Search Results (175)

Objectives: Norovirus outbreaks occur in densely populated environments, such as long-term care facilities, hospitals, and schools. On 22 October 2022, an outbreak of acute gastroenteritis was reported at a kindergarten in Korea. An epidemiologic investigation was conducted to identify the source of the infection and prevent further spread. Methods: Rectal swab and environmental samples were collected for bacterial and viral testing. A retrospective cohort study was conducted among 114 kindergarteners at the kindergarten. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated to assess associations of contact with the primary case, as well as food and water consumption. Results: Of the kindergarteners, 28 out of 114 (24.6%) met the case definition. The primary case occurred on 19 October, and subsequent cases began on 21 October. Sharing the same four-year-old class as the primary case (RR, 2.56; 95% CI, 1.35–4.87), being in the same regular class (RR, 2.37; 95% CI, 1.27–4.41), being on the same floor during after-school class (RR, 3.49; 95% CI, 1.74–7.00), and attending the same English class (RR, 1.98; 95% CI, 1.05–3.72) were statistically significant. Consumption of drinking water on the third floor and fourth floor on 20 October had significantly higher and lower RRs, respectively. Norovirus was detected in 9 out of 18 rectal swab samples (50.0%). Conclusions: This norovirus outbreak at the kindergarten was presumed to have been caused by person-to-person transmission from the primary case. Isolation and restriction of symptomatic children in kindergartens should be thoroughly implemented. Additionally, enhanced surveillance among family members of affected individuals is necessary to prevent further outbreaks. Full article

Background/Objectives: Norovirus is a major cause of acute gastroenteritis worldwide. Considering its highly infectious and transmissible nature, rapid and accurate diagnostic tools are of utmost importance for the effective control of outbreaks in the context of point-of-care testing (POCT). In this study, we developed a genogroup-specific multiplex reverse transcriptase loop-mediated isothermal amplification assay to detect the human norovirus genogroups I and II (GI and GII, respectively). Methods: For the comprehensive detection of clinically relevant genotypes, two sets of primers were incorporated into the assays targeting the RdRp-VP1 junction: one against GI.1 and GI.3, and the other for GII.2 and GII.4. Following optimization of the reaction variables, we standardized the reaction conditions at 65 °C with 6 mM MgSO₄, 1.4 mM dNTPs, 7.5 U WarmStart RTx Reverse Transcriptase, and Bst DNA polymerase at 8 U and 10 U for GI and GII, respectively. Amplification was monitored in real-time using a thermocycler platform to ensure precise quantification and detection. Finally, the assay was evaluated through portable isothermal detection device to test its feasibility in on-site settings. Results: Both assays detected the template down to 10²–10³ copies per reaction and showed high target selectivity, yielding no non-specific amplification across 39 enteric pathogens. These assays enabled prompt detection of GI within 10–12 min and of GII within 12–17 min after the reaction was initiated. Onsite validation reveals all template detection below 15 min, demonstrating its potential feasibility in point-of-care applications. Including the sample preparation time, test results were obtained in less than 1 h. Conclusions: This method is a rapid, reliable, and scalable solution for detecting human norovirus in POCT settings for both clinical diagnosis and public health surveillance. Full article

