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Despite global rotavirus vaccination efforts, rotavirus remains a leading cause of childhood deaths from acute gastroenteritis. Post-vaccination studies in India, particularly in eastern India, have been limited, despite high prevalence of rotavirus in this region prior to vaccine introduction. This study was conducted to assess the impact of rotavirus vaccine on the epidemiology of rotavirus and other enteric viruses, as well as the changes in the diversity of rotavirus strains among children (≤5 years) with acute gastroenteritis. A total of 877 stool samples from children hospitalized with acute diarrhea during 2022–2023, were screened for enteric viruses using multiplex PCR. Rotavirus positive samples were genotyped by sequencing and phylogenetic analysis of VP4 and VP7 genes were done. Out of 877 diarrheal cases, 47 % tested positive for at least one enteropathogenic virus. Rotavirus was most prevalent (25.9 %), followed by norovirus (11.4 %), adenovirus-F (10.6 %), and astrovirus (5.3 %). Among mixed infections, rotavirus and norovirus co-infections were the most common. Rotavirus infection was highest in children aged 12–24 months, while other enteric viruses were more common in the 6–24 month age group. Clinical severity was higher among rotavirus-infected patients compared to those infected with other enteric viruses. The G3P[8] genotype of rotavirus predominated, with notable increase in G2P[4] and the detection of rare strains like G3P[6] and G11P[25]. G3P[6] was identified for the first time in this region showing Wa-like genome constellation. Unlike pre-vaccine period, G9 genotype was not detected. Mutations in antigenic epitope of circulating strains compared to vaccine strains may affect vaccine efficacy. The study highlights the persistent burden of childhood diarrhea despite rotavirus vaccination. Subtle alterations in the proportion of other enteric viruses and diversity of circulating rotavirus genotypes in the post-vaccination period were observed. Continuous long-term surveillance is required to evaluate the impact of vaccine in this region. • RV remains predominant cause of childhood gastroenteritis after introduction of RV vaccine. • NoV was the second major enteric virus after RV followed by HAdV-F and AstV. • G3P[8] continues to be dominant genotype, followed by G2P[4]. There is notable absence of G9 genotype. • Clinical severity remains high in RV infected cases compared to other enteric viruses. • Detection of a rare G3P[6] strain for the first time in eastern India. [ABSTRACT FROM AUTHOR]

Norovirus (NoV) is one of the major causes of acute viral gastroenteritis in humans. Genetic variation is abundant, and prevalent genotypes vary from year to year and region to region. Since NoVs are difficult to amplify in cultured cells, genome RNA-free virus-like particles (VLPs) that mimic the capsid structure of the virus are promising vaccine candidates for the prevention of NoVs infection, and the development of multivalent VLP vaccines is required to prevent NoV infection in a wide range of genotypes. In this study, we attempted to produce NoV VLPs of the top nine genotypes that have a history of epidemics in Japan using the silkworm-baculovirus expression vector system (silkworm-BEVS), which has a proven track record in the mass production of recombinant proteins. In silkworm pupae infected with recombinant baculoviruses constructed to express VP1s, the major protein that forms VLP, the NoV VP1 protein was expressed in large amounts. Most genotypes of VP1 accumulated in the cytoplasm as soluble proteins, but solubility was reduced for that of two genotypes. VP1s of five genotypes could be purified in large quantities (>0.9 mg per pupa) by a two-step purification process, and gel filtration chromatography analysis confirmed the formation of VLPs. This study demonstrates the utility of silkworm-BEVS in producing NoV VLPs of multiple genotypes and provides the basis for the development of a multivalent vaccine against genetically diverse NoV infections. • The silkworm-baculovirus expression system was used to express nine endemic norovirus VP1s. • Most of the expressed VP1s were soluble and formed VLPs. • VP1 of five genotypes of the GII genogroup could be purified to more than 0.9 mg per pupa. • GI genogroup was less soluble and heterogeneous in particle formation compared to GII genogroup. [ABSTRACT FROM AUTHOR]

Acute gastroenteritis is a major health concern for all age groups and accounts for more than 2.5 million deaths annually in children under five years old. Human Aichi virus causes acute gastroenteritis and is associated with foodborne outbreaks. Little is known about its pathogenicity, evolution, and geographical distribution. This study aimed to describe the global seroprevalence of AiV-1 and its genotype distribution, track outbreaks, and estimate co-infection rates with other viral gastroenteritis. A comprehensive systematic search of the epidemiological aspects of AiV-1 was conducted using peer-reviewed English original articles indexed in several scientific database libraries since its first detection in Japan until October 2022. A total of 55 published studies were included in the final analysis based on the inclusion criteria. The global prevalence of AiV-1 was 1.45 %. To date, nine AiV-1 outbreaks were reported following the first oyster-associated outbreak in Japan between 1987 and 1991. AiV-1 genotype A has a worldwide distribution, whereas genotypes B and C have a pattern of geo-localization. The gradual and significant increase of AiV-1 seroprevalence with age was reported in all studies. The most predominant viruses causing viral coinfection among AiV-1-infected patients were Norovirus (36.55 %), Rotavirus (18.91 %), and Sapovirus (15.13 %). Coinfections with Norovirus (p-value 0.003), Rotavirus (p = 0.007), and Human Astrovirus (p = 0.032) were significantly correlated with AiV-1 coinfection. This was the first comprehensive systematic review of AiV-1. Although AiV-1 has a low global prevalence, it can be considered a health concern due to its association with childhood gastroenteritis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electroanalytical method for nitazoxanide sensing in water and pharmaceutical samples. • Nitazoxanide determination in the absence of complex modification of electrode. • Good analytical performance ranging of 2.0–20.0 µmol L−1 of NTZ, LOD = 0.57 µmol L−1. • Selectivity even in the presence of other drugs also used in the COVID-19 pandemic. • All analysis were performed in small sample volumes for low waste generation. Consumption of Nitazoxanide (NTZ), a compound belonging to the class of nitrothiazoles, has increased due to its efficiency in treating viral gastroenteritis caused by rotavirus and norovirus "coronavirus disease". Thus, developing a method capable of monitoring NTZ in wastewater and pharmaceutical formulations is relevant to human health control. However, most methods for NTZ determination are expensive and time-consuming. Hence, we present a fast, efficient, and low-waste method for NTZ monitoring in drugs and water samples using a boron-doped diamond electrode. A 3D-printed electrochemical cell with a capacity of 2 mL was used for all studies. Besides the simplicity of low waste generation, the method provided good analytical performance with a linear range of 2.0–20.0 µmol L−1 of NTZ, and a limit of detection (LOD) of 0.57 µmol L−1. Recovery percentages between 99 and 107 % were obtained to analyze spiked samples. In addition, we demonstrate that the LOD value can be significantly improved by 50 times after applying a pre-concentration step using solid-phase extraction. Therefore, we believe the described approach is a simple and efficient electrochemical method for monitoring NTZ levels in pharmaceutical and environmental samples without laborious sample preparation procedures. This is the first report to describe the use of BDD electrodes for NTZ monitoring and environmental sample analysis using an eco-friendly approach. [ABSTRACT FROM AUTHOR]

Rapid and accurate diagnostic methods are crucial for managing viral gastroenteritis in children, a leading cause of global childhood morbidity and mortality. This study introduces a novel microfluidic-Flap endonuclease 1 (FEN1)-assisted isothermal amplification (MFIA) method for simultaneously detecting major viral pathogens associated with childhood diarrhea—rotavirus, norovirus, and adenovirus. Leveraging the specificity-enhancing properties of FEN1 with a universal dspacer-modified flap probe and the adaptability of microfluidic technology, MFIA demonstrated an exceptional detection limit (5 copies/μL) and specificity in the simultaneous detection of common diarrhea pathogens in clinical samples. Our approach addresses the limitations of current diagnostic techniques by offering a rapid (turn around time <1 h), cost-effective, easy design steps (universal flap design), and excellent detection performance method suitable for multiple applications. The validation of MFIA against the gold-standard PCR method using 150 actual clinical samples showed no statistical difference in the detection performance of the two methods, positioning it as a potential detection tool in pediatric diagnostic virology and public health surveillance. In conclusion, the MFIA method promises to transform pediatric infectious disease diagnostics and contribute significantly to global health efforts combating viral gastroenteritis. [ABSTRACT FROM AUTHOR]

Viral gastroenteritis is commonly reported in dogs and involves a great diversity of enteric viruses. In this research, viral diversity was investigated in dogs with diarrhea in Northern Brazil using shotgun metagenomics. Furthermore, the presence of norovirus (NoV) was investigated in 282 stool/rectal swabs of young/adult dogs with or without diarrhea from two public kennels, based on one-step reverse transcription polymerase chain reaction (RT-PCR) for genogroup VI and VII (GVI and GVII) and real-time RT-PCR for GI, GII, and GIV. Thirty-one viral families were identified, including bacteriophages. Phylogenetic analyses showed twelve complete or nearly complete genomes belonging to the species of Protoparvovirus carnivoran1 , Mamastrovirus 5 , Aichivirus A2 , Alphacoronavirus 1, and Chipapillomavirus 1. This is the first description of the intestinal virome of dogs in Northern Brazil and the first detection of canine norovirus GVII in the country. These results are important for helping to understand the viral groups that circulate in the canine population. • Fecal samples from dogs with or without enteric signs were screened for norovirus. • First detected canine norovirus genogroup VII in fecal samples from Latin America. • The first description of the intestinal viroma of urban dogs in Northern Brazil. • Analysis of viral diversity had shown 31 viral families in cases of canine diarrhea. • The complete or nearly complete genome sequences were determined for twelve strains. [ABSTRACT FROM AUTHOR]

