with viral acute gastroenteritis (AGE) in children aged<5 years. However, with the transmission of coronavirus disease 2019 (COVID-19) has been suppressed due to various aggressive and effective anti-epidemic measures, the prevalence of other viruses has also been affected. Therefore, this study aimed to investigate the impact of COVID-19 on the epidemiological characterization of RV, AdV, and coinfections among children with AGE in a hospital in Hangzhou from 2019 to 2023. The overall changes, seasonal distribution, and age distribution of enteroviruses were analyzed based on 5 years of records. All data were analyzed using SPSS 27.0. A total of 102,049 samples were analyzed from January 2019 to August 2023, and among them 15,911 (15.59%) were positive specimens, 11,646 (11.41%) were RV-positive, 4,057 (3.98%) were AdV-positive, and 208 (0.20%) were coinfection. The positive rate among males was 15.54%, while among females was 15.66% with a male-to-female ratio of 1.42:1. There was no significant difference in the positive rates of enterovirus infection between males and females. Significant associations were found between the month group and RV/AdV infection, with RV detection peaking in winter (74.18%) and early spring (29.22%), while AdV has a high prevalence in summer (16.03%) and spring (12.71%). The age group was also found to be significantly associated with RV/AdV infection, with RV being most prevalent in the 1-3-year-old age group (16.99%), while AdV was highest in the 3-5-year-old age group (8.10%).IMPORTANCEThis study highlights the epidemiological changes of rotavirus (RV), adenovirus (AdV), and coinfections in children with acute gastroenteritis (AGE) before, during, and after coronavirus disease 2019 (COVID-19) periods. There was a highly statistically significant difference in the positive rates of RV-positive, AdV-positive, and coinfection (P < 0.001), indicating that RV remains the main pathogen causing AGE. It emphasizes the importance of continuous surveillance of RV and AdV at both local and global levels. Regular surveillance of prevalent rotavirus strains will facilitate the development of new inactivated rotavirus vaccines and aid in disease prevention and control.

Viral gastroenteritis

Since the discovery of norovirus in 1972 as a cause of what was contemporarily known as acute infectious non-bacterial gastroenteritis, scientific understanding of the viral gastroenteritides has continued to evolve. It is now recognised that a small number of viruses are the predominant cause of acute gastroenteritis worldwide, in both high-income and low-income settings. Although treatment is still largely restricted to the replacement of fluid and electrolytes, improved diagnostics have allowed attribution of illness, enabling both targeted treatment of individual patients and prioritisation of interventions for populations worldwide. Questions remain regarding specific genetic and immunological factors underlying host susceptibility, and the optimal clinical management of patients who are susceptible to severe or prolonged manifestations of disease. Meanwhile, the worldwide implementation of rotavirus vaccines has led to substantial reductions in morbidity and mortality, and spurred interest in vaccine development to diminish the impact of the most prevalent viruses that are implicated in this syndrome.

Assessment of Gastroenteric Viruses in Marketed Bivalve Mollusks in the Tourist Cities of Rio de Janeiro, Brazil, 2022

This study investigated the prevalence and genetic diversity of gastroenteric viruses in mussels and oysters in Rio de Janeiro, Brazil. One hundred and thirty-four marketed bivalve samples were obtained between January and December 2022. The viral analysis was performed according to ISO/TS 15216, and the screening revealed the detection of norovirus GII/GI (40.3%), sapovirus (SaV; 12.7%), human mastadenovirus (7.5%), and rotavirus A (RVA; 5.9%). In total, 44.8% (60) of shellfish samples tested positive for one or more viruses, 46.7% (28/60) of the positive samples tested positive for a single viral agent, 26.7% (16) tested positive for two viral agents, 8.3% (5) for three viral agents, and 13.3% (8) for four viral agents. Additionally, three mussel samples were contaminated with the five investigated viruses (5%, 3/60). Norovirus GII showed the highest mean viral load (3.4 × 105 GC/g), followed by SaV (1.4 × 104 GC/g), RVA (1.1 × 104 GC/g), human mastadenovirus (3.9 × 103 GC/g), and norovirus GI (6.7 × 102 GC/g). Molecular characterization revealed that the recovered norovirus strains belonged to genotypes GII.2, GII.6, GII.9, GII.17, and GII.27; SaV belonged to genotypes GI.1 and GIV.1; RVA to genotypes G6, G8, P[8]-III, and human mastadenovirus to types F40 and F41. The GII.27 norovirus characterized in this study is the only strain of this genotype reported in Brazil. This study highlights the dissemination and diversity of gastroenteric viruses present in commercialized bivalves in a touristic area, indicating the potential risk to human health and the contribution of bivalves in the propagation of emerging pathogens.