Background: Acute viral gastroenteritis (AVG) still has an impact on children under 5 years old in developing countries. In Romania, vaccination against Rotavirus is not included in the National Immunization Program. Children from poor social backgrounds represent 48% of the patients hospitalized in Children’s Clinical Hospital of Brasov. The use of antibiotics in Romania is high. Methods: The retrospective study enrolled 1054 children, 0–48 months of age, hospitalized in the Emergency Clinical Hospital for Children Brasov between January 2022–December 2023, for Rotavirus, Adenovirus or Norovirus acute gastroenteritis. Children presenting nosocomial infections were excluded. All children that have met the previously mentioned criteria, presenting positive stool samples (immunochromatography method) for Rotavirus, Adenovirus or Norovirus were included in the study. Results: Out of 1054 cases of AVG 782 (74.2%) were due to Rotavirus, 196 (18.5%) to Adenovirus and 76 (7.3%) to Norovirus. A total of 477 (45.3%) patients came from poor social backgrounds and 577 (54.7%) children from good social backgrounds. Rotavirus infection was equally prevalent in both groups (p < 0.35). Children from poor social backgrounds presented an average age of 11 months (SD ± 9; range 14 days–48 months) and a hospitalization average of 5.86 days (SD ± 3.67; range 1–22 days) compared to the others, who presented an average of 21 months (SD ± 15; range 26 days–48 months) and hospitalization average of 5.20 days (SD ± 2.51; range 1–18 days) (p < 0.01; p < 0.01). Severe dehydration presented 267 children from poor settings (56%) and 186 (17.6%) received antibiotics, compared to the other group—224 children (38.8%) with severe dehydration and 216 (20.4%) receiving antibiotics. The most used antibiotic for both groups was Ceftriaxone (53.9% and 57.6% of all AVG). Conclusions: Rotavirus is the leading AVG cause. Children from poor backgrounds were younger, more dehydrated, hospitalized longer. Full article

Norovirus (NoV), a leading cause of acute gastroenteritis worldwide, imposes significant morbidity and economic burdens across all age groups. Timely and accurate laboratory diagnosis is crucial for effective outbreak control and patient management. However, current diagnostic methods often require specialized equipment, technical expertise, and considerable time. To address these challenges, we developed a visual detection method utilizing gold nanoparticles (AuNPs) functionalized with the SMV25 aptamer specific to the NoV capsid protein. Detection relies on MgCl₂-induced changes in the color and absorbance of these aptamer-functionalized AuNPs. The assay exhibited a good linear relationship between the A630/A520 absorbance ratio and NoV capsid protein concentration. Specifically, in a buffer system, this linearity (R² = 0.9026) was observed over a 0–32 ng/µL range with a limit of detection (LOD) of 9.65 ng/µL. Similarly, for NoV spiked into stool suspensions, a strong linear correlation (R² = 0.9170) was found across a 0–100 ng/µL range, with an LOD of 37.11 ng/µL. Evaluation with real stool samples yielded 77% sensitivity and 65% specificity. Notably, the assay demonstrated the highest sensitivity towards NoV GII.2 (100%), followed by GII.4 (78%). Scanning transmission electron microscopy confirmed the underlying aggregation and dispersion patterns of the aptamer-functionalized AuNPs. This colorimetric assay provides a simple, rapid, and visual method for NoV detection. Nevertheless, further enhancements are necessary to improve its performance in the direct testing of complex specimens, paving the way for future on-site detection applications, especially in resource-limited settings. Full article

Human noroviruses (HuNoVs) are the primary cause of acute viral gastroenteritis. There are no antivirals or vaccines available to treat and/or prevent HuNoV. Norovirus 3C-like protease (3CLpro) is essential for viral replication; consequently, the inhibition of this enzyme is a fruitful avenue for antinorovirus therapeutics. To discover novel 3CLpro inhibitors with diverse scaffolds, a multi-stage virtual screening approach was performed by docking >10 million compounds into the 3CLpro catalytic site. An initial subset of 18 compounds was selected, and compounds YY-1029 and YY-4204 were identified as the best two molecules. Molecular dynamics (MD) simulations and binding free energy calculations (MM/GBSA) of YY-1029 and YY-4204 were performed to elucidate the binding mechanisms. The ADMET properties were also estimated to predict the potential druggability of representative molecules. All 18 compounds were evaluated for their antinorovirus activity and cytotoxicity in a cell-based replicon system. This work could provide information for the development of 3CL pro inhibitors. Full article

