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Viruses remain the leading cause of acute gastroenteritis (AGE) worldwide. Recently, we reported the abundance of AGE viruses in raw sewage water (SW) during the COVID-19 pandemic, when viral AGE patients decreased dramatically in clinics. Since clinical samples were not reflecting the actual state, it remained important to determine the circulating strains in the SW for preparedness against impending outbreaks. Raw SW was collected from a sewage treatment plant in Japan from August 2018 to March 2022, concentrated by polyethylene-glycol-precipitation method, and investigated for major gastroenteritis viruses by RT-PCR. Genotypes and evolutionary relationships were evaluated through sequence-based analyses. Major AGE viruses like rotavirus A (RVA), norovirus (NoV) GI and GII, and astrovirus (AstV) increased sharply (10-20%) in SW during the COVID-19 pandemic, though some AGE viruses like sapovirus (SV), adenovirus (AdV), and enterovirus (EV) decreased slightly (3-10%). The prevalence remained top in the winter. Importantly, several strains, including G1 and G3 of RVA, GI.1 and GII.2 of NoV, GI.1 of SV, MLB1 of AstV, and F41 of AdV, either emerged or increased amid the pandemic, suggesting that the normal phenomenon of genotype changing remained active over this time. This study crucially presents the molecular characteristics of circulating AGE viruses, explaining the importance of SW investigation during the pandemic when a clinical investigation may not produce the complete scenario.

Background: Viral enteric infections are illnesses caused by several types of viruses that primarily affect the gastrointestinal system. Globally, three major viruses associated with gastroenteritis, including norovirus (NoV), rotavirus A (RVA), and human adenovirus (HAdV), have been widely recognized. Accordingly, a rapid and sensitive diagnostic tool, such as immunochromatographic (IC) test, for diarrheal virus detection is required and helpful for rapid diagnosis. Methods: The IP-Triple I IC test kit for simultaneous triple virus detections of NoV, RVA, and HAdV was evaluated for its efficacy by using stool specimens that were known positive for these viruses by real-time RT-PCR or PCR, which was used as the gold standard method. Results: The results revealed that the IP-Triple I IC test kit exhibited a very high level of specificity (100%) for NoV, RVA, and HAdV detections, while the sensitivity was slightly different for these three viruses. The sensitivity of detection for RVA was 86.7%, whereas those for NoV and HAdV were 70.6% and 76.2%, respectively. This IPTriple I IC kit could detect common antigens of a wide range of NoV, RVA, and HAdV genotypes (NoV GII.2, GII.4, GII.6, GII.7, GII.10, GII.17, RVA G1P[8], G2P[4], G3P[8], G8P[8], G9P[8], HAdV-C1, -C2, -C5, -A12, -F40, and -F41). Conclusions: Our results revealed that the IP-Triple I IC test kit is highly effective for simultaneous, direct detection of common antigens of several genotypes of NoV, RVA, and HAdV in stool specimens and useful for screening and rapid diagnosis of diarrheal viruses during the seasonal outbreak. [ABSTRACT FROM AUTHOR]

Rotavirus A (RVA) is the main cause of acute gastroenteritis among children under the age of five globally. The unusual bat‐like human RVA strains G3P[10] (RVA/Human‐wt/THA/CMH079/05/2005/G3P[10] and RVA/Human‐wt/THA/CMH‐S015‐19/2019/G3P[10]) were detected in children with acute gastroenteritis in 2005 and 2019, respectively, in the same geographical area of Northern Thailand. To elucidate the genetic backgrounds of these unusual or bat‐like human RVA strains, the complete genome of these RVA strains was sequenced and phylogenetically analyzed. All eleven genome segments of these G3P[10] strains were genotyped as G3‐P[10]‐I8‐R3‐C3‐M3‐A9‐N3‐T3‐E3‐H6, which is closely related to bat G3P[10] RVA strain (RVA/Bat‐tc/CHN/MYAS33/2013/G3P[10]) and bat‐like human RVA strain (RVA/Human‐wt/THA/MS2015‐1‐0001/2015/G3P[10]). The findings indicate that human G3P[10] RVA strains detected in this study (RVA/Human‐wt/THA/CMH079/05/2005/G3P[10] and RVA/Human‐wt/THA/CMH‐S015‐19/2019/G3P[10]) contained all eleven genome segments similar to those of bat RVA strains and appeared to be human RVA strains of bat origin. Phylogenetic analysis revealed that several genome segments of these two RVA strains were also closely related with those of other species in addition to bats and had a zoonotic transmission history. The results of this study supported the roles of interspecies transmission of RVA strains among bats and humans in the natural environment and provided convincing evidence that the evolution of human RVAs was closely interrelated with those of animal RVAs. Continuing surveillance of RVAs in humans and animals is imperative to gain a better understanding of the origin and the evolution of these viruses. [ABSTRACT FROM AUTHOR]

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

Introduction: Enteroviruses (EVs) are recognized as potential causative agents of acute gastroenteritis (AGE) in children worldwide. This study aimed to investigate the epidemiology and molecular characteristics of EV infection in children admitted to hospitals with AGE in Chiang Mai, Thailand from 2019 to 2022. Methods: A total of 1,148 fecal samples collected from patients with AGE were screened for the presence of EV using RT-PCR. The prevalence, co-infection with common diarrheal viruses, and seasonal pattern of EV were examined. The genotypes of EV were identified based on the VP1 sequence and phylogenetic analysis. Results: The overall prevalence of EV in AGE patients was 8.8% (101/1,148). After the COVID-19 outbreak in 2019, a significant decrease in the EV infection rate and genotype diversity was observed (p < 0.05). EV infection alone was observed in 68.3% (69/101) of cases while co-infection with other enteric viruses was 31.7% (32/101). The seasonal pattern of EV infection showed a peak prevalence during the rainy season. EV species A was the most prevalent (37.5%), followed by species B (32.3%), species C (29.2%), and species D (1.0%). Twenty-five genotypes of EV were identified with the most predominant of the coxsackievirus A2 (CVA2) (13.5%), CV-B2 (7.3%) and CV-A24 (5.2%). Conclusion: Our data demonstrate a significant decrease in the prevalence and diversity of EV circulating in AGE patients during the COVID-19 pandemic and highlight the emergence of CV-A2 during this study period. These findings contribute to a better understanding of the molecular epidemiology and diversity of EV in patients with AGE and provide useful information for further investigation into the potential association between specific EV genotypes and AGE in future studies. [ABSTRACT FROM AUTHOR]