Rotavirus research: 2014-2020

Liquid-liquid phase separation in viral infection: From the occurrence and function to treatment potentials

Liquid-liquid phase separation (LLPS) of biomacromolecules, as a widespread cellular functional mechanism, is closely related to life processes, and is also commonly present in the lifecycle of viruses. Viral infection often leads to the recombination and redistribution of intracellular components to form biomacromolecule condensates assembled from viral replication-related proteins and intracellular components, which plays an important role in the process of viral infection. In this review, the key and influencing factors of LLPS are generalized, which mainly depend on various molecular interactions and environmental conditions in solution. Meanwhile, some examples of viruses utilizing LLPS are summarized, which are conducive to further understanding the subtle and complex biological regulatory processes between phase condensation and viruses. Finally, some representative antiviral drugs targeting phase separation that have been discovered are also outlined. In conclusion, in-depth study of the role of LLPS in viral infection is helpful to understand the mechanisms of virus-related diseases from a new perspective, and also provide a new therapeutic strategy for future treatments.

Rotaviruses and Rotavirus Vaccines: Special Issue Editorial

Species A rotaviruses (RVA) are a major cause of acute gastroenteritis in infants and young children and in the young of various mammalian and avian species [...].

CRISPR/Cas12 System-Based Assay for Rapid, Sensitive Detection of Rotavirus in Food Samples

Foodborne viruses have become an important threat to food safety and human health. Among the foodborne viruses, group A rotavirus is the most important pathogen of diarrhea in autumn and winter. The field detection of rotavirus is crucial for the early control of infection and patient management. Quantitative real-time reverse transcription-polymerase chain reaction is the most widely used in virus detection. However, the technique relies on high-cost instruments and trained personnel, which limit its use in field detection. In this study, we developed accurate, realizable, and simple detection methods by combining optimized CRISPR (clustered regularly interspaced short palindromic repeats) Cas12 and reverse transcription loop-mediated isothermal amplification (RT-LAMP) (reverse transcription loop-mediated isothermal amplification) to reduce the requirements for temperature control and costly real-time fluorescence polymerase chain reaction instruments. We investigated two nucleic acid detection systems combining RT-LAMP with CRISPR Cas12a and RT-LAMP with CRISPR Cas12b and compared them with reverse transcription-quantitative polymerase chain reaction. The resulting detection system only needs a reaction temperature and in single tube to react for 60 min with the detection sensitivity of 38 copies/μL. Overall, this study developed an innovative method for the rapid detection of rotavirus in food samples, which will help to effectively identify food contaminated by pathogens and prevent human infections and economic losses caused by disease outbreaks.

TLR3/TRIF and MAVS Signaling Is Essential in Regulating Mucosal T Cell Responses during Rotavirus Infection

The functions of the natural dsRNA sensors TLR3 (TRIF) and RIG-I (MAVS) are crucial during viral challenge and have not been accurately clarified in adaptive immune responses to rotavirus (RV) infection. In this study, we found that RV infection caused severe pathological damage to the small intestine of TLR3-/- and TRIF-/- mice. Our data found that dendritic cells from TLR3-/- and TRIF-/- mice had impaired Ag presentation to the RV and attenuated initiation of T cells upon viral infection. These attenuated functions resulted in impaired CD4+ T and CD8+ T function in mice lacking TLR3-TRIF signaling postinfection. Additionally, attenuated proliferative capacity of T cells from TLR3-/- and TRIF-/- mice was observed. Subsequently, we observed a significant reduction in the absolute number of memory T cells in the spleen and mesenteric lymph node (MLN) of TRIF-/- recipient mice following RV infection in a bone marrow chimeric model. Furthermore, there was reduced migration of type 2 classical dendritic cells from the intestine to MLNs after RV infection in TLR3-/- and TRIF-/- mice. Notably, RV infection resulted in attenuated killing of spleen and MLN tissues in TRIF-/- and MAVS-/- mice. Finally, we demonstrated that RV infection promoted apoptosis of CD8+ T cells in TRIF-/- and TLR3-/-MAVS-/- mice. Taken together, our findings highlight an important mechanism of TLR3 signaling through TRIF in mucosal T cell responses to RV and lay the foundation for the development of a novel vaccine.