• High vaccine coverage rotavirus (RV) national immunization program (NIP) started in Finland in 2009. • Immediate and long-term impact of rotavirus vaccination in children. • Incidence of rotavirus gastroenteritis remained low in RV NIP eligible children up to 7 years of age. • Differences in RVGE incidence were observed in municipalities with optimal versus suboptimal VCR. Rotavirus (RV) vaccination was included in the Finnish National immunization Program (NIP) in 2009. RotaTeq (RV5) has been used exclusively with a national average vaccination coverage rate (VCR) of > 90%. While previous studies have demonstrated that inpatient rotavirus gastroenteritis (RVGE) admissions declined by as much as 96% in Finnish children ≤ 5 years old following RV vaccination introduction, no study has evaluated long-term protection after vaccination in Finland. In this study, we analyze incidence of hospital outpatient visits and inpatient admissions of gastroenteritis in children up to 7 years of age. We first describe the incidence of RVGE, viral gastroenteritis (VGE), and acute gastroenteritis (AGE) for all Finnish children born during 2008–2011. Children were stratified by the year of birth into not-eligible, partially eligible and rotavirus vaccine-eligible (born in 2008, 2009, 2010 and 2011, respectively). Hospital inpatient and outpatient data was collected from the National Care Register for all children from birth until December 31st, 2018. We also studied RVGE incidence during 2014–2017 for children<3 years of age in municipalities with VCRs of 90% and above and municipalities with VCRs below 90%. RVGE incidence decreased significantly soon after implementation of RV vaccination in the NIP. In vaccine-eligible cohorts, no clear peak incidence in the youngest age groups could be observed, and no RVGE cases were observed beyond 6 years after vaccination, in contrast to vaccine ineligible and partially eligible cohorts. Despite an overall high VCR in Finland, regions with high VCR had lower incidence of RVGE than regions with lower VCR. Incidence of RVGE has remained low in all age groups during the 10 years following introduction of RV vaccine in the Finnish NIP. Differences in RVGE incidence were observed in regions with high as compared with lower VCR, highlighting the importance of maintaining high vaccination coverage. [ABSTRACT FROM AUTHOR]

• This was the fourth follow-up study examining rotavirus, norovirus, and sapovirus. • Overall, 175 children (98% of those eligible) had complete clinical data available. • Rotavirus returned as the most detected pathogen, as detections increased by 40%. • Rotavirus vaccine-induced protection remains for years after vaccination. • The all-cause incidence of acute gastroenteritis has decreased by 88% from pre-vaccination seasons. This study was performed to assess the prevalence and circulating genotypes of rotavirus, norovirus, and sapovirus in children. The results were compared to those of previous surveillance studies covering the years 2006–2008, 2009–2011, and 2012–2014 with similar methodology and setting, encompassing the start of universal vaccination with RotaTeq in 2009. Stool samples were collected from children aged <16 years with acute gastroenteritis at Tampere University Hospital, Finland, from January 1, 2017 to December 31, 2018. The samples were analysed using reverse transcription PCR and positive amplicons were sequenced. A total of 178 stool samples were collected from 214 children. Rotavirus was detected in 56 (32%) stool samples, norovirus in 48 (27%), and sapovirus in 11 (6.3%). Rotavirus G9P[8] and G12P[8] were the most detected genotypes in vaccinated and unvaccinated children. GII.4 comprised 96% of the norovirus detections. The prevalence of all-cause acute gastroenteritis in a hospital setting decreased by 51% compared to 2012–2014, and by 88% compared to 2006–2008. Rotavirus returned as the most common cause of viral acute gastroenteritis in children, but the prevalence remains at a low level. No considerable changes were seen in the genotyping results of norovirus and sapovirus. [ABSTRACT FROM AUTHOR]

• We conducted the longest study on the trends of enteric virus in Korea, and the positivity rate was in the order of norovirus (9.9 %), rotavirus (6.7 %), adenovirus (3.3 %), astrovirus (1.4 %), and sapovirus (0.6 %). • We are the first to describe how non-pharmaceutical interventions influence the trends of enteric viruses during and after pandemic periods, using a machine learning model. • The bayesian structural time series model revealed that intervention negatively affected the detection of viruses by -73.0 % to -91.0 %, with rotavirus being the least affected. • Non-pharmaceutical intervention mitigation positively affected the detection of all viruses, ranging from 79.0 % to 200.0 %, except for rotavirus. Viral gastroenteritis continues to be a leading cause of death in low-income countries. The impact of nonpharmaceutical interventions (NPIs) on the transmission of gastroenteritis-causing viruses during the COVID-19 pandemic is understudied. To investigate the 10-year trends of enteric viruses and estimate the impact of implementing and mitigating NPIs. Data regarding norovirus, rotavirus, adenovirus, astrovirus, and sapovirus detection were collected from five Korean hospitals between January 2013 and April 2023. We compared positivity between the pre-pandemic, pandemic, and post-pandemic periods. The causal effects of implementing and mitigating NPIs were quantified using the Bayesian Structural Time Series (BSTS) model. Norovirus was most frequently detected (9.9 %), followed by rotavirus (6.7 %), adenovirus (3.3 %), astrovirus (1.4 %), and sapovirus (0.6 %). During the pandemic, the positivity of all five viruses decreased, ranging from -1.0 % to -8.1 %, with rotavirus showing the greatest decrease. In the post-pandemic period, positivity rebounded for all viruses except for rotavirus. The BSTS model revealed that NPI implementation negatively affected the detection of all five viruses, resulting in reductions ranging from -73.0 % to -91.0 % compared to the prediction, with rotavirus being the least affected. Conversely, NPI mitigation positively affected the detection of all viruses, ranging from 79.0 % to 200.0 %, except for rotavirus. Trends observed over 10 years show that NPIs have had a major impact on changes in enteric virus detection. The effect of vaccines, in addition to NPIs, on rotavirus detection requires further investigation. Our findings emphasize the importance of NPIs in infection control and prevention. [ABSTRACT FROM AUTHOR]

The introduction of the rotavirus vaccine in 2006 significantly reduced childhood incidence of acute gastroenteritis (AGE) worldwide. The rotavirus vaccine was included in Poland's national immunization program in 2021. Our study aimed to summarize the epidemiology of AGE in northeastern Poland prior to 2021 and to evaluate the effectiveness of voluntary, out-of-pocket rotavirus childhood vaccination on the incidence of rotavirus AGE. A review of patients aged 0–17 years with gastroenteritis hospitalized between 2006 and 2020 in northeastern Poland in the context of rotavirus vaccine coverage in the region. Rotavirus was the most common agent of gastroenteritis in hospitalized patients. The seasonality of rotavirus gastroenteritis peaked between February and May in each year of study, except for 2020, when the COVID-19 pandemic skewed any viable comparison of seasonality. Rotavirus vaccine coverage in northeastern Poland did not exceed 25% during the study period and had no impact on hospitalization numbers. Rotavirus was the primary causative agent of AGE in children hospitalized in northeastern Poland during the study period. Voluntary vaccinations did not affect the number of hospitalizations due to rotavirus AGE. Our data suggest that universal immunization is key to achieving a significant reduction of rotavirus-associated diarrhea. [ABSTRACT FROM AUTHOR]

Background/purpose: The FUT2 gene is a histo-blood group antigen (HBGA) that determines the susceptibility to Norovirus (NoV) infection. This study investigated the clinical significance of the FUT2 gene profile and HBGA expression in NoV infection.Methods: Fecal specimens were collected from children in Chang-Gung Children's Hospital with acute gastroenteritis (AGE). The medical records were reviewed for clinical data. The viral etiology of gastroenteritis was validated using molecular methods. Genomic DNA was isolated from saliva or whole blood with the Puregene B Kit, according to the manufacturers' instructions. Single-nucleotide polymorphisms (SNPs) were determined by real-time PCR assays.Results: FUT2 gene DNA was examined in 98 children with AGE. NoV was detected by RT-PCR in 44 patients (44.8%), while 54 (55.2%) had non-NoV AGE. Of the 44 NoV patients, 38 (86.3%) were secretors (no G428A mutation) and six (13.7%) were non-secretors (G428A mutation). Of the 54 non-NoV AGE patients, 28 (51.9%) were secretors and 20 (48.1%) were non-secretors. NoV-infected patients who were secretors had more frequent vomiting (P < 0.001), longer duration of diarrhea (P < 0.001), and greater overall disease severity score (P < 0.001) compared with non-secretors. Non-NoV infection secretor AGE patients had a longer duration of diarrhea (P < 0.001) than non-secretors.Conclusion: FUT2 secretor status affects NoV AGE in children. Secretor patients have prolonged diarrhea, more frequent vomiting, more severe disease, and greater infection transmissibility than non-secretors. [ABSTRACT FROM AUTHOR]

Noroviruses are the main causative agents of acute viral gastroenteritis, but the host factors that restrict their replication remain poorly identified. Guanylate-binding proteins (GBPs) are interferon (IFN)-inducible GTPases that exert broad antiviral activity and are important mediators of host defenses against viral infections. Here, we show that both IFN-α stimulation and murine norovirus (MNV) infection induce GBP2 expression in murine macrophages. Results from loss- and gain-of-function assays indicated that GBP2 is important for IFN-α-dependent anti-MNV activity in murine macrophages. Ectopic expression of MNV receptor (CD300lf) in human HEK293T epithelial cells conferred susceptibility to MNV infection. Importantly, GBP2 potently inhibited MNV in these human epithelial cells. Results from mechanistic dissection experiments revealed that the N-terminal G domain of GBP2 mediates these anti-MNV effects. R48A and K51A substitutions in GBP2, associated with loss of GBP2 GTPase activity, attenuated the anti-MNV effects of GBP2. Finally, we found that nonstructural protein 7 (NS7) of MNV co-localizes with GBP2 and antagonizes the anti-MNV activity of GBP2. These findings reveal that GBP2 is an important mediator of host defenses against murine norovirus. [ABSTRACT FROM AUTHOR]