Norovirus, a major cause of acute gastroenteritis, possesses a single-stranded positive-sense RNA genome. The viral 3C-like cysteine protease (3CL^pro) plays a critical role in processing the viral polyprotein into mature non-structural proteins, a step essential for viral replication. Targeting 3CL^pro has emerged as a promising strategy for developing small-molecule inhibitors against Norovirus. In this study, we employed a combination of virtual screening and the FlipGFP assay to identify potential inhibitors targeting the 3CL^pro of Norovirus genotype GII.4. A library of approximately 58,800 compounds was screened using AutoDock Vina tool, yielding 20 candidate compounds based on their Max Affinity scores. These compounds were subsequently evaluated using a cell-based FlipGFP assay. Among them, eight compounds demonstrated significant inhibitory activity against 3CL^pro, with Gedatolisib showing the most potent effect (IC₅₀ = 0.06 ± 0.01 μM). Molecular docking and molecular dynamics simulations were conducted to explore the binding mechanisms and structural stability of the inhibitor–3CL^pro complexes. Our findings provide valuable insights into the development of antiviral drugs targeting Norovirus 3CL^pro, offering potential therapeutic strategies to combat Norovirus infections. Full article

Norovirus is a leading cause of viral gastroenteritis worldwide and has been studied extensively from the perspective of life and biomedical sciences. However, no biothermodynamic analysis of Norovirus has been reported in the literature. Such an analysis would provide insights into the role of energetic constraints in the interactions between Norovirus and its host cells and other viruses. In this research, Norovirus was characterized from the aspect of chemistry and chemical thermodynamics, with the determination of its molecular formula, empirical formula, molar mass and thermodynamic properties (enthalpy, entropy, Gibbs energy) of formation. Based on these properties, biosynthesis reactions were formulated that show how Norovirus particles are synthetized inside host cells, and the thermodynamic properties of biosynthesis were determined. Moreover, the thermodynamic properties of the binding of Norovirus to its host cell receptor were determined. These were then used to develop a model of virus–host interactions at the cell membrane (antigen-receptor binding) and inside the cytoplasm (virus multiplication), with the phenomenological equations of nonequilibrium thermodynamics. Based on the model, an analysis of the virus–virus competition between Norovirus and Rotavirus was conducted. Full article

Acute gastroenteritis (AGE) has one of the highest rates of morbidity and mortality among children under five years old worldwide. It is estimated that 1.7 billion cases of childhood diarrheal diseases occur annually, leading to up to 443,832 deaths. Approximately 90% of these cases are viral, with human norovirus being the main cause in countries that have implemented rotavirus vaccines. The objective of this study was to describe the prevalence and genetic diversity of norovirus in child outpatients and inpatients under five years old at the Regional Hospital of Antofagasta. From 1 January to 31 October 2019, a total of 121 stool samples were collected to detect the presence of norovirus GI and GII using Taqman™-based real-time RT-PCR. Norovirus RNA was detected in 50 (41.3%) samples, of which 96% were typed as GII.4 Sydney (42% GII.4 Sydney[P16] and 54% GII.4 Sydney[P4 New Orleans]). Furthermore, most (92%) of the positive specimens were from children under two years of age and a majority were detected in April (38%) and May (20%). Our findings highlight the high burden of norovirus in hospitalized children with AGE and the importance of molecular strain surveillance to support vaccine development. Full article

Background/Objective: Acute gastroenteritis is a major cause of diarrheal illnesses throughout the United States. The purpose of this article is to review the current knowledge in diagnostic and therapeutic aspects. Methods: A comprehensive literature review was conducted using PubMed and Google Scholar, focusing on articles published within the last ten years. Results: There are multiple etiologies of gastroenteritis that affect the general population. Out of the many causes, norovirus continues to be a leading cause of acute diarrheal illness worldwide. Rotavirus was also a common form of diarrhea worldwide, but the development of routine vaccination has largely reduced its incidence. Bacterial gastroenteritis continues to be a significant burden on healthcare facilities worldwide. Supportive care remains the cornerstone of treatment, while using antibiotics remains crucial in severe bacterial forms of gastroenteritis. Conclusions: Acute gastroenteritis remains a significant global health concern requiring a multifaceted approach for effective management. Enhanced diagnostic techniques, vaccine development, and robust public health measures are essential in controlling the spread of gastroenteritis. Full article