Chimeric Viruses Enable Study of Antibody Responses to Human Rotaviruses in Mice

The leading cause of gastroenteritis in children under the age of five is rotavirus infection, accounting for 37% of diarrhoeal deaths in infants and young children globally. Oral rotavirus vaccines have been widely incorporated into national immunisation programs, but whilst these vaccines have excellent efficacy in high-income countries, they protect less than 50% of vaccinated individuals in low- and middle-income countries. In order to facilitate the development of improved vaccine strategies, a greater understanding of the immune response to existing vaccines is urgently needed. However, the use of mouse models to study immune responses to human rotavirus strains is currently limited as rotaviruses are highly species-specific and replication of human rotaviruses is minimal in mice. To enable characterisation of immune responses to human rotavirus in mice, we have generated chimeric viruses that combat the issue of rotavirus host range restriction. Using reverse genetics, the rotavirus outer capsid proteins (VP4 and VP7) from either human or murine rotavirus strains were encoded in a murine rotavirus backbone. Neonatal mice were infected with chimeric viruses and monitored daily for development of diarrhoea. Stool samples were collected to quantify viral shedding, and antibody responses were comprehensively evaluated. We demonstrated that chimeric rotaviruses were able to efficiently replicate in mice. Moreover, the chimeric rotavirus containing human rotavirus outer capsid proteins elicited a robust antibody response to human rotavirus antigens, whilst the control chimeric murine rotavirus did not. This chimeric human rotavirus therefore provides a new strategy for studying human-rotavirus-specific immunity to the outer capsid, and could be used to investigate factors causing variability in rotavirus vaccine efficacy. This small animal platform therefore has the potential to test the efficacy of new vaccines and antibody-based therapeutics.

Genotyping and Molecular Characterization of VP6 and NSP4 Genes of Unusual Rotavirus Group A Isolated from Children with Acute Gastroenteritis

Group A rotavirus (RVA), which causes acute gastroenteritis (AGE) in children worldwide, is categorized mainly based on VP7 (genotype G) and VP4 (genotype P) genes. Genotypes that circulate at <1% are considered unusual. Important genes also include VP6 (genotype I) and NSP4 (genotype E). VP6 establishes the group and affects immunogenicity, while NSP4, as an enterotoxin, is responsible for the clinical symptoms. The aim of this study was to genotype the VP6 and NSP4 genes and molecularly characterize the NSP4 and VP6 genes of unusual RVA. Unusual RVA strains extracted from fecal samples of children ≤16 years with AGE were genotyped in VP6 and NSP4 genes with Sanger sequencing. In a 15-year period (2007-2021), 54.8% (34/62) of unusual RVA were successfully I and E genotyped. Three different I and E genotypes were identified; I2 (73.5%, 25/34) and E2 (35.3%, 12/34) were the most common. E3 genotype was detected from 2017 onwards. The uncommon combination of I2-E3 was found in 26.5% (9/34) of the strains and G3-P[9]-I2-E3 remained the most frequent G-P-I-E combination (20.6%, 7/34). Children infected with RVA E2 strains had a statistically higher frequency of dehydration (50%) than those infected with RVA E3 strains (p = 0.019). Multiple substitutions were detected in NSP4, but their functional effect remains unknown. The result indicates the genetic diversity of RVA strains. Continuous surveillance of the RVA based on the whole genome will provide better knowledge of its evolution.

The protective role of prebiotics and probiotics on diarrhea and gut damage in the rotavirus-infected piglets

Rotavirus is one of the pathogenic causes that induce diarrhea in young animals, especially piglets, worldwide. However, nowadays, there is no specific drug available to treat the disease, and the related vaccines have no obvious efficiency in some countries. Via analyzing the pathogenesis of rotavirus, it inducing diarrhea is mainly due to disturb enteric nervous system, destroy gut mucosal integrity, induce intracellular electrolyte imbalance, and impair gut microbiota and immunity. Many studies have already proved that prebiotics and probiotics can mitigate the damage and diarrhea induced by rotavirus infection in hosts. Based on these, the current review summarizes and discusses the effects and mechanisms of prebiotics and probiotics on rotavirus-induced diarrhea in piglets. This information will highlight the basis for the swine production utilization of prebiotics and probiotics in the prevention or treatment of rotavirus infection in the future.