• Overall, 10% of acute gastroenteritis cases were caused by astrovirus. • The mean age of cases positive for astrovirus was 12.41 ± 6.21 months. • Infection with astrovirus was higher in the dry season. • Higher socio-economic status was found to be associated with protection against infection. Acute viral gastroenteritis is a major public health concern, especially among children younger than 5 years of age. The aim of this study was to determine the occurrence of human astrovirus infection in children with acute gastroenteritis. Stool specimens were collected from 506 children under 5 years of age hospitalized with acute diarrhoea (289 male and 208 female), and human astrovirus was investigated by RT-PCR. Associations of socio-demographic, clinical, and behavioural conditions with infection were analysed. The overall prevalence of human astrovirus was found to be 10.3%. The mean age of positive cases was 12.41 ± 6.21 months and this was associated with infection (p = 0.013). Children >18 months of age were at three times the risk of infection when compared to those aged 0–6 months (odds ratio (OR) 3.19, 95% confidence interval (CI) 1.15–8.88; p = 0.026). Children living in houses with more than one room (OR 0.60, 95% CI 0.28–0.96; p = 0.036) and mothers using treated water (OR 0.47, 95% CI 0.25–0.86; p = 0.015) were associated with reduced infection. In this study, infection with astrovirus was common in acute gastroenteritis cases among children younger than 5 years of age. Drinking treated water and living in non-crowded environments protected the children from infection. [ABSTRACT FROM AUTHOR]

Human norovirus (HuNoV) and human rotavirus (HRV) are the leading causes of gastrointestinal diarrhea. There are no approved antivirals and rotavirus vaccines are insufficient to cease HRV associated mortality. Furthermore, treatment of chronically infected immunocompromised patients is limited to off-label compassionate use of repurposed antivirals with limited efficacy, highlighting the urgent need of potent and specific antivirals for HuNoV and HRV. Recently, a major breakthrough in the in vitro cultivation of HuNoV and HRV derived from the use of human intestinal enteroids (HIEs). The replication of multiple circulating HuNoV and HRV genotypes can finally be studied and both in the same non-transformed and physiologically relevant model. Activity of previously described anti-norovirus or anti-rotavirus drugs, such as 2′- C -methylcytidine (2CMC), 7-deaza-2′- C -methyladenosine (7DMA), nitazoxanide, favipiravir and dasabuvir, was assessed against clinically relevant human genotypes using 3D-HIEs. 2CMC showed the best activity against HuNoV GII.4, while 7DMA was the most potent antiviral against HRV. We identified the anti-norovirus and -rotavirus activity of molnupiravir and its active metabolite, N4-hydroxycytidine (NHC), a broad-spectrum antiviral used to treat coronavirus disease 2019 (COVID-19). Molnupiravir and NHC inhibit HuNoV GII.4, HRV G1P[8], G2P[4] and G4P[6] in 3D-HIEs with high selectivity and show a potency comparable to 2CMC against HuNoV. Moreover, molnupiravir and NHC block HRV viroplasm formation, but do not alter its size or subcellular localization. Taken together, molnupiravir inhibits both HuNoV and HRV replication, suggesting that the drug could be a candidate for the treatment of patients chronically infected with either one of these diarrhea causing viruses. • HIEs allow antiviral testing against HuNoV and HRV in the same in vitro model. • Antiviral effect of 2CMC and 7DMA against HuNoV and HRV confirmed in 3D-HIEs. • Molnupiravir and NHC inhibit HuNoV GII.4, HRV (Wa- and DS-1-like) in 3D-HIEs. • Molnupiravir could be a candidate for the treatment of chronic HuNoV or HRV. [ABSTRACT FROM AUTHOR]

Human norovirus is a major cause of viral gastroenteritis in all age groups. The virus is constantly and rapidly changing, allowing mutations and recombination events to create great diversity of circulating viruses. With the start of the COVID-19 pandemic in 2020, a wide range of public health measures were introduced worldwide to control human-to-human transmission of SARS-CoV-2. In Germany, control measures such as distance rules, contact restrictions, personal protection equipment as well as intensive hand hygiene were introduced. To better understand the effect of the measures to control the COVID-19 pandemic on incidence and the molecular epidemiological dynamics of norovirus outbreaks in Germany, we analyzed national notification data between July 2017 and December 2022 and characterized norovirus sequences circulating between January 2018 and December 2022. Compared to a reference period before the pandemic, the incidence of notified norovirus gastroenteritis decreased by 89.7% to 9.6 per 100,000 during the 2020/2021 norovirus season, corresponding to an incidence rate ratio (IRR) of 0.10. Samples from 539 outbreaks were genotyped in two regions of the viral genome from pre-pandemic (January 2018 to February 2020) and samples from 208 outbreaks during pandemic time period (March 2020 to December 2022). As expected, norovirus outbreaks were mainly found in child care facilities and nursing homes. In total, 36 genotypes were detected in the study period. A high proportion of recombinant strains (86%) was found in patients, the proportion of detected recombinant viruses did not vary between the pre-pandemic and pandemic phase. The proportion of the predominant recombinant strain GII.4 Sydney[P16] was unchanged before pandemic and during pandemic at 37.5%. The diversity of most common genotypes in nursing homes and child care facilities showed a different proportion of genotypes causing outbreaks. In nursing homes as well as in child care facilities GII.4 Sydney[P16] was predominant during the whole study period. Compared to the nursing homes, a greater variety of genotypes at the expense of GII.4 Sydney[P16] was detected in child care facilities. Furthermore, the overall proportion of recombinant strain GII.3[P12] increased during the pandemic, due to outbreaks in child care facilities. The COVID-19 pandemic had a high impact on the occurrence of sporadic cases and norovirus outbreaks in Germany, leading to a near suppression of the typical norovirus winter season following the start of the pandemic. The number of norovirus-associated outbreak samples sent to the Consultant Laboratory dropped by 63% during the pandemic. We could not identify a clear influence on circulating norovirus genotypes. The dominance of GII.4 Sydney recombinant strains was independent from the pandemic. Further studies are needed to follow up on the diversity of less predominant genotypes to see if the pandemic could have acted as a bottleneck to the spread of previously minoritized genotypes like GII.3[P12]. [ABSTRACT FROM AUTHOR]

• Rotavirus vaccine has not been introduced into the national immunization program and norovirus vaccines are being developed without a comprehensive understanding of epidemiology in China. • Population-based diarrhea surveillance was conducted in children <5 years of age in the rural north and south of China. • Rotavirus and norovirus are the two most important viral pathogens causing childhood diarrhea in rural China. • Vaccines to protect against rotavirus and norovirus are desirable for prevention of childhood diarrhea in China. Despite the considerable disease burden caused by the disease, rotavirus vaccine has not been introduced into routine national immunization schedule, and norovirus vaccines are being developed without a comprehensive understanding of gastroenteritis epidemiology. To bridge this knowledge gap, we investigated the disease burden of viral gastroenteritis in rural China. Between October 2011 and December 2013, population-based surveillance was conducted in Zhengding and Sanjiang counties in China. Stool samples were collected from children <5 years of age with diarrhea. All specimens were tested for rotaviruses, noroviruses, sapoviruses, enteric adenoviruses, and astroviruses. The most common pathogen causing diarrhea was rotavirus (54.7 vs 45.6 cases/1,000 children/year in Zhengding and Sanjiang, respectively), followed by norovirus (28.4 vs 19.3 cases/1,000 children/year in Zhengding and Sanjiang, respectively). The highest incidence of these viruses was observed in children 6–18 months of age. Among the 5 viral pathogens, rotaviruses caused the most severe illness, followed by noroviruses. Rotavirus and norovirus are the 2 most important viral pathogens causing childhood diarrhea in both northern and southern China; they should be the major targets for viral gastroenteritis prevention strategies among children in China. [ABSTRACT FROM AUTHOR]

Enteric viral infections are among the leading causes of gastroenteritis in children up to five years of age worldwide. This study was aimed to determine the disease severity, incidence, and molecular genotyping of rotaviruses, noroviruses, astroviruses, and enteric adenoviruses as gastroenteritis agents among children up to five years old. Gastroenteritis severity was determined by using the Ruuska and Vesikari score, whereas the incidence of enteric infections and their genotyping were determined by reverse transcription-polymerase chain reaction (RT-PCR) and sequence analysis. Rotaviruses were observed to possess the highest incidence with 10% (18/179) of the cases positives; nevertheless, noroviruses had the highest severe gastroenteritis score (13 ± 3 points). Results indicated that 56% (10/18) of the detected rotavirus strains were genotype G12P[8], 50% (4/8) of noroviruses were GII.4 and 25% (2/8) were genotype GI.8. Out of the sapovirus positive samples, 30% (2/6) were genotyped as GI·I and GII·I. Sixty percent of the astrovirus strains (3/5) were genotype HAstV-2, and 20% (1/5) were genotype HAstV-6. Additionally, one of the adenovirus strains was identified as human mastadenovirus C type 6 specie. The diarrhea severity reduction in children provides evidence that the rotavirus vaccination program in the northwest of Mexico has been successful, even among children infected by the rotavirus emergent strain G12, however, norovirus resulted as the leading severe gastroenteritis-causing agent in children with rotavirus vaccine. • Rotaviruses had the highest incidence; followed by norovirus, sapovirus, astrovirus and adenovirus. • Genotypes: Rotavirus G12P[8]; norovirus GII.4,GI.8; sapovirus GI.I,GII.I; astrovirus, AstV-2, AstV-6; and adenovirus C type 6. • Noroviruses had the highest severity scores, with significant difference in symptoms in comparison with rotavirus. • The rotavirus vaccination program in the northwest of Mexico has been successful even with emergent G12-infections. [ABSTRACT FROM AUTHOR]