Detection and complete genome sequence analysis of human adenovirus in children with acute diarrhea in Yunnan, China, 2015-2021

The aims of this study were to determine the distribution and prevalence of gastroenteritis caused by human adenovirus (HAdV) in children in Yunnan province, China, in 2015-2021 and to identify preventive measures that can be taken to reduce morbidity and mortality in children.HAdV is a significant agent of diarrhea in children, but limited data are available regarding the epidemiology and genetic diversity of HAdV in children with diarrhea in Yunnan province, China. A total of 1754 fecal samples were subjected to real-time RT-PCR to detect and quantify HAdV. Positive samples were further analyzed using next-generation sequencing (NGS), and epidemiological data were analyzed as well.1754 patients with diarrhea were enrolled, of which 1041 were male and 713 were female (M:F ratio: 1.46). Seventy-two stool samples out of 1754 (4.10%) were positive for HAdV. The detection rates of all age groups varied from 2.50-4.78%. The highest incidence of HAdV was observed in children under 2 years of age, especially in children 12-24 months-old. From 2015-2021, the annual detection rate ranged from 1.62-12.26%. HAdV was detected throughout the year, but with marked seasonality. Children were most likely to be positive for HAdV in June and November. We detected HAdV in 15.53% (16/103) of samples collected in June and in 8.19% (14/171) of those collected in November. The entire viral genome was successfully sequenced for 13 of the 72 HAdV-positive samples, and 76.92% (10/13) of these were classified as genotype F41 and 23.08% (3/13) were classified as genotype C2.ConclusionsIn Yunnan province, children of all ages are susceptible to HAdV infection, but there has been marked variation in the yearly prevalence. The highest rate of HAdV detection was in June, followed by November. Priority should be given to disease prevention over the development of targeted antiviral therapies, and effective vaccines for preventing HAdV diarrhea are needed. It is also important to establish a surveillance system to collect relevant clinical and epidemiological data quickly in order to assess the potential risk of HAdV infection in children and to identify epidemic strains for the development of effective vaccines.

Circulation of adenovirus and other viruses in urban drainage channels: an environmental surveillance in Belém, Amazon region, Brazil

Urban channels in amazon cities are very polluted, with garbage and sewage disposal in these aquatic environments, favoring the high dissemination of waterborne viruses such as human adenovirus (HAdV). The aim of this study was to perform the detection and molecular characterization of adenovirus in urban channels and in a wastewater treatment plant located in a metropolitan city in the Amazon. Additionally, metagenomic analyses were performed to assess viral diversity. Samples were concentrated by organic flocculation, analyzed by quantitative real time PCR (qPCR) and sequenced (Sanger e next generation sequencing). Cell culture was performed to verify the viability of HAdV particles. A total of 104 samples were collected, being the HAdV positivity of 76% (79/104). Among the positive samples, 29.1% (23/79) were characterized as HAdV-F40 (87%, 20/23), HAdV-F41 (8.7%, 2/23), and HAdV-B (4.3%, 1/23). Average precipitation rates ranged from 163 to 614 mm, while the pH ranged from 6.9 to 7.6. Eight positive samples were inoculated into A549 cells and in 4 of these, was observed changes in the structure of the cell monolayer, alteration in the structure of the cell monolayer was observed, but without amplification when analyzed by PCR. The metagenomic data demonstrated the presence of 14 viral families, being the most abundant: Myoviridae (41% of available reads), Siphoviridae (24.5%), Podoviridae (14.1%), and Autographiviridae (6.9%) with more than 85% of the total number of identified reads. This study reinforcing that continuous surveillance may contribute to monitoring viral diversity in aquatic environments and provide early warning of potential outbreaks.

Molecular characterization of human adenovirus causing infantile acute gastroenteritis in Venezuela before and after rotavirus vaccine implementation

Human adenoviruses (HAdV) of species F are commonly involved in pediatric acute gastroenteritis (AGE). The real impact on Venezuelan health is unknown. To investigate the prevalence and molecular diversity of HAdV in Venezuela, 630 fecal samples collected from children with AGE in 3 cities, from 2001 to 2013, were tested by PCR. Species F and types F40/41 were identified by REA. HAdV was detected in 123 cases (19.5%), most from outpatient females under 24 months old. A progressive and substantial increase in the detection rate was observed over time, significantly higher in rotavirus vaccinated than unvaccinated children (28.4% vs. 9.5%, P = 0.00019). Phylogenetic analysis of 28 randomly selected genomes showed high similarity among HAdV-F40/41 and those worldwide. HAdV-F of type 41 prevailed (79.8%) and clustered into 2 intratypic major clades. The significant involvement of HAdV-F41 in AGE suggests the importance of actively monitoring viral agents other than rotavirus, especially after vaccine introduction.