Correlates of immune protection against human rotaviruses: natural infection and vaccination

Species A rotaviruses are the leading viral cause of acute gastroenteritis in children under 5 years of age worldwide. Despite progress in the characterization of the pathogenesis and immunology of rotavirus-induced gastroenteritis, correlates of protection (CoPs) in the course of either natural infection or vaccine-induced immunity are not fully understood. There are numerous factors such as serological responses (IgA and IgG), the presence of maternal antibodies (Abs) in breast milk, changes in the intestinal microbiome, and rotavirus structural and non-structural proteins that contribute to the outcome of the CoP. Indeed, while an intestinal IgA response and its surrogate, the serum IgA level, are suggested as the principal CoPs for oral rotavirus vaccines, the IgG level is more likely to be a CoP for parenteral non-replicating rotavirus vaccines. Integrating clinical and immunological data will be instrumental in improving rotavirus vaccine efficacy, especially in low- and middle-income countries, where vaccine efficacy is significantly lower than in high-income countries. Further knowledge on CoPs against rotavirus disease will be helpful for next-generation vaccine development. Herein, available data and literature on interacting components and proposed CoPs against human rotavirus disease are reviewed, and limitations and gaps in our knowledge in this area are discussed.

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.

Antirotaviral activity of dairy byproducts enriched in fractions from hyperimmune bovine colostrum: the effect of thermal and high hydrostatic pressure treatments

Nowadays, rotaviruses remain a major health burden, especially in developing countries, and strategies complementary to vaccination are needed. In this view, dairy fractions have attracted great scientific interest, due to their high content of bioactive compounds. The objective of this study was to evaluate the antiviral activity of whey and buttermilk enriched in proteins from hyperimmune bovine colostrum (HBC) against rotavirus. The enriched fractions were spray-dried and subsequently tested for their neutralizing activity against the bovine rotavirus WC3 strain in vitro, using differentiated Caco-2/TC7 cells. The highest antirotaviral activity was observed when whey and buttermilk were enriched in purified immunoglobulin G (IgG), showing complete rotavirus neutralization at concentrations of 3 and 6 mg mL-1 for whey and buttermilk, respectively. Additionally, the use of a crude immunoglobulin fraction also gave satisfactory results. The inhibitory activities of all samples significantly decreased after the application of heat, except for the IgG-enriched buttermilk which showed a slight increase of activity following the application of short-time treatments (75 or 85 °C for 20 s). This sample also showed a significant increase of activity (13%) after the application of low-intensity high hydrostatic pressure treatment (400 MPa for 5 min). The maximum loss of bioactivity was observed at 600 MPa for 10 min (31 and 20% for whey- and buttermilk-based formulas, respectively). This study provides relevant information on the potential of whey, buttermilk, and HBC to be part of functional products as complementary strategies to combat rotavirus infections.

Postbiotic Activities of Bifidobacterium adolescentis: Impacts on Viability, Structural Integrity, and Cell Death Markers in Human Intestinal C2BBe1 Cells

Acute diarrheal disease (ADD) caused by rotavirus (RV) contributes significantly to morbidity and mortality in children under five years of age. Currently, there are no specific drugs for the treatment of RV infections. Previously, we reported the anti-rotaviral activity of the protein metabolites derived from Bifidobacterium adolescentis. In this study, our aim was to assess the impact of B. adolescentis-secreted proteins (BaSP), with anti-rotaviral activity on the human intestinal C2BBe1 cell line. We initiated the production of BaSP and subsequently confirmed its anti-rotaviral activity by counting the infectious foci using immunocytochemistry. We then exposed the C2BBe1 cells to various concentrations of BaSP (≤250 µg/mL) for 72 h. Cell viability was assessed using the MTT assay, cell monolayer integrity was monitored through transepithelial electrical resistance (TEER), and cytoskeleton architecture and tight junctions (TJs) were examined using confocal microscopy with F-actin and occludin staining. Finally, we utilized a commercial kit to detect markers of apoptosis and necrosis after 24 h of treatment. The results demonstrated that BaSP does not have adverse effects on C2BBe1 cells. These findings confirm that BaSP inhibits rotavirus infectivity and has the potential to strengthen intestinal defense against viral and bacterial infections via the paracellular route.