• Prevalence of Aichi virus was determined in outpatients from NW Spain. • The virus was detected in 5.0% of the samples among all age groups. • Monoinfections (58.1%) were more abundant than mixed infections (41.9%). • Genotypes A and B were detected in all age groups. In recent years, Aichi virus (AiV) has been involved in acute viral gastroenteritis outbreaks. However, the common pathogenesis of AiV releases more in subclinical infections underestimating the impact of AiV in human health. The present study describes the presence and genetic diversity of AiV in patients with gastroenteritis in Northwestern Spain. Study design: A total of 2667 stool samples, obtained between July 2010 and June 2011, from diarrheic outpatients were studied for detection and molecular characterization of AiV using PCR techniques followed by sequencing and phylogenetic analyses. The virus was detected in 124 (5.0%) of the samples among all age groups. Coinfections were also detected, from the 124 positive samples, 72 (58.1%) were positive only for AiV, whereas mixed contaminations with Norovirus genogroup I or genogroup II, Sapovirus, or other enteric pathogens were detected in 52 (41.9%) samples. A total of 70 positive samples could be genotyped, being characterized as genotype A (58.6%) or B (41.4%). AiV was detected from August to April, being the highest number of AiV positive samples detected during autumn and winter seasons. This survey remarks the importance of emerging enteric viruses in patients who require medical assistance, and offers more information about the real importance of AiV as gastroenteritis agent. [ABSTRACT FROM AUTHOR]

Abstract The Histo-blood group antigens (HBGA) are host genetic factors associated with susceptibility to rotavirus (RV) and human norovirus (HuNoV), the major etiological agents of viral acute gastroenteritis (AGE) worldwide. The FUT2 gene expressing the alpha-1, 2-L- fucosyltransferase enzyme is important for gut HBGA expression, and also provides a composition of the phenotypic profile achieved through mutations occurring in populations with different evolutionary histories; as such, it can be considered a genetic population marker. In this study, Lewis and secretor HBGA phenotyping was performed using 352 saliva samples collected from children between three months and five years old born in the Amazon (Brazil, Venezuela and English Guyana) presenting AGE or acute respiratory infection (ARI), the latter considered as control samples. The total of children phenotyped as secretors was 323, corresponding to 91.80%. From these, 207 (58.80%) had a Le (a + b+) profile. The HBGA profiles were equally found in children with AGE as well as with ARI. The rs1047781 of the FUT2 gene was not detected in DNA from saliva cells with a Le (a+b+) profile. However, mutations not yet described in the FUT2 gene were observed: missense 325A>T, 501C>T, 585C>T, 855A>T and missense substitutions 327C>T [S (Ser) > C (Cys)], 446 T>C [L(Leu) > P(Pro)], 723C>A [N(Asn) > K(Lys)], 724A>T [I(Ile) > F(Phe)], 736C>A [H(His) > N(Asn)]. The SNP distribution in the FUT2 gene of the analyzed samples was very similar to that described in Asian populations, including indigenous tribes. Highlights • The phenotype of Lewis and secretor HBGA identified in young children saliva from the Amazon, is mostly Secretor and Le (a + b+). • Le (a + b+) HBGA phenotype found in the saliva of young children from the Amazon (Brazil), has not the 385A>T SNP of the FUT2 gene. • The SNP distribution in the FUT2 gene detected in saliva of young children from the Amazon is very similar to that described in Asian populations. [ABSTRACT FROM AUTHOR]

• Rapid diagnosis of viral gastroenteritis is necessary for appropriate treatment and control of infection. • The performance of a new multiplex real-time RT-PCR was evaluated. • The overall sensitivity and specificity were highly satisfying. • A wide variety of viral types was correctly detected. • This multiplex assay can be recommended for accurate diagnosis of gastroenteritis. Rotavirus, adenovirus, norovirus and astrovirus are considered to be among the major causes of sporadic cases and outbreaks of acute gastroenteritis globally. Rapid and accurate identification of enteric viruses is still a challenge for the clinical laboratory. Recently, several molecular platforms for the detection of viral enteric pathogens have become available. In this study, the diagnostic accuracy of InGenius Gastrointestinal Viral (GV) Elite Panel, a newly developed one-step multiplex real-time RT-PCR assay simultaneously detecting rotavirus, adenovirus and astrovirus, was evaluated retrospectively analyzing an archival collection of 128 stool samples of children hospitalized with acute gastroenteritis. The overall sensitivity and specificity for the GV assay was 100% and 96.2% for rotavirus, 96.9% and 100% for astrovirus, 100% and 100% for adenovirus, respectively. The InGenius GV assay showed a high concordance with the reference methods and was able to detect all tested genotypes of rotavirus (including G1, G3, G4, G9 and G12P[8] and G2P[4]), adenovirus and astrovirus (AstV-1 and 2). Studies of considerable sample size are required to determine robust Cycle threshold cut-off values to effectively correlate infection to disease. These preliminary results suggest that InGenius GV assay can be recommended as a valuable method for accurate diagnosis of epidemic and sporadic gastroenteritis. [ABSTRACT FROM AUTHOR]

Highlights • Norovirus and rotavirus were found in 18.5% and 20.4% of stool specimens from children <5 years of age with diarrhea in Guatemala in 2014-2015. • The majority of positive samples were detected in children 6–12 months. • Most norovirus infections were caused by GII.4 (63%) and GII.3 (15%) viruses. • Sapovirus genotypes included GI.1, GII.2, GII.5 and GIV viruses. Abstract Background Acute diarrhea is an important cause of morbidity and mortality in children and is associated with approximately 500,000 deaths/year globally. Rotavirus and norovirus are leading causes of acute diarrhea accounting for more than half of this burden. Objective/study design To determine the prevalence and genotype distribution of acute diarrhea caused by rotavirus, norovirus, sapovirus and astrovirus among children <5 years of age at two departments in Guatemala from January 2014 to December 2015, we tested 471 stool specimens (202 samples from hospitalized children and 269 samples from children in ambulatory clinics) by real-time reverse transcription-PCR and genotyped positive samples. Results Rotavirus was detected in 20.4%, norovirus in 18.5%, sapovirus in 7% and astrovirus in 4.2% of the samples. Co-infection of rotavirus and norovirus was found in 2.6% of the samples. Most norovirus (87.4%) and rotavirus (81.3%) infections were detected in children in the 6–12 months age group. The proportion of patients with rotavirus (34%) and norovirus (23%) was higher in hospitalized patients compared to ambulatory patients, whereas the prevalence of sapovirus and astrovirus was similar in both settings. Of the 40 genotyped norovirus strains, 62.5% were GII.4 and 15% GII.3. Sapovirus genotypes included GI.1 (15.4%), GII.2 (15.4%), GII.5 (38.5%) and GIV.1 (30.8%). Conclusions Our data demonstrate that in 2014–2015, gastroenteritis viruses account for 50% of acute diarrhea in children younger than 5 years of age in Guatemala, highlighting the importance of continuous surveillance to guide impact of the current rotavirus vaccine and formulation of future norovirus vaccines. [ABSTRACT FROM AUTHOR]

Highlights • Chronic diarrhea due to persistent sapovirus in immunocompromised individuals. • Accumulation of amino acid mutations predominantly within VP1 P2 protruding domain. • Reduction of immunosuppression was associated with decrease of viral load and clearance of sapovirus in stool. Abstract Background Sapovirus is a common cause of self-limiting diarrhea. In immunocompromised individuals chronic infections occur, but are incompletely investigated. Objectives To investigate viral evolution in immunocompromised hosts during chronic sapovirus infection. Study design From January 2010 to September 2018 stool samples of 5333 in-patients were analyzed for the presence of sapovirus RNA by real-time RT-PCR. In follow-up samples of chronic diarrhea cases nucleic acid sequencing of sapovirus genomes was performed. Amino acid mutations were identified by alignments and compared to data from GenBank. Sapovirus genotypes were assessed by phylogenetic analysis of viral capsid gene (VP1). Results Sapovirus RNA was present in 146 stool samples of 95 patients (1.8%), most frequently in young children and infants. In patients older than 14 years, sapoviruses were exclusively detected in immunocompromised patients. Chronic diarrhea occurred in almost one third of the sapovirus positive immunocompromised individuals (n = 5) and was established by different sapovirus genotypes (GI.2, GII.1, GII.3). The maximum observed duration of sapovirus shedding was 119 days. Accumulation of amino acid mutations during chronic infection was most often detected within VP1 P2 protruding subdomain. Reduction of immunosuppression was associated with decrease of viral load and clearance of sapovirus in stool. Conclusions Clinicians should consider immunocompromised individuals at risk to develop chronic diarrhea due to persistence of SaV infection. The identified VP1 mutations contribute to an understanding of sapovirus-host interactions. For further conclusions regarding virus immune escape and altered viral fitness structural data on sapovirus capsid and virus/receptor complex are necessary. [ABSTRACT FROM AUTHOR]

