Epidemiology of enteric viruses in children with gastroenteritis in Ogun State, Nigeria

Epidemiology of norovirus infection in Nigeria: a systematic review and meta-analysis

Human norovirus (HuNoV) is responsible for most cases of gastroenteritis worldwide, but information about the prevalence and diversity of HuNoV infections in lower-income settings is lacking. In order to provide more information about the burden and distribution of norovirus in Nigeria, we systematically reviewed original published research articles on the prevalence of HuNoV in Nigeria by accessing databases, including PubMed, Web of Science, ScienceDirect, Google Scholar, and African Journals Online (AJOL). The protocol for the review was registered on PROSPERO (registration number CRD42022308857). Thirteen relevant articles were included in the review, and 10 of them were used for meta-analysis. The pooled prevalence of HuNoV-associated gastroenteritis among children below 5 years of age in Nigeria, determined using the random-effects model, was 10.9% (95% CI, 6.7-16.7%). Among children below the age of 5 presenting with HuNoV infections, the highest prevalence was in children ≤2 years old (n = 127, 83%). The prevalence of HuNoV infections was seen to decrease with increasing age. In addition, HuNoV was detected in asymptomatic food handlers, bats, and seafoods. A total of 85 sequences of HuNoV isolates from Nigeria have been determined, and based on those sequences, the most prevalent norovirus genogroup was GII (84%). Genotypes GII.4 and GI.3 were the most frequently identified genotypes, with GII.4 constituting 46% of all of the HuNoVs identified in Nigeria. These results suggest a risk associated with cocirculation of emerging variants with known genotypes because of their recombination potential. Larger molecular epidemiological studies are still needed to fully understand the extent and pattern of circulation of HuNoVs in Nigeria.

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.

Detection and genetic diversity of parechoviruses in children with acute flaccid paralysis in Cameroon

Human Parechoviruses (HPeVs) have rarely been considered in the virological investigation of Acute Flacid Paralysis (AFP) cases in Africa, where enteric infections are very common. This study investigated the prevalence and genetic diversity of HPeV in 200 children aged ≤ 15 years with AFP in Cameroon from 2018 to 2019. HPeVs were detected in their faecal RNA using 5'-untranslated real-time RT-PCR. Detected HPeVs were typed by phylogenetic comparison with homologous sequences from homotypic reference strains. Overall, HPeV RNA was detected in 11.0% (22/200) of the 200 stool samples tested. Twelve HPeVs were successfully sequenced and reliably assigned to HPeV-A1, A4, A5, A10, A14, A15, A17 and A18 genotypes. Phylogenetic analyses revealed a high genetic variability among the studied HPeVs, as well as between the studied HPeVs and their previously reported counterparts from Cameroon in 2014. These findings suggest that different HPeV genotypes co-circulate in Cameroon without documented epidemics.

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.

Common and Potential Emerging Foodborne Viruses: A Comprehensive Review

Human viruses and viruses from animals can cause illnesses in humans after the consumption of contaminated food or water. Contamination may occur during preparation by infected food handlers, during food production because of unsuitably controlled working conditions, or following the consumption of animal-based foods contaminated by a zoonotic virus. This review discussed the recent information available on the general and clinical characteristics of viruses, viral foodborne outbreaks and control strategies to prevent the viral contamination of food products and water. Viruses are responsible for the greatest number of illnesses from outbreaks caused by food, and risk assessment experts regard them as a high food safety priority. This concern is well founded, since a significant increase in viral foodborne outbreaks has occurred over the past 20 years. Norovirus, hepatitis A and E viruses, rotavirus, astrovirus, adenovirus, and sapovirus are the major common viruses associated with water or foodborne illness outbreaks. It is also suspected that many human viruses including Aichi virus, Nipah virus, tick-borne encephalitis virus, H5N1 avian influenza viruses, and coronaviruses (SARS-CoV-1, SARS-CoV-2 and MERS-CoV) also have the potential to be transmitted via food products. It is evident that the adoption of strict hygienic food processing measures from farm to table is required to prevent viruses from contaminating our food.