Background and objectives: Acute gastroenteritis (AGE) remains a significant cause of morbidity in children, particularly in low- and middle-income countries. Viral pathogens, including rotavirus (RoV), norovirus (NoV), and adenovirus (HAdV), are among the leading causes of AGE. This study aimed to determine the prevalence of viral, bacterial, and parasitic enteric pathogens associated with AGE among hospitalized children in Northern Jordan. Materials and Methods: A total of 195 stool samples were collected from hospitalized children with AGE during the winter seasons of 2022–2024. Multiplex real-time qPCR assays were performed to detect common pathogens. The prevalence of each pathogen was determined, and co-infections were analyzed. Clinical symptoms, demographic characteristics, and associations between specific pathogens and disease severity were evaluated. Results: Viral pathogens were the predominant cause of AGE, with NoV detected in 53 cases (27.2%; of which 19.0% were NoV GI and 8.2% NoV GII), followed by RoV (24.1%), HAdV (20.0%), HAstV (13.3%), and SaV (12.3%). Co-infections were observed in several cases, particularly among viral infections evoked by RoV, HAdV, and NoV GI. Bacterial and parasitic infections were less prevalent, with Salmonella and Campylobacter spp. detected in 23.1% and 13.8%, respectively. Additionally, Cryptosporidium was identified in two cases (0.5%). Conclusions: Viral pathogens, particularly NoV, RoV, and HAdV, are the leading causes of AGE among hospitalized children in Jordan. Co-infections among viral pathogens were common, whereas bacterial and parasitic infections played a limited role in the disease burden. These findings emphasize the importance of continued surveillance and vaccination efforts, particularly for RoV, to reduce AGE-related hospitalizations in children. Full article

At present, there is no research that classifies the epidemic intensity of acute gastroenteritis (AGE) caused by Norovirus (NoV) GII combined cases and environmental surveillance data at the same time. With reference to the experience of the epidemiological-level classification of infectious disease and the actual epidemiological status of NoV AGE in Chaoyang District, Beijing, China, the epidemic intensity of NoV GII was divided into five grades with increasing intensity from grade 1 to grade 5, which corresponds to non-epidemic risk, general risk, moderate risk, high risk, and ultra-high risk, respectively. If the synthetic index of two consecutive monitoring weeks in the epidemic season of 2023–2024 exceeds a certain threshold, an early warning for the corresponding epidemic intensity will be issued and recommendations on the corresponding control measures will be given. This study established and quantified the criteria for the epidemic intensity of AGE caused by NoV GII based on case surveillance data and environmental surveillance data. It provides a reference for other methods to carry out relevant studies in the future. However, mathematical models cannot completely replace skilled experience. Therefore, when making decisions with early warning models in practice, it is necessary to refer to the opinions of professional and experienced experts to avoid the bias of the early warning model from affecting strategy judgment. Full article

Globally, norovirus has become the primary cause of outbreaks of acute gastroenteritis, and an increasing number of norovirus GII infections have been associated with shellfish. This highlights the urgent need to establish sensitive and rapid detection platforms for timely screening of contaminated shellfish to reduce the risk of virus transmission. To address this challenge, we developed a novel detection method combining multienzyme isothermal rapid amplification (MIRA) with qPCR, referred to as MIRA–qPCR, specifically targeting norovirus GII. It exhibited robust specificity, demonstrating no cross-reactivity with sapovirus, rotavirus, hepatitis A virus, Escherichia coli, Listeria monocytogenes, or Vibrio parahaemolyticus, and exhibited high sensitivity, detecting as low as 1.62 copies/μL for recombinant plasmid standards. Furthermore, MIRA–qPCR showed good linearity in the 1.62 × 10¹ to 1.62 × 10⁷ copies/μL range, with an R² > 0.90. MIRA–qPCR and qPCR assays were performed on 125 fresh shellfish samples; there was good consistency in the detection results, and the Kappa value was 0.90 (p < 0.001). The sensitivity and specificity of the MIRA–qPCR detection were 100.00% and 97.25%, respectively. The MIRA–qPCR technique provides a viable alternative for the rapid screening of norovirus GII-contaminated shellfish to guarantee food safety. Full article