Abstract Human parechoviruses (HPeV) are ubiquitous and mainly occur in early infancy. They are known to cause various clinical manifestations including acute gastroenteritis. To gain insight into the diversity of circulating HPeV genotypes, stool samples from patients (n = 539) with clinical signs of infectious gastroenteritis which showed negative results for other common viral and bacterial enteric pathogens were obtained during three years, 2008 to 2010. Real-time RT-PCR showed HPeV RNA in 34 (6.3%) of the samples. The HPeV detection rate was highest (8.8%) in samples derived from infants and young children under the age of two years. Genotyping was based on VP3/VP1 junction nucleic acid sequences and revealed predominant HPeV-1B (n = 16) and HPeV-3 (n = 12) strains. Those prevailed minor HPeV-6 (n = 3) as well as HPeV-2, −4 and −5 (n = 1, each) strains. To ascertain the assigned HPeV-2 genotype of uncommon strain LPZ04-2008, analysis of complete coding sequences was performed. In complete VP1 analysis strain LPZ04-2008 showed 81.2% nucleic acid identity with HPeV-2 reference strain Williamson. In phylogenetic analysis VP1 of strain LPZ04–2008 clustered with a recent HPeV-2 strain from the UK. Regarding clinical manifestations, severe disease occurred HPeV-1B, −3 and − 6 infections. In conclusion, this paper a high genetic diversity of HPeV in stool samples, including rare strains. The investigation adds data on the whole coding sequences of the rare HPeV-2 strain. Genotyping results confirm previously reported association of more severe illness with HPeV-3 and HPeV-1B strains. Highlights • High genetic diversity of human parechoviruses in stool samples • Full-coding sequences of a rare human parechovirus-2 strain • Association of severe disease with human parechovirus type 1, 3 and 6 [ABSTRACT FROM AUTHOR]

Rotavirus B (RVB) is a causative agent leading to acute viral gastroenteritis diarrhea in both children and young animals, and has been commonly detected in piglets. In order to determine the causative agent of diarrheal outbreak occurring in December 2022 in piglets from a pig herd in Luoyang, Henan province of China, four common viral pathogens causing piglet diarrhea-three coronaviruses and rotavirus A (RVA) were first tested and found negative, therefore metagenomic sequencing was performed to explore other potential pathogens in the diarrheal samples. Unexpectedly, the most abundant viral reads mapped to RVB, and were de novo assembled to complete 11 viral gene segments. Sequence comparisons revealed that 5 gene segments encoding VP1, VP2, VP3, NSP3 and NSP4 of RVB strain designated as HNLY-2022 are most closely related to RVB strains derived from herbivores with low nucleotide similarities of 65.7–75.3%, and the remaining segments were relatively close to porcine RVB strains with the VP4 gene segment showing very low nucleotide identity (65.0%) with reference strains, indicating HNLY-2022 is a new reassortant RVB strain. Based on the previously proposed genotype classification criterion, the genotype constellation of RVB strain HNLY-2022 is G6-P[6]-I4-R6-C6-M6-A7-N5-T7-E5-H4 with more than half of the genotypes (P[6], R6, C6, M6, T7 and E5) newly reported. Therefore, the new reassortant RVB strain is the likely causative agent for the diarrheal outbreak of piglets occurred in China and more epidemiological studies should be conducted to monitor the spread of this newly identified porcine RVB strain. • Outbreak of piglet diarrhea occurred in Henan province of China was associated with a new rotavirus B. • HNLY-2022 is a reassortant RVB strain with the gene segments probably arose from pigs and herbivores. • The genotypes P[6], R6, C6, M6, T7 and E5 of RVB were firstly identified. [ABSTRACT FROM AUTHOR]

Highlights • Rotavirus A were the most frequently detected viral gastroenteritis pathogen. • Recombinant noroviruses were circulating in Southwestern Nigeria. • A not yet detected zoonotic astrovirus was found in AGE in a Nigerian infant. • First report of the detection of aichivirus among diarrheic child in Nigeria. Abstract Background Viruses are the leading cause of acute gastroenteritis in children worldwide. Understanding of the occurrence and genetic diversity of these viruses can help to prevent infections. Objectives The present study describes the presence, genetic diversity and possible recombination of five enteric viruses in children with gastroenteritis in Southwestern Nigeria. Study design From August 2012 to December 2013, stool samples and sociodemographic data of 103 diarrheic children <5 years were collected to detect and characterize rotavirus A, norovirus, human astrovirus, aichivirus and sapovirus using PCR techniques followed by sequencing and phylogenetic analyses. Results At least one virus was identified in 58.3% (60/103) of the stool samples. Rotavirus, norovirus and astrovirus were detected in 39.8% (41/103), 10.7% (11/103), and 6.8% (7/103) respectively. Notably, aichivirus was detected for the first time in Nigeria (1/103; 0.97%). Sapovirus was not detected in the study. Co-infections with rotavirus were observed in eight samples either with norovirus or astrovirus or aichivirus. Phylogenetic analyses of different genome regions of norovirus positive samples provided indication for recombinant norovirus strains. A novel astrovirus strain closely related to canine astrovirus was identified and further characterized for the first time. Conclusions Viruses are the common cause of acute gastroenteritis in Nigerian infants with rotavirus as most frequently detected pathogen. New norovirus recombinants and a not yet detected zoonotic astrovirus were circulating in Southwestern Nigeria, providing new information about emerging and unusual strains of viruses causing diarrhea. [ABSTRACT FROM AUTHOR]

Abstract Frozen berries contaminated with human norovirus (hNV) have been frequently identified as cause of foodborne gastroenteritis. To prevent virus transmission, heating can be applied to the berries. Here, the thermal inactivation of hNV in strawberry puree was assessed. Due to the lack of a reliable system for hNV infectivity assessment, capsid integrity assays using RNase treatment prior to detection of protected viral RNA were applied. In addition, murine norovirus (MNV) and Tulane virus (TV) served as surrogates. The method was optimized to allow direct comparisons between the viruses. The results indicated that infectious MNV is slightly more stable than TV. Both viruses were completely inactivated (>7 log 10 reductions) after treatment at 80 °C for 8 s. TV infectivity decreased faster than capsid-protected RNA. In addition, TV showed a markedly lower stability compared to hNV using capsid integrity assays. Predictive models were generated for all viruses and D - and ɀ-values were calculated. The tertiary model covering reduction of hNV capsid-protected RNA between 50 and 80 °C suggests that temperatures under 70 °C are not reliable for inactivation. About 3.5 log 10 reductions are achieved by heating at 80 °C for 8 s. Further studies should focus on the model validation with direct hNV infectivity data. Highlights • Optimization of a method for testing heat inactivation of viruses in berry puree. • Comparison of heat inactivation of human norovirus and surrogates in strawberry puree. • >7 log-reduction of Tulane virus and murine norovirus at 80 °C for 8 s. • 3.5 log-reduction of capsid-protected RNA of human norovirus at 80 °C for 8 s. • Generation of predictive models for inactivation of human norovirus and surrogates. [ABSTRACT FROM AUTHOR]

Abstract Viral gastroenteritis is a major global public-health threat. All age groups are susceptible for this infection, but its most serious consequences affect children. Rotavirus , Coxsackievirus and Adenovirus are the most common viruses that cause gastroenteritis. Herein, we synthesized novel pyrrole, pyrrolo[2,3‑ d ]pyrimidine and pyrrolo[3,2‑ e ][1,2,4]triazolo[4,3‑ c ]pyrimidine derivatives. The non-toxic doses of these compounds were determined using BGM cell lines. We examined all the new compounds for their anti-viral activities against Rotavirus Wa strain and Coxsackievirus B4. Compounds 2a , 2d , 5a , 5c , 5d , 7b , 7j , 7n , 14b , 14c , 14e and 14f exhibited significant antiviral activity. We interpreted the action of these compounds using molecular docking against the homology models of viral polymerase enzymes of these viruses. RMSD value of 5d/Coxsackievirus was higher than the RMSD value for 5d/rotavirus and hence better as a stability parameter, which can be correlated to the biological activity. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Highlights • A multiplex PCR was developed to detect five viruses associated with enteric disease in pigs. • The assay was specific for detecting one or more of the viruses. • The detection limits of the assay were less than 50 copies per reaction. • This assay provided a valuable diagnostic tool for the detection of these five viruses. Abstract Porcine viral diarrhea, mainly caused by porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine group A rotaviruses (RVA), porcine group C rotaviruses (RVC) and porcine circovirus 2 (PCV2), is a serious global problem, resulting in substantial economic losses to the swine industry. For fast and reliable diagnosis of the causative agent associated with viral diarrhea in pigs, an inexpensive and easy to perform gel-based multiplex PCR assay was developed in this study to detect and differentiate the different viruses by amplicon size. The assay was able to distinguish between all five viral agents without cross-reacting with other non-target pig viruses. The detection limits of the assay per reaction were 5 copies for PEDV, TGEV, RVC and PCV2 and 50 copies for RVA for the singleplex assays and 50 copies when all five viruses were multiplexed. Sixty-nine field samples were used to validate the developed multiplex assay. The overall prevalence of positive samples was 44.9% (31/69). PCV2 was detected in 37.7% of the samples, PEDV and RVC each in 4.3%, TGEV in 2.9%, and RVA was detected in 1.4% of the samples tested. A total of 5.8% of the samples were co-infected by two or more viruses, and the results of the multiplex assay were in agreement to those obtained by single PCR assays. These findings suggest that the developed cost-effective multiplex assay is specific, sensitive, and will serve as a valuable diagnostic tool for the rapid differential detection of these five viruses and for molecular epidemiological studies and diarrhea disease management. [ABSTRACT FROM AUTHOR]