Screening for viral pathogens in the gastrointestinal tract from cases of sudden unexpected death in infancy at the Tygerberg Medico-legal Mortuary

Sudden and unexpected death in infancy (SUDI) may be triggered by an external risk or exposure. Intestinal infections with enteric viruses may disrupt the gut and enhance bacterial toxins present in SUDI cases. While diarrhoeal disease deaths have decreased worldwide, approximately half a million deaths still occur in children in Sub- Saharan Africa and South Asia. Furthermore, the role of viral enteropathogens in SUDI cases have not been investigated. The aim of this study was to describe specific viral pathogens in stool samples collected from SUDI cases and age-matched, apparently healthy infants in Cape Town, South Africa. Stool samples were collected from 176 SUDI cases between June 2017 and May 2018. In addition, stool samples were collected from the nappies of 30 age-matched, apparently healthy infants as a control group. Real-time polymerase chain reaction was performed on the stool samples for viral detection. A total of 111 SUDI cases were positive for viruses, with rotavirus (38.6%; 68/176) and norovirus GI and GII (30.0%; 53/176) were prevalent in SUDI cases. Adenovirus Type F was present in only 15.9% (28/176), astrovirus in 9.7% (17/176), and sapovirus in 0.6% (1/176) of cases. In the control samples, norovirus GII was detected most frequently (36.7%; 11/30), followed by rotavirus (33.3%; 10/30), and sapovirus in 6.7% (2/30). While there was no significant association between SUDI cases and enteric viruses, the majority of viruses were significantly associated with the seasons. The study confirms the importance of rotavirus vaccination and describes the significance of norovirus infection in children, post rotavirus vaccine introduction.

Vaccine value profile for norovirus

Norovirus is attributed to nearly 1 out of every 5 episodes of diarrheal disease globally and is estimated to cause approximately 200,000 deaths annually worldwide, with 70,000 or more among children in developing countries. Noroviruses remain a leading cause of sporadic disease and outbreaks of acute gastroenteritis even in industrialized settings, highlighting that improved hygiene and sanitation alone may not be fully effective in controlling norovirus. Strengths in global progress towards a Norovirus vaccine include a diverse though not deep pipeline which includes multiple approaches, including some with proven technology platforms (e.g., VLP-based HPV vaccines). However, several gaps in knowledge persist, including a fulsome mechanistic understanding of how the virus attaches to human host cells, internalizes, and induces disease.

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.

Diverse genotypes of human enteric and non-enteric adenoviruses circulating in children hospitalized with acute gastroenteritis in Thailand, from 2018 to 2021

Human adenovirus (HAdV) is a common viral pathogen that causes diarrhea in children worldwide. The aim of this study was to investigate the prevalence and genotype diversity of HAdV strains circulating in children admitted to the hospitals with acute gastroenteritis (AGE) in Chiang Mai, Thailand, from 2018 to 2021. A total of 1,790 stool samples were screened for HAdV by PCR method, and 80 (4.5%) were positive for HAdV. Of these, children under 5 years of age accounted for 90.0% of HAdV-positive cases with the highest infection rate at the age group of 48-60 months old. The infection rate was not significantly different between boys and girls. The HAdV infection was detected sporadically throughout the year without a discrete seasonal pattern. Five species of both enteric and non-enteric HAdVs (A, B, C, E, and F) with 10 different genotypes, including HAdV-F41 (25.0%), HAdV-B3 (17.5%), HAdV-F40 (16.3%), HAdV-C1 (15.0%), HAdV-C5 (7.5%), HAdV-C2 (6.3%), HAdV-B7 (5.0%), HAdV-A12 (3.8%), HAdV-E4 (2.5%), and HAdV-B11 (1.3%), were detected in this study. In conclusion, our study reported the prevalence and seasonality of HAdV infection with a wide variety of HAdV genotypes circulating in children hospitalized with AGE during a period of 2018-2021 in Chiang Mai, Thailand. IMPORTANCE In the present study, the prevalence of human adenovirus (HAdV) infection in children with acute gastroenteritis (AGE) in Chiang Mai, Thailand, from 2018 to 2021 was detected at 4.5%. Diverse species and genotypes of HAdVs (HAdV-A12, HAdV-B3, HAdV-B7, HAdV-B11, HAdV-C1, HAdV-C2, HAdV-C5, HAdV-E4, HAdV-F40, and HAdV-F41) had been identified. The highest infection rate was found in children aged 48-60 months old. The HAdV infection was detected sporadically throughout the year. These findings imply that a wide variety of HAdV genotypes circulate in pediatric patients with AGE in Chiang Mai, Thailand.