Seeing Biomolecular Condensates Through the Lens of Viruses

Phase separation of viral biopolymers is a key factor in the formation of cytoplasmic viral inclusions, known as sites of virus replication and assembly. This review describes the mechanisms and factors that affect phase separation in viral replication and identifies potential areas for future research. Drawing inspiration from studies on cellular RNA-rich condensates, we compare the hierarchical coassembly of ribosomal RNAs and proteins in the nucleolus to the coordinated coassembly of viral RNAs and proteins taking place within viral factories in viruses containing segmented RNA genomes. We highlight the common characteristics of biomolecular condensates in viral replication and how this new understanding is reshaping our views of virus assembly mechanisms. Such studies have the potential to uncover unexplored antiviral strategies targeting these phase-separated states.

Bioactivity of Fucoidan-Rich Extracts from Fucus vesiculosus against Rotavirus and Foodborne Pathogens

Marine algae are sources of bioactive components with defensive properties of great value against microbial infections. This study investigated the bioactivity of extracts from brown algae Fucus vesiculosus against rotavirus, the worldwide leading cause of acute gastroenteritis in infants and young children. Moreover, one of the extracts was tested against four foodborne bacteria: Campylobacter jejuni, Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes, and the non-pathogenic: E. coli K12. In vitro tests using MA104 cells revealed that both whole algae extracts and crude fucoidan precipitates neutralized rotavirus in a dose-responsive manner. The maximum neutralization activity was observed when the rotavirus was incubated with 100 μg mL-1 of the hydrochloric acid-obtained crude fucoidan (91.8%), although crude fucoidan extracted using citric acid also demonstrated high values (89.5%) at the same concentration. Furthermore, molecular weight fractionation of extracts decreased their antirotaviral activity and high molecular weight fractions exhibited higher activity compared to those of lower molecular weight. A seaweed extract with high antirotaviral activity was also found to inhibit the growth of C. jejuni, S. Typhimurium, and L. monocytogenes at a concentration of 0.2 mg mL-1. Overall, this study expands the current knowledge regarding the antimicrobial mechanisms of action of extracts from F. vesiculosus.

Species-Specific N-Glycomes and Methylation Patterns of Oysters Crassostrea gigas and Ostrea edulis and Their Possible Consequences for the Norovirus-HBGA Interaction

Noroviruses, the major cause of acute viral gastroenteritis, are known to bind to histo-blood group antigens (HBGAs), including ABH groups and Lewis-type epitopes, which decorate the surface of erythrocytes and epithelial cells of their host tissues. The biosynthesis of these antigens is controlled by several glycosyltransferases, the distribution and expression of which varies between tissues and individuals. The use of HBGAs as ligands by viruses is not limited to humans, as many animal species, including oysters, which synthesize similar glycan epitopes that act as a gateway for viruses, become vectors for viral infection in humans. Here, we show that different oyster species synthesize a wide range of N-glycans that share histo-blood A-antigens but differ in the expression of other terminal antigens and in their modification by O-methyl groups. In particular, we show that the N-glycans isolated from Crassostrea gigas and Ostrea edulis exhibit exquisite methylation patterns in their terminal N-acetylgalactosamine and fucose residues in terms of position and number, adding another layer of complexity to the post-translational glycosylation modifications of glycoproteins. Furthermore, modeling of the interactions between norovirus capsid proteins and carbohydrate ligands strongly suggests that methylation has the potential to fine-tune the recognition events of oysters by virus particles.