Establishment of Digital PCR Method and Reference Material for Adenoviruses 40 and 41

Coinfection with human adenovirus (HAdV) and SARS-CoV-2 has been associated with acute hepatitis in children with unknown etiology. Similar cases have been reported in many countries, and HAdV 40 and HAdV 41 have been identified. The quantification method is established based on digital PCR (dPCR) for HAdV 40/41, which is more convenient for low-concentration virus detection. The limit of detections of HAdV 40/41 dPCR were 4 and 5 copies/μL. Pseudovirus reference material (RM) that contains the highly conserved HEXON gene was developed and quantified with the dPCR method. The assigned values with expanded uncertainty were (1.43 ± 0.35) × 103 copies/μL for HAdV 40 RM and (1.21 ± 0.28) × 103 copies/μL for HAdV 41 RM. The values could be reproduced on multiple platforms. The dPCR method and pseudovirus RMs contribute to the improved accuracy of HAdV 40/41 detection, which is crucial for clinical diagnosis.

Significantly Longer Shedding of Norovirus Compared to Rotavirus and Adenovirus in Children with Acute Gastroenteritis

Worldwide, acute gastroenteritis (AGE) is a major cause of morbidity and mortality in children under 5 years of age. Viruses, including norovirus, rotavirus, and enteric adenovirus, are the leading causes of pediatric AGE. In this prospective cohort study, we investigated the viral load and duration of shedding of norovirus, rotavirus, and adenovirus in stool samples collected from 173 children (median age: 15 months) with AGE who presented to emergency departments (EDs) across Canada on Day 0 (day of enrollment), and 5 and 28 days after enrollment. Quantitative RT-qPCR was performed to assess the viral load. On Day 0, norovirus viral load was significantly lower compared to that of rotavirus and adenovirus (p < 0.001). However, on Days 5 and 28, the viral load of norovirus was higher than that of adenovirus and rotavirus (p < 0.05). On Day 28, norovirus was detected in 70% (35/50) of children who submitted stool specimens, while rotavirus and adenovirus were detected in 52.4% (11/24) and 13.6% (3/22) of children (p < 0.001), respectively. Overall, in stool samples of children with AGE who presented to EDs, rotavirus and adenovirus had higher viral loads at presentation compared to norovirus; however, norovirus was shed in stool for the longest duration.

Surveillance and epidemiological characterization of human adenovirus infections among outpatient children with acute gastroenteritis during the COVID-19 epidemic in Shanghai, China

BACKGROUND

Human adenovirus (HAdV) has been recognized as one of the common enteric viruses associated with acute gastroenteritis (AGE) in children. The aim of this study was carried out to illustrate the epidemiological characterization of HAdV Infections among children younger than 15 years in Shanghai during COVID-19.

METHODS

During May 2020 and April 2022, 1048 fecal samples were collected from children ≤ 15 years diagnosed with AGE in the Children's Hospital of Fudan University. HAdV was identified by PCR and sequenced with specific primers. All the obtained sequences were analyzed by MEGA (version 6.0). Demographic information and clinical features data were also collected and analyzed.

RESULTS

In total, 97 (9.3%, 97/1048) samples were detected to be HAdV during May 2020 and April 2022. We found an atypical upsurge in HAdV infection in the year 2021 after a major suppression in the year 2020. Approximately 84.5% (82/97) of HAdV-infected children were aged 0-60 months. Among the 97 HAdV-positive samples, only two species and five genotypes were detected. HAdV-F (88.7%, 86/97) was the most prevalent species and HAdV-F41 (87.6%, 85/97) was the most common genotype. Diarrhea, vomiting, and fever were the main clinical manifestations in children infected with HAdV. The children aged from 0 to 12 months showed simpler patterns of clinical presentation than those of children older than 13 months.

CONCLUSIONS

Our findings described the epidemiological changes of HAdV infection in children with AGE during the COVID-19, which further underscored the importance of continuous surveillance of HAdV at both local and global scales.