Worldwide prevalence and genotype distribution of human astrovirus in gastroenteritis patients: A systematic review and meta-analysis

AIM

Human astrovirus (HAstV) is an important causative agent of gastroenteritis in humans, which mainly infects young children and the elderly. The goal of this study was to conduct a meta-analytic review of the prevalence of HAstV amongst patients with gastroenteritis, and to shed light on the connection between HAstV infection and gastroenteritis.

METHODS

Systematic literature searches were conducted to identify all potentially relevant studies recorded up to April 8th, 2022. For study weighting, the inverse variance method was employed and the random-effects model was applied to evaluate data. For case-control studies, the pooled odds ratio (OR) and 95% confidence interval (CI) were calculated to establish the relationship between HAstV infection and gastroenteritis.

RESULTS

Among 302423 gastroenteritis patients from 69 different countries, the overall pooled prevalence of HAstV infection was 3.48% (95% CI: 3.11%-3.89%). Case-control approach was used in 39 investigations, and the overall prevalence of HAstV infection among the 11342 healthy controls was 2.01% (95% CI: 1.40%-2.89%). Gastroenteritis and HAstV infection were associated with a pooled OR of 2.16 (95% CI: 1.72-2.71; P < 0.0001; I² = 33.7%). The most commonly found HAstV genotypes in gastroenteritis patients were HAstV1 (62.18%), HAstV7 (33.33%), and HAstV-MLB1 (17.43%).

CONCLUSION

The frequency of HAstV infection was the highest in children under the age of five, and in developing countries. The prevalence rate of HAstV was not influenced by gender. Semi-nested and nested RT-PCR were highly sensitive assays for detecting HAstV infections.

Molecular Epidemiology and Surveillance of Human Adenovirus and Rotavirus A Associated Gastroenteritis in Riyadh, Saudi Arabia

In Saudi Arabia, acute gastroenteritis (GE) is a common illness affecting children and adults; however, the extent to which human rotavirus A (HRV) and human adenovirus (HAdV) strains contribute to the condition is unclear. The surveillance of the GE-causing viruses, HRV and HadV, was performed using polymerase chain reaction, sequencing, and phylogenetic analysis at King Khalid University Hospital. The associations between virus prevalence and meteorological factors were analyzed. The prevalence of HAdV was recorded (7%), followed by HRV (2%). On a gender basis, HAdV infections were found to be dominant in females (5:2) (U = 407.5; p < 0.0001), whereas HRV was only detected in males (U = 50; p < 0.0001). A significantly higher HAdV prevalence was recorded at the age of 3.5 ± 0.63 years (21.1%; p = 0.00047), whereas HRV cases were found equally distributed between <3 years and 3-5 years. The highest HAdV prevalence was recorded in autumn, followed by winter and spring. A significant correlation was detected between humidity and the total number of recorded cases (p = 0.011). Phylogenetic analysis depicted the dominance of HAdV type 41 and the G2 lineage of HRV among circulating strains. The current study uncovered the epidemiology and genotypes of HRV and HadV, and provided forecasting equations for monitoring climatic-mediated outbreaks.

A Comparative Study of Acute Gastroenteritis Symptoms in Single- versus Multiple-Virus Infections

Many different enteric viruses can cause acute gastroenteritis in humans worldwide. While a single virus can indeed cause disease, multiple-virus infections are commonly reported. However, data regarding a comparison between single- and multiple-virus infections upon clinical manifestations of acute gastroenteritis are relatively limited. In this study, a total of 2383 fecal specimens were collected from children with acute gastroenteritis during June 2014-July 2017 in a pediatric clinic in Japan and tested for 11 viruses by multiplex RT-PCR. At least 1 virus was found in 1706 (71.6%) specimens and norovirus GII was the most frequent agent, followed by rotavirus A and other viruses. Multiple-virus infections were identified in 565 cases (33.1%). While major clinical symptoms were found to be significantly different in some single- vs. multiple-virus infections, the disease severity was statistically non-significant. Our study highlights the burden of multiple-virus infections for acute gastroenteritis and the clinical features of patients with multiple-virus infections.