Noroviruses are a major cause of acute gastroenteritis, often transmitted through contaminated food and water. In this study, lemon juice (LJ), rich in citric acid (CA) and flavonoids, was tested against Feline Calicivirus (FCV), used as a surrogate of human norovirus. Significant virucidal activity was observed for pure LJ (pH = 2.3), with a reduction in viral titers as high as 4.50 log₁₀ TCID₅₀/50 µL after 30 s and complete inactivation after 1 min. LJ also showed limited virucidal activity at a dilution of 1:2000 (pH = 6.7), with a reduction in viral titer of 0.75 log₁₀ TCID₅₀/50 µL. CA (at the same molarity as CA in pure LJ and adjusted to pH = 2.3) exhibited virucidal effects comparable to pure LJ, with a decrease in viral titers as high as 3.75 log₁₀ TCID₅₀/50 µL, whilst diluted CA (pH = 6.7) did not show significant effects. This study demonstrated the virucidal efficacy of LJ, suggesting the role of pH and, eventually, of LJ bioactive compounds against a norovirus surrogate. Due to its large use in food preparation, LJ has the potential to enhance the safety of raw food. Also, broader applications in personal hygiene and surface disinfection could be devised. Full article

Norovirus is a major etiological agent of nonbacterial gastroenteritis around the world. Due to its in vitro culture complexity, high genome diversity, and the lack of cross-reactive immunity between genogroups, there is an unmet urgent need for polyvalent norovirus vaccines that provide broad-spectrum protection, and no vaccine has gained global approval to date. In this study, we constructed a bivalent norovirus vaccine, based on the highly attenuated poxvirus [strain VG9] vector, expressing the major capsid protein VP1 from genotypes GII.4 and GII.17. VG9-NOR exhibited a comparable replication ability to the authentic virus while preserving good safety. After the intramuscular and intranasal immunization of mice, VG9-NOR induced high IgG- and IgA-binding antibody (Ab) titers against GII.4 and GII.17, increased the secretion of GII.4 and GII.17-specific HGBA-blocking antibodies, and enhanced GII.17-specific mucosal immunity. Furthermore, VG9-NOR also induced a Th1-mediated cellular response. These results demonstrate that the polyvalent poxvirus vector vaccine expressing VP1 variants from different subtypes is able to elicit effective protection. Our study highlights the VG9 vector as a highly promising candidate for the development of polyvalent norovirus vaccines. Full article

Human norovirus (HuNoV) is a major causative agent of foodborne illness and causes acute viral gastroenteritis. This study aimed to compare the virucidal efficacies of alcohol-based disinfectants against HuNoV and its surrogates for murine norovirus and feline calicivirus using a cell culture infectivity assay. Additionally, the study evaluated the validity of estimating virucidal efficacy on HuNoV from the results of virucidal efficacy on the surrogate virus. All disinfectants decreased the titer of each virus by >3 log₁₀ and >4 log₁₀ for an exposure duration of 30 s against murine norovirus and feline calicivirus, respectively. However, acidic alcohol-based disinfectants completely inactivated the HuNoV GII.17 strain for 30 or 60 s, whereas an alkaline alcohol-based disinfectant did not inactivate HuNoV GII.17 for 60 s. This finding indicates that the pH of alcohol disinfectants affects their virucidal effects against HuNoV, and acidity has a higher virucidal efficacy against HuNoV than alkalinity. Disinfectants showing virucidal efficacy against surrogates were not effective against HuNoV. Few studies have used cell culture infectivity assays to test the inactivating effects of hand sanitizers on HuNoV and its surrogates. Our study provides useful information for the development of disinfectants that are effective against HuNoV. Full article