Epidemiological Survey and Risk Factor Analysis of 14 Potential Pathogens in Golden Snub-Nosed Monkeys at Shennongjia National Nature Reserve, China

Golden snub-nosed monkeys (Rhinopithecus roxellanae) belong to Class A, the highest level of endangered primate species. Exploring the infection status of potential pathogens in golden snub-nosed monkeys is important for controlling associated diseases and protecting this species. The objective of this study was to investigate the seroprevalence for a number of potential pathogens and the prevalence of fecal adenovirus and rotavirus. A total of 283 fecal samples were collected from 100 golden snub-nosed monkeys in December 2014, June 2015, and January 2016; 26 blood samples were collected from 26 monkeys in June 2014, June 2015, January 2016 and November 2016 at Shennongjia National Reserve in Hubei, China. The infection of 11 potential viral diseases was examined serologically using an Indirect Enzyme-linked Immunosorbent Assay (iELISA) and Dot Immunobinding Assays (DIA), while the whole blood IFN-γ in vitro release assay was used to test tuberculosis (TB). In addition, fecal Adenovirus and Rotavirus were detected using Polymerase Chain Reaction (PCR). As a result, the Macacine herpesvirus-1 (MaHV-1), Golden snub-nosed monkey cytomegalovirus (GsmCMV), Simian foamy virus (SFV) and Hepatitis A virus (HAV) were detected with the seroprevalence of 57.7% (95% CI: 36.9, 76.6), 38.5% (95% CI: 20.2, 59.4), 26.9% (95% CI: 11.6, 47.8), and 7.7% (95% CI: 0.0, 84.2), respectively. Two fecal samples tested positive for Adenovirus (ADV) by PCR, with a prevalence of 0.7% (95% CI: 0.2, 2.5), and further, the amplification products were sequenced. Phylogenetic analysis revealed that they belonged to the HADV-G group. However, other pathogens, such as Coxsackievirus (CV), Measles virus (MeV), Rotavirus (RV), Simian immunodeficiency virus (SIV), Simian type D retroviruses (SRV), Simian-T-cell lymphotropic virus type 1 (STLV-1), Simian varicella virus (SVV), Simian virus 40 (SV40) and Mycobacterium tuberculosis complex (TB) were negative in all samples. In addition, a risk factor analysis indicated that the seroprevalence of MaHV-1 infection was significantly associated with old age (≥4 years). These results have important implications for understanding the health status and conservation of the endangered golden snub-nosed monkey population at Shennongjia Nature Reserve.

Principles of RNA recruitment to viral ribonucleoprotein condensates in a segmented dsRNA virus

Rotaviruses transcribe 11 distinct RNAs that must be co-packaged prior to their replication to make an infectious virion. During infection, nontranslating rotavirus transcripts accumulate in cytoplasmic protein-RNA granules known as viroplasms that support segmented genome assembly and replication via a poorly understood mechanism. Here, we analysed the RV transcriptome by combining DNA-barcoded smFISH of rotavirus-infected cells. Rotavirus RNA stoichiometry in viroplasms appears to be distinct from the cytoplasmic transcript distribution, with the largest transcript being the most enriched in viroplasms, suggesting a selective RNA enrichment mechanism. While all 11 types of transcripts accumulate in viroplasms, their stoichiometry significantly varied between individual viroplasms. Accumulation of transcripts requires the presence of 3' untranslated terminal regions and viroplasmic localisation of the viral polymerase VP1, consistent with the observed lack of polyadenylated transcripts in viroplasms. Our observations reveal similarities between viroplasms and other cytoplasmic RNP granules and identify viroplasmic proteins as drivers of viral RNA assembly during viroplasm formation.