Background Sapoviruses are responsible for sporadic and epidemic acute gastroenteritis worldwide. Sapovirus typing protocols have a success rate as low as 43% and relatively few complete sapovirus genome sequences are available to improve current typing protocols. Objective/study design To increase the number of complete sapovirus genomes to better understand the molecular epidemiology of human sapovirus and to improve the success rate of current sapovirus typing methods, we used deep metagenomics shotgun sequencing to obtain the complete genomes of 68 sapovirus samples from four different countries across the Americas (Guatemala, Nicaragua, Peru and the US). Results VP1 genotyping showed that all sapovirus sequences could be grouped in the four established genogroups (GI (n = 13), GII (n = 30), GIV (n = 23), GV (n = 2)) that infect humans. They include the near-complete genome of a GI.6 virus and a recently reported novel GII.8 virus. Sequences of the complete RNA-dependent RNA polymerase gene could be grouped into three major genetic clusters or polymerase (P) types (GI.P, GII.P and GV.P) with all GIV viruses harboring a GII polymerase. One (GII.P-GII.4) of the new 68 sequences was a recombinant virus with the hotspot between the NS7 and VP1 regions. Conclusions Analyses of this expanded database of near-complete sapovirus sequences showed several mismatches in the genotyping primers, suggesting opportunities to revisit and update current sapovirus typing methods. [ABSTRACT FROM AUTHOR]

Objectives To estimate the trend in incidence of rotavirus gastroenteritis (RVGE) hospitalization among children aged <5 years in Japan during pre- and post-vaccine periods (2009–2011 and 2012–2015). Study design This retrospective observational study used a health insurance claims database (constructed by Japan Medical Data Center Co., Ltd.). Rotavirus vaccine became commercially available in 2011. We analyzed data of all children aged <5 years between January 2009 and December 2015. We estimated the incidence rate (IR) of RVGE hospitalization per 1000 person-years from 2009 to 2015 and incidence rate ratio (IRR) of post-vaccine years compared with the averaged pre-vaccine years. IRs and IRRs were also estimated by age group. Primary analysis was limited to the rotavirus season (January to June) of each year. Results The IR was 6.3–9.3 in pre-vaccine years, 2.3 in 2014, and 3.0 in 2015; the decline was estimated to be 71% in 2014 and 61% in 2015 (p < 0.01). By age group, reduction in hospitalizations began in 2013 among children <1 year old, followed by children aged 1 to <5 years in 2014. In the 2014 season, a 65% reduction in RVGE hospitalization was observed in children aged 36 to <60 months, although this age group was unlikely to be vaccinated. Conclusions A substantial decline of RVGE hospitalization in 2014 and its persistence was observed among children aged <5 years in Japan after introduction of rotavirus vaccine, although not included in the national immunization program. Indirect effects of rotavirus vaccination were suggested in the 2014 season. [ABSTRACT FROM AUTHOR]

Human noroviruses (HuNoVs) are the predominant etiological agent of viral gastroenteritis in all age groups worldwide. Mutations over the years have affected noroviruses' responses to environmental conditions due to the arrangement of amino acid residues exposed on the VP1 capsid surface of each strain. The GII.4 HuNoV genotype has been the predominant variant for decades, while the GII.17 genotype has often been detected in East Asia since 2014. Here, GII.17 and GII.4 baculovirus-expressed VLPs (virus-like particles) were used to study the biological (binding to HuNoV ligand, namely the ABO and Lewis antigens) and physicochemical properties (size, morphology, and charge) of the HuNoV capsid under different conditions (temperature, pH, and ionic strength). GII.17 showed stability at low and high ionic strength, while GII.4 aggregated at an ionic strength of 10 mM. The nature of the buffers influences the morphology and stability of the VLPs. Here, both VLPs were highly stable from pH 7–8.5 at 25 °C. VLPs retained HBGA binding capability for the pH, ionic strength and temperature encountered in the stomach (fed state) and the small intestine. Increasing the temperature to above 65 °C altered the morphology of VLPs, causing aggregation, and decreased their affinity to HBGAs. Comparing both isolates, GII.17 showed a better stability profile and higher affinity to HBGAs than GII.4, making them interesting candidate particles for a future norovirus vaccine. Biological and physicochemical studies of VLPs are as pertinent as ever in view of the future arrival of VLP-based HuNoV vaccines. [Display omitted] • pH and temperature affect human norovirus structure and biological properties. • Ionic strength doesn't affect VLP structure and receptor binding capacity. • VLPs are active during gastric fed state but not in the fasted state. • Aggregated VLP is associated with loss of activity. [ABSTRACT FROM AUTHOR]

• Enteric viruses were detected by PCR in 45.3% of diarrheic hospitalized children. • Despite vaccination efforts rotavirus remained the most prevalent and sever virus. • An off-season surge of rotavirus cases occurred in the 2nd COVID-19 pandemic year. • Some viral AGE mimicked clinical dysentery despite excluding bacterial coinfections. • Hospital-acquired AGE were more common in sapovirus and astrovirus infections. Multiplex-PCR is a valuable tool for diagnosing viral acute gastroenteritis (AGE), enabling the detection of multiple pathogens. However, distinguishing between active disease and shedding poses challenges. This study aimed to evaluate viral AGE epidemiology and compare clinical characteristics among the five most common viruses. Rotavirus vaccine was introduced in 2010, with 70% coverage achieved in southern Israel in two years. All rectal swabs for multiplex-PCR targeting rotavirus, norovirus, adenovirus, astrovirus and sapovirus from hospitalized diarrheic children <5 years were included, from December 2017 through March 2022. Detection of the same virus within two months was considered a single episode. Clinical analysis included episodes with single-virus detection and negative bacterial PCR. Among 5,879 rectal swabs, 2,662 (45.3%) tested positive for at least one virus, with 245 (9.2%) showing multiple virus detection. Rotavirus was the most prevalent. While rotavirus exhibited typical winter-spring seasonality in 2018–19, an unusual off-season surge was observed during the second year of the COVID-19 pandemic. Among negative bacterial PCR episodes, 34.6% had mucus stool, 5.9% had bloody stool, and 29.3% received antibiotics. Astrovirus or sapovirus infections were associated with higher rates of hospital-acquired AGE and immunodeficiency (P <0.05), whereas rotavirus infections had higher rates of dehydration severity and acute kidney injury (P <0.05). Enteric viruses were detected in 45.3% of rectal swabs from hospitalized children with diarrhea. Despite vaccination efforts, rotavirus remained prevalent and caused more severe disease. Continuous surveillance using multiplex-PCR is crucial for accurate management and future prevention strategies for viral AGE. [ABSTRACT FROM AUTHOR]

• Blockade monoclonal antibodies showed significantly reduced binding against GII.6 VP1 carrying H383Y, D387N, V390D, and T391D point mutations. • Blockade monoclonal antibody binding region was mapped to residues 380–395. • Key residues between residues 380 to 395 showed intra-cluster conservation and inter-cluster variations. Noroviruses (NoVs) are the leading agent that causes acute viral gastroenteritis worldwide. Sporadic cases of GII.6 NoV have been reported primarily in addition to occasional outbreaks. Using the major capsid protein VP1 of GII.6 NoV derived from three distinct clusters, we demonstrated three blockade monoclonal antibodies (mAbs, 1F7, 1F11, and 2B6) generated previously exhibited cluster-specific binding effects. Combining sequence alignment and blocking immune epitopes, we sequentially designed a total of 18 mutant proteins containing one, two, or three mutations, or swapped regions. Indirect enzyme-linked immunosorbent assay (ELISA) demonstrated that the three blocking mAbs lost or showed significantly reduced binding for H383Y, D387N, V390D, and T391D mutant proteins. Combining data from mutant proteins with swapping regions and point mutations, the binding region of the three mAbs was mapped to residues 380–395. Sequence alignment of this region showed within-cluster conservation and between-cluster variations, further strengthening the idea of blockade epitope-mediated evolution of NoV. [ABSTRACT FROM AUTHOR]

Background It is important to understand the diagnostic accuracy of multiplex panels such as the Luminex xTAG ® Gastrointestinal Pathogen Panel (GPP) as they are increasingly employed for routine diagnostics worldwide. Recent evaluations in our laboratory identified lower detection rates of norovirus genogroup II (NoV GII) using GPP compared to our laboratory-developed RT-qPCR, Gastroenteritis Virus Panel (GVP). Objectives To characterize the cases of discordant NoV GII results between GPP and GVP and determine the sensitivity of the two assays for specific NoV GII genotypes. Study design We genotyped discordant NoV GII strains identified in stool samples or rectal swabs collected prospectively from a cohort of children with acute gastroenteritis between December 2014 and July 2016. The sensitivities of GVP and GPP for NoV GII were compared by analyses of GVP threshold cycle (Ct) and ten-fold serial dilutions of positive samples of various NoV GII genotypes. Results All discordant samples (63/607) were NoV GII positive by GVP but negative by GPP. Twenty-two were successfully genotyped, fourteen of which were NoV GII genotype 2 (GII.2). The median Ct value of concordant positives was lower than that of discordant results (19.8 vs. 33.7; P < 0.0001). GVP was 10 and at least 10,000-fold more sensitive than GPP in detecting NoV GII.3 and GII.2, respectively, but has similar sensitivity for NoV GII.4. Discordant GII.2 variant differed genetically from concordant GII.2 variants. Conclusions GPP has lower sensitivity to detect NoV GII.2 than GVP and its use may lead to undetected cases clinically, and an underestimation of NoV disease burden at the population level. [ABSTRACT FROM AUTHOR]