Enteric and non-enteric adenoviruses in children with acute gastroenteritis in Western India

Human adenoviruses (HAdVs) are the viral agents responsible for a wide spectrum of acute and chronic diseases. HAdVs are the most important etiological agents of acute gastroenteritis (AGE) and are identified as the major contributor to the deaths of diarrheal children globally. The significant rise in HAdV infections in rotavirus-vaccinated children documented in multiple studies demands continuous monitoring of HAdV strains. After the inclusion of rotavirus vaccines in the immunization schedule of India, public health research regarding prevalence, etiology, and risk factors is highly necessary for evidence-based policies and their implementation to sustain diarrhea prevention programs. In the present study, children admitted for AGE between 2013 and 2016 in seven different hospitals in Maharashtra and Gujrat states of Western India were subjected for investigation. HAdVs were found in 5.2% of the fecal specimens with the dominance of species-F (52.4%) strains, followed by the occurrence of non-enteric adenoviruses of species A (17.4%), C (11.4%), B (8.2%), and D (3.2%). The species-F strains were predominant in Ahmadabad (78.5%), Mumbai (61.5%), and Surat (57.1%) cities, followed by species-A strains. In Pune city, species B strains were detected in all HAdV patients, with none of the species A strains. Clinically, patients infected with enteric and non-enteric HAdV strains were indistinguishable. However, a high viral load was observed in species-F specimens as compared to non-species-F. The present study on fecal specimens collected in the pre-rotavirus vaccination era from hospitalized AGE patients will be important for future comparative analysis to know the exact impact of vaccination in children of Western India.

May 2022 acute hepatitis outbreak, is there a role for COVID-19 and other viruses?

There has been an increasing number of reported cases of acute hepatitis of unknown origin in previously healthy children since first reported on March 31, 2022. This clinical syndrome is identified by jaundice and markedly elevated liver enzymes with increased aspartate transaminase and/or alanine aminotransaminase (greater than 500 IU/L). We conducted an inclusive literature review with respect to acute hepatitis outbreaks in children using the search terms acute hepatitis, outbreak, children, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), coronavirus disease 2019 (COVID-19), and adenovirus. According to the cumulative data presented in four main studies, the median age is 4 years, with a male predominance (1.3:1). Jaundice was the most common clinical manifestation (69%), followed by vomiting (63%), anorexia (52.9%), diarrhea (47.2%), abdominal pain (39%), pyrexia (33.3%), pale stool (30%), and dark urine (30%). Coryza and lethargy were reported in 16.6%, while pruritus was reported in 2% of cases. Acute liver failure was observed in 25% of cases. The exact mechanism of this acute hepatitis outbreak is still not entirely clear. Adenoviruses and SARS-CoV-2 were detected in a significant number of patients. Coinfection with adenovirus and SARS-CoV-2 could be a possible underlying mechanism. However, other possible infections and mechanisms must be considered in the pathogenesis of this condition. Acute hepatitis of unknown origin in children has been a serious problem since the start of the COVID-19 pandemic but has not yet been sufficiently addressed. Many questions remain regarding the underlying mechanisms leading to acute liver failure in children, and it is likely that extensive future research is needed.

Adenoviruses in medicine: innocuous pathogen, predator, or partner

The consequences of human adenovirus (HAdV) infections are generally mild. However, despite the perception that HAdVs are harmless, infections can cause severe disease in certain individuals, including newborns, the immunocompromised, and those with pre-existing conditions, including respiratory or cardiac disease. In addition, HAdV outbreaks remain relatively common events and the recent emergence of more pathogenic genomic variants of various genotypes has been well documented. Coupled with evidence of zoonotic transmission, interspecies recombination, and the lack of approved AdV antivirals or widely available vaccines, HAdVs remain a threat to public health. At the same time, the detailed understanding of AdV biology garnered over nearly 7 decades of study has made this group of viruses a molecular workhorse for vaccine and gene therapy applications.

Detection and Molecular Characterization of Enteric Viruses in Bivalve Mollusks Collected in Arraial do Cabo, Rio de Janeiro, Brazil

Viral bivalve contamination is a recognized food safety hazard. Therefore, this study investigated the detection rates, seasonality, quantification, and genetic diversity of enteric viruses in bivalve samples (mussels and oysters). We collected 97 shellfish samples between March 2018 and February 2020. The screening of samples by qPCR or RT-qPCR revealed the detection of norovirus (42.3%), rotavirus A (RVA; 16.5%), human adenovirus (HAdV; 24.7%), and human bocavirus (HBoV; 13.4%). There was no detection of hepatitis A virus. In total, 58.8% of shellfish samples tested positive for one or more viruses, with 42.1% of positive samples contaminated with two or more viruses. Norovirus showed the highest median viral load (3.3 × 106 GC/g), followed by HAdV (median of 3.5 × 104 GC/g), RVA (median of 1.5 × 103 GC/g), and HBoV (median of 1.3 × 103 GC/g). Phylogenetic analysis revealed that norovirus strains belonged to genotype GII.12[P16], RVA to genotype I2, HAdV to types -C2, -C5, and -F40, and HBoV to genotypes -1 and -2. Our results demonstrate the viral contamination of bivalves, emphasizing the need for virological monitoring programs to ensure the quality and safety of shellfish for human consumption and as a valuable surveillance tool to monitor emerging viruses and novel variants.