Prevalence and relative risk of Rotavirus Gastroenteritis in children under five years in Nigeria: a systematic review and meta-analysis

Rotavirus is responsible for most cases of gastroenteritis and mortality in children below 5 years of age, especially in developing countries, including Nigeria. Nonetheless, there is limited data on the nationwide estimate for the prevalence of rotavirus. This systematic review and meta-analysis sought to determine the pooled prevalence of rotavirus infections and its relative risk among children below 5 years of age in Nigeria. Eligible published studies between 1982 and 2021 were accessed from 'PubMed', 'Science Direct', 'Google Scholar' and 'African Journal Online', 'Web of Science', 'Springer', 'Wiley' were systematically reviewed. The pooled prevalence, relative risk and regional subgroup analyses were calculated using the random effects model at 95% confidence interval (CI). A total of 62 selected studies, including 15 studies case-control studies, were processed in this review from a pooled population of 18,849 children. The nationwide pooled prevalence of rotavirus among children below 5 years of age in Nigeria was 23% (CI 95%; 19-27). Regional subgroup analysis showed that the Southern region had a prevalence of 27% (CI 95%; 21-32) while the Northern region had a 20% (CI 95%; 16-25%) prevalence, although the difference was not significant (P = 0.527). Rotavirus was implicated in most cases of acute gastroenteritis with a relative risk of 5.7 (95% CI: 2.9-11.2). The high prevalence and relative risk of rotavirus infections among children in Nigeria shows that rotavirus is an important cause of acute gastroenteritis in Nigeria. Thus, there is a need for further surveillance, especially at community levels together with the introduction of rotavirus vaccines into the national immunization program.

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 rotavirus VP4 and VP7 genetic diversity and detection of GII norovirus in Ibadan as Nigeria introduces rotavirus vaccine

Objective

This cross-sectional study investigated the circulating strains of rotavirus and screened for noravirus in Ibadan, Nigeria as the country introduces the rotavirus vaccine into its national immunization program.

Methods

Sixty-five stool samples were collected from children younger than 5 years with clinically diagnosed diarrhea and screened for the presence of rotavirus and norovirus using RT-PCR. Rotavirus-positive samples were further analyzed to determine the G and P genotypes using semi-nested multiplex PCR.

Results

The rates of rotavirus and norovirus positivity were 30.8% and 10.8%, respectively, whereas the rate of rotavirus and norovirus mixed infection was 4.6%. G1 was the predominant VP7 genotype, followed by G2, G9, and G1G2G9, whereas the predominant VP4 genotype was P[4], followed by P[6], P[8], and P[9]. The mixed P types P[4]P[8] and P[4]P[6] were also detected. G1P[4] was the most common VP4 and VP7 combination, followed by G2P[4], G1[P6], G1P[8], G2P[6], G2P[9], G9P[6], G2G9P[4], G2P[4]P[6], G1P[4]P[8], G2G9P[8], G1G2G9P[8], and G1[non-typable] P[non-typable], which were detected in at least 5% of the samples. Four samples had a combination of non-typable G and P types.

Conclusions

It is essential to monitor the circulation of virus strains prior to and during the implementation of the immunization program.

Suspected Adenovirus Causing an Emerging HEPATITIS among Children below 10 Years: A Review

In October 2021, a case of acute hepatic failure without any known cause was identified in the United States of America. Upon further investigation, other children aged 1-6 years were reported to have the same liver failure, and some of them were positive for adenovirus 41 type F. On 21 April 2022, the Centers for Disease Control and Prevention (CDC) released an alert after 74 cases were identified in United Kingdom (UK) between 5 and 8 April in children below 10 years of age, some of whom were also found to be positive for SARS-CoV-2. All the patients showed symptoms such as vomiting, diarrhea, jaundice, and abdominal pain. The patients' liver enzymes were remarkably increased. A total of 650 cases had been reported from 33 countries as of 27 May 2022, among which 222 cases were reported in the UK alone. No connection with SARS-CoV-2 or its vaccine has been found so far. However, the suspected cause is adenovirus, including its genomic variations, because its pathogenesis and laboratory investigations have been positively linked. Until further evidence emerges, hygiene precautions could be helpful to prevent its spread.