Background Viruses are major etiological agents of childhood gastroenteritis. In recent years, several molecular platforms for the detection of viral enteric pathogens have become available. Objective/study design We evaluated the performance of three multiplex platforms including Biofire’s Gastrointestinal Panel (FilmArray), Luminex xTAG ® Gastrointestinal Pathogen Panel (GPP), and the TaqMan Array Card (TAC) for the detection of five gastroenteritis viruses using a coded panel of 300 archived stool samples. Results The FilmArray detected a virus in 199 (96.1%) and the TAC in 172 (83.1%) of the 207 samples (187 samples positive for a single virus and 20 samples positive for more than one virus) whereas the GPP detected a virus in 100 (78.7%) of the 127 (97 positive for one virus and three positive for more than one virus) samples. Overall the clinical accuracy was highest for the FilmArray (98%) followed by TAC (97.2%) and GPP (96.9%). The sensitivity of the FilmArray, GPP and TAC platforms was highest for rotavirus (100%, 95.8%, and 89.6%, respectively) and lowest for adenovirus type 40/41 (97.4%, 57.9% and 68.4%). The specificity of the three platforms ranged from 95.6% (rotavirus) to 99.6% (norovirus/sapovirus) for the FilmArray, 99.6% (norovirus) to 100% (rotavirus/adenovirus) for GPP, and 98.9% (astrovirus) to 100% (rotavirus/sapovirus) for TAC. Conclusion The FilmArray demonstrated the best analytical performance followed by TAC. In recent years, the availability of multi-enteric molecular testing platforms has increased significantly and our data highlight the strengths and weaknesses of these platforms. [ABSTRACT FROM AUTHOR]

Rotavirus is one of the leading causes of acute gastroenteritis in infants and young children. RVAs infect not only humans but also a wide range of mammals including rats, which represent a reservoir of several other zoonotic pathogens. Due to the segmented nature of the RVA genome, animal RVA strains can easily adapt to the human host by reassortment with co-infecting human viruses. This study aims to detect and characterize RVA in the intestinal content of Italian sinantropic rats ( Rattus rattus ). Out of 40 samples examined following molecular approach, one resulted positive for RVA. The molecular characterization of VP1-4, 6 and 7, and NSP1-5 genes by sequencing revealed the genomic constellation G3-P[3]-I1-R11-C11-M10-A22-N18-T14-E18-H13. This uncommon genomic combination includes: the VP1-4,VP7, the NSP1, 3, 4 and 5 gene segments, closely related to those of RVA from rodents, the N18 novel genotype established for the NSP2 gene segment and the human Wa-like VP6 gene, suggesting interspecies reassortment. [ABSTRACT FROM AUTHOR]

Purpose The aim of this study was to determine the incidence and genetic diversity of astrovirus (AstV) detected in children hospitalized for gastroenteritis (GE). Methods A multi-center, hospital-based surveillance study was conducted across Lebanon to investigate the incidence of AstV among diarrheal hospitalizations. Viral RNA was extracted from stool samples collected between 2011 and 2013 from children, below the age of 5 years, hospitalized for GE at six medical centers across Lebanon. Demographic and clinical data were collected and analyzed. RNA of eligible samples ( n = 739) was screened by two AstV-specific PCR assays followed by genotype-specific PCR. Sanger sequencing and phylogenetic analysis were performed for genotypic characterization. Results Overall, 5.5% (41/739) of rotavirus-negative stool samples collected from hospitalized children < 5 years old tested positive for AstV infection. AstV infections were detected all year long. Diarrhea, dehydration, vomiting and fever were the most common symptoms associated with AstV infections. Children aged 48–59 months had the highest incidence of AstV. Using the Vesikari Scoring System to assess clinical severity, 85.4% of children with AstV had a score > 11, indicating severe GE. Genotype-specific PCR identified 22 classical and 4 MLB-like AstV specimens. Further sequencing and phylogenetic analysis of orf1b and orf2 genes revealed that AstV classical 1–3, 5, 6, and 8, MLB-1, VA-1 and -2 genotypes circulated in Lebanon. Recombination between classical AstV strains was detected in several cases as evident by the lack of congruency in the tree topologies of the orf1b and orf2 . Two cases of mixed infections between classical and non-classical genotypic strains were recorded. Conclusion High genetic diversity was detected among AstVs in Lebanon. AstVs are associated with 5.5% of non-rotavirus GE-associated hospitalizations in children under five years in Lebanon. [ABSTRACT FROM AUTHOR]

Human cosavirus and saffold virus are both newly discovered members of the Picornaviridae family. It has been suggested that these viruses may be the causative agents of acute gastroenteritis. In this study, 1093 stool samples collected from patients with acute gastroenteritis between January 2014 and December 2016, were screened for cosavirus and saffold virus using reverse transcription-polymerase chain reaction. The viral genotypes were then established via nucleotide sequencing. Here, cosavirus was detected in 16 of 1093 stool samples (1.5%) and saffold virus was detected in 18 of 1093 stool samples (1.6%). The saffold virus genotypes 1 (16.7%), 2 (50%) and 6 (33.3%), and the cosavirus genetic groups A (87.5%), C (6.25%) and D (6.25%), were all identified across the three-year study period. Interestingly, saffold virus genotype 6 has now been detected for the first time in Thailand. The present study provides the prevalence of cosavirus and saffold virus with the emergence of saffold virus genotype 6 in Thailand. [ABSTRACT FROM AUTHOR]

Bocaparvoviruses have been studied extensively owing to their ability to cause respiratory illness or gastroenteritis in humans. Some bocaparvoviruses have been detected in non-human primates (gorillas and chimpanzees), but the diversity and evolution of these viruses are not fully understood. In this study, we collected 107 fecal samples from wild western lowland gorillas in Moukalaba-Doudou National Park in Gabon to investigate the presence of bocaparvoviruses. Using a combination of pan-bocaparvovirus PCR and individual identification by microsatellite genotyping, we found that two samples from two apparently healthy infant gorillas were positive for bocaparvovirus. Sequencing and phylogenetic analyses revealed that the two gorilla bocaparvovirus strains are nearly identical and are closely related to viruses in the species Primate bocaparvovirus 2 (with 86.0% nucleotide identity to a human bocavirus 2 isolate). To our knowledge, this is the first report showing the presence of a non-human primate bocaparovirus within Primate bocaparvovirus 2 . Our findings provide novel insights into the diversity and evolution of bocaparvoviruses and highlight the importance of surveying these viruses for the safe management of gorilla-based ecotourism. [ABSTRACT FROM AUTHOR]

Viral gastroenteritis is a major health problem with significant morbidity and economic consequences. Viral gastroenteritis is caused by a number of viruses, including norovirus, rotavirus, adenovirus, astrovirus, and sapovirus. Conventional diagnosis is based on direct antigen detection and electron microscopy, however enzyme immunoassay’s are insensitive and not available for all relevant pathogens, and electron microscope (EM) is no longer routinely carried out in most laboratories. Most laboratories now offer norovirus real-time PCR testing however the availability of other assays is variable. Commercial methods for the detection of inflectional intestinal disease (IID) are available but these can be expensive and are not commonly used. This paper describes the development of a single multiplex assay for the simultaneous detection of adenovirus, astrovirus, rotavirus and sapovirus from stool samples. The multiplex was evaluated by assessing endpoint sensitivity, specificity, panel of clinical samples, quality control (QC) panel and the robustness and reproducibility of the multiplex. [ABSTRACT FROM AUTHOR]

Gastrointestinal tract perforations are relatively rare in children. Patients who receive repeated blood transfusions are susceptible to iron overload with its own associated complications. To obviate these complications, iron chelation therapy with deferasirox is the treatment of choice. One of the rare complications of chronic treatment with deferasirox is gastrointestinal perforations. The aim of this report is to outline aspects of diagnosis, management, and the role of minimal invasive surgery in the management of this rare complication. This report describes a case of duodenal perforation in a 5-year-old patient with beta-thalassemia receiving multiple blood transfusions and on chronic chelation with deferasirox. She presented to the emergency department with vomiting and diarrhea of 5 days duration and diagnosed to have acute viral gastroenteritis. She was admitted to the pediatric medical ward and later on the same day she developed severe abdominal pain, mostly in the epigastric region. On physical examination, she was initially afebrile but later developed fever (38.9 °C). She was also tachycardic (a heart rate of 130 beats/min), and tachypneic (a breathing rate of 24–28 breaths per minute). Her blood pressure was 115/76 mmHg. Her abdominal examination revealed generalized abdominal tenderness with guarding and mildly reduced bowel sounds. An erect abdominal x-ray revealed free intraabdominal air which was confirmed by an abdominal CT scan. The diagnosis of gastrointestinal perforation was made, and the patient was prepared for an emergent diagnostic laparoscopy which revealed a duodenal perforation in the anterior aspect of the first part of the duodenum. Primary repair of the perforation was done, followed by reinforcement with a Graham patch and peritoneal lavage. Postoperatively she did well and was discharged home on the 8th postoperative day. Deferasirox induced duodenal perforation is very rare. Duodenal perforation should be suspected in patients with severe gastrointestinal symptoms and abdominal tenderness while on Deferasirox, especially at high doses (30+ mg/kg). Awareness of this rare complication is important to avoid delay in diagnosis and treatment with its known sequalae. Once suspected the diagnosis can be confirmed and managed laparoscopically. [ABSTRACT FROM AUTHOR]