Global Infection Rate of Rotavirus C during 1980-2022 and Analysis of Critical Factors in the Host Range Restriction of Virus VP4

Information on rotavirus C (RVC) infection is lacking, partly because the prevalence of RVC among humans and animals worldwide is undefined. Data on the characteristics of the P genotype among RVC strains are also required. We performed systematic searches on the infection rates of RVC since 1980 based on the literature and gene sequences of the PubMed and GenBank databases. A phylogenetic tree of VP4 genes was constructed to evaluate the distribution of the P genotype of RVC from various hosts. The specific mutation motifs in VP8* with P [2]/P [4]/P [5] specificity were analyzed to elucidate their roles in host range restriction. The rate of RVC infection in humans has fallen from 3% before 2009 to 1%, whereas in animals it has risen from 10% to 25%. The P genotype of RVC showed strict host species specificity, and current human RVC infections are exclusively caused by genotype P [2]. In the VP8* hemagglutinin domain of the P [4]/P [5] genotype of swine RVC, specific insertion or deletion were found relative to the human P [2] genotype, and these motifs are a possible critical factor for host range restriction. Our findings highlight the need for further epidemiological surveillance, preventive strategies, and elucidation of the factors involved in the specific host range restriction of RVC-circulating strains.

Detection and Molecular Characterization of Rotavirus Infections in Children and Adults with Gastroenteritis from Vojvodina, Serbia

Rotaviruses (RV) are the leading cause of gastroenteritis in infants, young children, and adults, responsible for serious disease burden. In the period 2012-2018, a cross-sectional study was conducted using stool samples collected from patients with acute gastroenteritis from Vojvodina, Serbia. We described age and gender distribution, as well as seasonal patterns of RV prevalence. Out of 1853 included stool samples, RV was detected in 29%. Hospitalized children between 1-2 years old were especially affected by RV infection (45%). The highest prevalence of infection was observed during the colder, winter/spring months. We compared sequenced representative G and P genotypes circulating in Serbia with vaccine strains and determined their genetic similarity. Genotype combination G2P[4] was the most prevalent (34.6%), followed by G2P[8] (24.1%) and G1P[8] (21.1%). Given that several epitopes were conserved, neutralization motifs among circulating strains can be characterized as sufficiently matching vaccine strains Rotarix™ and RotaTeq™, but existing antigenic disparities should not be overlooked. The present results contribute to a better insight into the prevalence of rotavirus infection in our region and point out the need for epidemiological surveillance of rotaviruses before the introduction of vaccines. These data can help formulate future vaccine strategies in Serbia.

Prevalence and genotypes distribution of group A rotavirus among outpatient children under 5 years with acute diarrhea in Shanghai, China, 2012-2018

Background

Group A rotavirus (RVA) remains the main causative agent of acute diarrhea among children under five years in countries that have not yet introduced the RVA vaccine worldwide. Long-term and continuous monitoring data on RVA infection in outpatient children were lacking in Shanghai. We investigated the prevalence and distribution of RVA genotypes in outpatient children with acute diarrhea in Shanghai from 2012 to 2018.

Methods

Stool specimens of outpatient children under five years were collected from the Children’s Hospital of Fudan University in Shanghai, China. All the samples enrolled in this study were detected and characterized for the P and G genotypes of RVA were determined using the semi-multiplex RT-PCR technique.

Results

Of 1814 children enrolled with acute diarrhea and having specimens collected, 246 (13.6%) were infected with RVA. The highest frequency of RVA was observed in children younger than two years old (87.0%, 214/246). Year-round RVA transmission was observed and the RVA detection rate peaked every winter and troughed in summer. In this study, 12 different RVA strains were identified in children. G9P[8] (49.2%, 121/246) was detected as the most prevalent genotype, followed by G–P[8] (22.8%, 56/246), G3P[8] (11.4%, 28/246), and G9P- (4.9%, 12/246). Although RVA strains detected in this study varied with the time, G9P[8] has been the most predominant circulating genotype since 2012. Furthermore, 12.2% (30/246) RVA positive samples were co-infected with other diarrhea viruses.

Conclusion

The present analysis showed that RVA was still a major cause of children with acute diarrhea in Shanghai from 2012 to 2018. A great diversity of RVA strains circulated in children with acute diarrhea with G9P[8] being the predominant genotype since 2012. Long-term and continuous monitoring of RVA genotypes is therefore indispensable to refine future vaccine strategy in Shanghai.