Human Astrovirus in Symptomatic and Asymptomatic Children: A Cross-Sectional Study on Hospitalized and Outpatients from Rural Communities of South Africa between 2017-2021

Human astroviruses are considered acute gastroenteritis agents (AGE) and are largely reported in children worldwide. There are limited data on astrovirus prevalence in rural communities, especially in hospitalized and asymptomatic cases. This study was a cross-sectional survey aiming to investigate the prevalence of classic human astroviruses in symptomatic and asymptomatic cases and hospitalized and outpatient children in rural communities of the Vhembe District, South Africa. A total of 236 stool samples (166 symptomatic and 70 asymptomatic) were collected from young children under 5 years of age. Real-time RT-PCR for astrovirus detection, RT-PCR amplification of capsid and polymerase partial genes as well as Sanger sequencing were performed. The classic astrovirus prevalence in symptomatic patients (7.23%, 12/166) as compared to healthy controls (4.29%, 3/70) was not statistically different (t-value: 1.782, p = 0.141: 95% CI). We did not observe a significant difference of classic astrovirus prevalence rate between the hospitalized group (6.52%, 3/46) and outpatient group (7.5%, 9/120). Symptomatic children below 6 months old were the most affected group (18.18%, 6/33). This study characterized human astrovirus genotype 2 and a putative recombinant strain (polymerase genotype 1/capsid genotype 2). Phylogenetic analysis revealed these genotypes are closely related to the strains circulating elsewhere within the African continent. The findings suggest that astrovirus is a common enteric pathogen in the study area. The results highlight the exposure of children and the need to monitor astroviruses for their potential impact in diarrhoeal diseases.

Pediatric acute gastroenteritis associated with adenovirus 40/41 in low-income and middle-income countries

PURPOSE OF REVIEW

To review the roles of enteric adenovirus types 40 and 41 and nonenteric adenoviruses in the global burden of pediatric diarrhea.

RECENT FINDINGS

Large studies using highly sensitive, type-specific molecular diagnostics have demonstrated a substantial and previously under-estimated burden of pediatric diarrheal disease because of enteric infections with adenovirus types 40/41. However, the true epidemiology of adenovirus 40/41 remains incompletely understood. Similarly, additional adenovirus types may also be implicated as agents of community-acquired pediatric gastroenteritis but current data are too limited to elucidate their epidemiological role(s), if any.

SUMMARY

Efforts at global diarrhea control in low-income and middle-income countries will require combating pediatric gastroenteritis because of enteric adenovirus infections. Future research in these settings using type-specific molecular diagnostics or strain genotyping to fully characterize the epidemiology of adenovirus 40/41 infections, identify non-40/41 adenoviruses significantly associated with gastroenteritis, and develop vaccines effective at preventing adenovirus diarrhea is warranted.

Global prevalence and genotype distribution of norovirus infection in children with gastroenteritis: A meta-analysis on 6 years of research from 2015 to 2020

In the post rotavirus vaccine era, norovirus (NoV) plays an increasingly important role in epidemic and sporadic gastroenteritis among children. This study was designed to provide an updated meta-analytic review of the prevalence of NoV among paediatric patients with gastroenteritis and to clarify the relationship between NoV infection and gastroenteritis. Systematic searches of the literature for potentially relevant studies were carried out from 1 January 2015 to 29 May 2020. The inverse variance method was chosen for weighting of the studies, and the random-effects model was used to analyse data. To determine the association between NoV infection and gastroenteritis in children, pooled odds ratio (OR) and its 95% confidence interval (CI) were computed for case-control studies. The pooled prevalence of NoV infection among 12,0531 children with gastroenteritis from 45 countries across the world was 17.7% (95% CI: 16.3%-19.2%). There were 28 studies with a case-control design, and the pooled prevalence of NoV infection among 11,954 control subjects was 6.7% (95% CI: 5.1%-8.8%). The pooled OR of the association of NoV infection and gastroenteritis was 2.7 (95% CI: 2.2-3.4). The most common NoV genotypes were GII.4 (59.3%) and GII.3 (14.9%). The highest frequency of NoV was found in the age group below 1 year. Our findings indicated a substantial burden of gastroenteritis caused by NoV globally, with GII.4 and GII.3 the major genotypes responsible for the majority of NoV-associated gastroenteritis cases among children. Younger age and male sex can be considered risk factors for NoV-associated gastroenteritis among children.