Coronaviruses tend to efficiently evade innate immune sensing. Alpha-coronaviruses interfere with the type I interferon (IFN) response in various ways, ensuring the limited activation of IFN responses. Transmissible gastroenteritis virus (TGEV), an Alphacoronavirus genera virus, is an important pathogen that mainly infects piglet, but little is known about the activation of the host immune response. We show that TGEV induces a delayed activation of the IFN response in intestinal epithelial cells. Briefly, IFN-β expression induced by TGEV infection is delayed with respect to that induced by poly(I:C) transfection. In addition, some of the IFN-stimulated genes (ISGs) were up-regulated in the early infection stage without obvious expression of IFN-β. Moreover, we show that activation of IFN responses induced by poly(I:C) could inhibit viral replication in the early infection stage, but failed in the late infection stage in IPEC-J2 cells. Finally, the activation of IFN responses induced by TGEV infection cannot inhibit viral replication. Taken together, this study provides a preliminary analysis of an interaction between TGEV and IFN-β responses of intestinal epithelial cells. [ABSTRACT FROM AUTHOR]

Human noroviruses are the most common cause of acute viral gastroenteritis, and the environmental persistence of these viruses contributes to their transmissibility. Environmental sampling is thus an important tool for investigating norovirus outbreaks and for assessing the effectiveness of cleaning and decontamination regimens. The purpose of this study was to evaluate a sampling material (wipes) for their efficacy at recovering human norovirus from hard surfaces and foods. Dilutions of a human norovirus GII.4 stool specimen derived from an outbreak were applied to hard surfaces (stainless steel and ceramic) and the surfaces of representative foods (green pepper, apple, tomato, and cheese). The viruses were recovered at various times postinoculation using the wipes, followed by RNA extraction and reverse transcription quantitative PCR. Recovery efficiency ranged from 74% to almost 100% for all artificially inoculated hard surfaces and for most fresh produce surfaces. Less efficient recovery was observed for cheese. Viral RNA could be recovered from select surfaces for up to 7 days postinoculation, with a <1 log reduction in genome copy number. In field tests, 24 (11%) of 210 environmental samples collected during winter 2012 from restrooms in North Carolina were presumptively positive for human norovirus, and six of these samples were confirmed as GII.4 by sequencing. These wipes may be a valuable tool for investigations of norovirus outbreaks and studies of norovirus prevalence. [ABSTRACT FROM AUTHOR]

Human norovirus (HuNoV) is the primary cause of viral gastroenteritis worldwide. Fresh blueberries are among high risk foods associated with norovirus related outbreaks. Therefore, it is important to assess intervention strategies to reduce the risk of foodborne illness. The disinfection efficiency of decontamination methods is difficult to evaluate for fruits and vegetables due to an inconsistent degree of contamination and irregular surface characteristics. The inactivation efficiency and mechanism of murine norovirus 1 (MNV-1, a surrogate for HuNoV) was studied on an experimentally prepared solidified agar matrix (SAM) to simulate blueberries using different wavelengths (A, B, C) of UV light both with and without TiO 2 photocatalysis (TP). MNV-1 was inoculated on exterior and interior of SAM and inactivation efficiencies of different treatments were investigated using a number of assays. Initial inoculum levels of MNV-1 on the SAM surface and interior were 5.2 log PFU/mL. UVC with TiO 2 (UVC-TP) achieved the highest level of viral reduction for both externally inoculated and internalized MNV-1. Externally inoculated MNV-1 was reduced to non-detectable levels after UVC-TP treatment for 5 min while there was still a 0.9 log viral titer after UVC alone. For internalized MNV-1, 3.2 log and 2.7 log reductions were obtained with UVC-TP and UVC alone treatments for 10 min, respectively. The Weibull model was applied to describe the inactivation behavior of MNV-1, and the model showed a good fit to the data. An excellent correlation between the steady-state concentration of OH radicals ([ OH] ss ) and viral inactivation was quantified using a para –chlorobenzoic acid ( p CBA) probe compound, suggesting that OH radicals produced in the UV-TP reaction were the major species for MNV-1 inactivation. Transmission electron microscopy images showed that the structure of viral particles was completely disrupted with UVC-TP and UVC alone. SDS-PAGE analysis showed that the major capsid protein VP1 was degraded after UVC-TP and UVC alone. Real-time RT-qPCR analysis showed that UVC-TP and UVC alone caused a reduction in the level of viral genomic RNA. Propidium monoazide (PMA) pretreatment RT-qPCR analysis showed that UVC-TP caused damage to the viral capsid protein in addition to viral genomic RNA. UVC both with and without TiO 2 was more effective for MNV-1 inactivation than UVB and UVA. Thus, UVC-TP disinfection aimed to reduce levels of food-borne viruses can inactivate viruses present on the surface and internalized in the interior of blueberries. [ABSTRACT FROM AUTHOR]

Noroviruses are the major cause of global viral gastroenteritis with short incubation times and small inoculums required for infection. This creates a need for a rapid molecular test for norovirus for early diagnosis, in the hope of preventing the spread of the disease. Non-chemists generally use off-the shelf reagents and natural DNA to create such tests, suffering from background noise that comes from adventitious DNA and RNA (collectively xNA) that is abundant in real biological samples, especially feces, a common location for norovirus. Here, we create an assay that combines artificially expanded genetic information systems (AEGIS, which adds nucleotides to the four in standard xNA, pairing orthogonally to A:T and G:C) with loop-mediated isothermal amplification (LAMP) to amplify norovirus RNA at constant temperatures, without the power or instrument requirements of PCR cycling. This assay was then validated using feces contaminated with murine norovirus (MNV). Treating stool samples with ammonia extracts the MNV RNA, which is then amplified in an AEGIS-RT-LAMP where AEGIS segments are incorporated both into an internal LAMP primer and into a molecular beacon stem, the second lowering background signaling noise. This is coupled with RNase H nicking during sample amplification, allowing detection of as few as 10 copies of noroviral RNA in a stool sample, generating a fluorescent signal visible to human eye, all in a closed reaction vessel. [ABSTRACT FROM AUTHOR]

Background Diarrhoea in children is a common disease; understanding the incidence of causative viruses can aid infection control and vaccine development. Objectives Describe the incidence and characteristics of gastroenteric viruses including norovirus genotypes in a paediatric hospital cohort. Study design Norovirus, adenovirus, sapovirus, astrovirus, rotavirus qPCR and norovirus genotyping results for all stool specimens (n = 4786; 1393 patients) at a UK paediatric tertiary referral hospital June 2014–July 2015. Results and discussion 24% (329/1393) of patients were positive for a GI virus; the majority were positive for norovirus (44%, 144/329) or adenovirus (44%, 146/329). The overall incidence of rotavirus (2%) is reduced compared to pre-vaccination studies; however the incidence of other GI viruses has not increased. Norovirus infections had a significantly higher virus burden compared to other GI viruses (P ≤0.03); sapovirus infections had the lowest viral burden. The number of norovirus cases per month did not follow the typical winter seasonal trend of nationally reported outbreaks. The number of cases per month correlates with the number of hospital admissions (R = 0.703, P = 0.011); the number of admissions accounts for 50% of the variability in number of cases per month. The breadth of genotypes seen (48% non-GII.4), suggests a community source for many norovirus infections and has implications for vaccine development. All GI viruses caused chronic infections, with the majority (50–100%) in immunocompromised patients. Incidence or duration of infection in chronic norovirus infections did not differ between genotypes, suggesting host-mediated susceptibility. [ABSTRACT FROM AUTHOR]

Human noroviruses are the leading causative agents of epidemic and sporadic viral gastroenteritis and childhood diarrhoea worldwide. Human histo-blood group antigens (HBGA) serve as receptors for norovirus capsid protein attachment and play a critical role in infection. This makes HBGA-norovirus binding a promising target for drug development. Recently solved crystal structures of norovirus bound to HBGA have provided a structural basis for identification of potential anti-norovirus drugs and subsequently performed in silico and in vitro drug screens have identified compounds that block norovirus binding and may thereby serve as structural templates for design of therapeutic norovirus inhibitors. This review explores norovirus therapeutic options based on the strategy of blocking norovirus-HBGA binding. [ABSTRACT FROM AUTHOR]

The global health community is beginning to gain an understanding of the global burden of norovirus-associated disease, which appears to have significant burden in both developed- and developing-country populations. Of particular importance is the growing recognition of norovirus as a leading cause of gastroenteritis and diarrhea in countries where rotavirus vaccine has been introduced. While not as severe as rotavirus disease, the sheer number of norovirus infections not limited to early childhood makes norovirus a formidable global health problem. This article provides a landscape review of norovirus vaccine development efforts. Multiple vaccine strategies, mostly relying on virus-like particle antigens, are under development and have demonstrated proof of efficacy in human challenge studies. Several are entering phase 2 clinical development. Norovirus vaccine development challenges include, but are not limited to: valency, induction of adequate immune responses in pediatric and elderly populations, and potential for vaccine-strain mismatch. Given current strategies and global health interest, the outlook for a norovirus vaccine is promising. Because a norovirus vaccine is expected to have a dual market in both developed and developing countries, there would likely be scale-up advantages for commercial development and global distribution. Combination with or expression by another enteric pathogen, such as rotavirus, could also enhance uptake of a norovirus vaccine. [ABSTRACT FROM AUTHOR]