Genetic Diversity of Enteric Viruses in Children under Five Years Old in Gabon

Enteric viruses are the leading cause of diarrhea in children globally. Identifying viral agents and understanding their genetic diversity could help to develop effective preventive measures. This study aimed to determine the detection rate and genetic diversity of four enteric viruses in Gabonese children aged below five years. Stool samples from children <5 years with (n = 177) and without (n = 67) diarrhea were collected from April 2018 to November 2019. Norovirus, astrovirus, sapovirus, and aichivirus A were identified using PCR techniques followed by sequencing and phylogenetic analyses. At least one viral agent was identified in 23.2% and 14.9% of the symptomatic and asymptomatic participants, respectively. Norovirus (14.7%) and astrovirus (7.3%) were the most prevalent in children with diarrhea, whereas in the healthy group norovirus (9%) followed by the first reported aichivirus A in Gabon (6%) were predominant. The predominant norovirus genogroup was GII, consisting mostly of genotype GII.P31-GII.4 Sydney. Phylogenetic analysis of the 3CD region of the aichivirus A genome revealed the presence of two genotypes (A and C) in the study cohort. Astrovirus and sapovirus showed a high diversity, with five different astrovirus genotypes and four sapovirus genotypes, respectively. Our findings give new insights into the circulation and genetic diversity of enteric viruses in Gabonese children.

Diversity of enteric and non-enteric human adenovirus strains in Brazil, 2006-2011

During 2006-2011, 5035 fecal samples were tested by PCR for human adenovirus (HAdV) and sequenced. HAdV was detected in 198 cases (3.9%), with the highest rate in children ≤ 5 years. Enteric HAdVs were the most prevalent genotypes (78%; 146/187): HAdV-F41 (63.6%; 119/187), HAdV-F40 (12.3%; 23/187), HAdV-A12 (1.6%; 3/187) and HAdV-A31 (0.5%; 1/187). Non-enteric HAdVs were detected in 22% (41/187): HAdV-C1 (8.0%; 15/187), HAdV-C2 (6.9%; 13/187), HAdV-C5 (4.3%; 8/187), HAdV-D8 (1.3%; 2/187), HAdV-B21 (0.5%; 1/187), HAdV-B3 (0.5%; 1/187) and HAdV-C6 (0.5%; 1/187). This 6-year retrospective study points out a high diversity of HAdV types circulating in Brazil and highlights the need to carry out molecular epidemiological studies of HAdV among patients with acute diarrheal infection on a regular basis.

Clinical Signs, Prevention and Treatment of Viral Infections in Infants

Certain infectious diseases are common in infants than any other age groups and are associated with morbidities in childhood and adulthood, and even mortality in severe cases. Environment, epidemic and maternal immunity are the main causes of these infections. Early diagnosis using molecular methods and treatment is therefore important to prevent future complications. Vaccines are recommended during infancy and childhood to prevent these infections. This review highlights some of the most commonly reported viral infections in children, their clinical signs, prevention and treatment.

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.

Molecular epidemiology of astrovirus in children with gastroenteritis in southwestern Nigeria

Human astrovirus (HAstV) is recognized as one of the major causative agents of acute gastroenteritis in children worldwide. Data on the genetic diversity of HAstV in Nigeria are limited. The aim of this study was to determine the prevalence and molecular epidemiology of classical HAstV in children under 5 years of age with acute gastroenteritis in Ogun State, Nigeria. Fecal samples (331) as well as socio-demographic and clinical data were collected across the three senatorial districts of the state from February 2015 to April 2017. One hundred seventy-five samples were randomly selected and analyzed for the presence of HAstV using RT-PCR. PCR amplicons from positive samples were sequenced, and phylogenetic analysis was done to determine genotypes and lineages. The overall prevalence rate was 19.4% (34), with the highest occurrence observed in 2015 (41.4%). Viral coinfections were detected in 13 cases (38.2%). HAstV infection occurred throughout the year and in all age groups, mainly in the age group of 0-12 months. There was significant association between prevalence rate and collection year; however, no association was observed with gender, age, symptoms or risk factors. HAstV-5 was the predominant genotype (76.5%) circulating throughout the study period, followed by HAstV-1 (23.5%), which circulated only in the first 2 years of the study. Phylogenetic analysis showed that all HAstV-5 strains detected belonged to the 5a lineage, while HAstV-1 strains were grouped into lineage 1b. This study, to the best of our knowledge, is the first comprehensive report on molecular characterization of classical HAstV among children with gastroenteritis in the country, and this will serve as baseline information for implementing appropriate infection control practices.

Development and evaluation of a multiplex conventional reverse-transcription polymerase chain reaction assay for detection of common viral pathogens causing acute gastroenteritis

Timely identification of etiological agents of enteric infections is necessary to reduce the burden of infantile diarrheal mortality. Nucleic acid amplification-based detection methods offer a quick, reliable way for diagnosis of microbes in clinical specimens. This study was undertaken to evaluate an easy-to-use, cost-effective multiplex conventional reverse-transcription polymerase chain reaction (RT-PCR) assay developed at the Indian Council of Medical Research-National Institute of Cholera and Enteric Diseases virology laboratory to identify 4 common enteric viruses (rotavirus, norovirus, adenovirus, astrovirus) in stool samples from patients who were being evaluated for acute diarrhea. On comparison with a commercially available real-time PCR method, significant agreement in sensitivity and specificity was observed. Though the turnaround time for RT-PCR was 6-8 h compared to 5-6 h for real-time PCR, the real-time PCR has high test cost (approximately 28 USD/2000 INR) for Fast-Track Diagnostics kit-based quantitative RT-PCR versus 6 USD or 400 INR for conventional multiplex RT-PCR/sample. Thus, the conventional RT-PCR method is expected to be adaptable at local hospitals and health cares in resource-poor settings.

Enteric pathogens associated with gastroenteritis among children under 5 years in sub-Saharan Africa: a systematic review and meta-analysis

Gastroenteritis remains a serious health condition among children under 5 years especially in Africa. We conducted a systematic review and meta-analysis to investigate the aetiologic pathogens of gastroenteritis in the region. We did a systematic search for articles with original data on the aetiology of gastroenteritis and acute diarrhoea among children younger than 5 years. Pooled results were extracted and analysed in STATA version 12.0 using random-effects for statistical test for homogeneity following the guidelines provided in the Cochrane Collaboration and Preferred reporting items for systematic reviews and meta-analyses. Overall, viruses accounted for 50.2% of the cases followed by bacteria with 31.6% of the cases. Parasites accounted for 12.1% of the case. Rotavirus was the most common cause of acute diarrhoea in all regions resulting in 29.2% of the cases followed by E. coli (15.6%) of diarrhoeal cases and Adenovirus (10.8%). The most prevalent parasite detected was Giardia lamblia (7.3%). Acute diarrhoea remains rampant with Rotavirus still being the major pathogen responsible for the disease in children less than 5 years old despite the introduction of vaccine. It is recommended that the vaccine should be promoted much more widely in the region.

Epidemiology and clinical features of rotavirus, adenovirus, and astrovirus infections and coinfections in children with acute gastroenteritis prior to rotavirus vaccine introduction in Meerut, North India

There are limited reports on the etiology of multiple enteric viruses causing acute gastroenteritis (AGE) in North India. In the present study we have determined the prevalence of three enteric viruses, namely rotavirus, astrovirus (AstV) and adenovirus (AdV) in a total of 312 diarrheic children (<5 years) hospitalized at Lala Lajpat Rai Memorial Medical College, Meerut, Uttar Pradesh from August 2014 to July 2016; and results were compared with data from Delhi. The fecal samples were individually screened for group A rotavirus (RVA), AdV, and AstV using enzyme immunoassay kits. At least one viral agent was detected in 29.2% of 312 fecal specimens. RNA of rotavirus antigen-positive samples was extracted by TRIzol method. Rotavirus G/P genotyping was performed using seminested multiplex reverse transcriptase-polymerase chain reaction. RVA was the most predominant virus (18.3%) followed by AstV (12.5%), and AdV (9.9%). Coinfections were detected in 10.6% cases and the most common coinfection in diarrheic children was RVA combined with AstV (36.4%). Overall, the enteric viruses were found most prevalent in the 6 to 11 months age group (P = .01). Increased duration of vomiting (≥3 days) was significantly (P = .04) associated with AdV infection (61.3%) as compared with AstV (30.76%) and rotavirus (26.31%). G1P[8] was detected throughout as the most prevalent rotavirus strain (10.5%). Unusual RV strains like G2P[6] and G2P[8] were also detected. Of note G3, G4, and G12 rotavirus were detected for the first time in Meerut. This is the first report that demonstrated the important contribution of multiple enteric viruses causing AGE in young children in this part of Uttar Pradesh (Meerut).