Norovirus In Stool Samples Research Articles

Norovirus outbreaks due to contaminated drinking water and probable person-to-person transmission, Kerala, India, 2021

BackgroundIn July 2021, the Alappuzha district in Kerala, India, reported an unexpected number of acute gastroenteritis (772) cases (Outbreak A). On October 10, 2021, a university in Wayanad, Kerala, reported 25 acute gastroenteritis cases (Outbreak B). We described both the outbreaks and determined the agent, source and risk factors. MethodsWe defined a suspected case as the occurrence of vomiting or at least three episodes of loose stools within 24hours and a confirmed case as those with stool samples/rectal swabs positive for norovirus. We did a matched case-control study in Outbreak A and a retrospective cohort study in Outbreak B. We calculated the adjusted odds ratio (aOR) in outbreak A, relative risk (aRR) in outbreak B and population attributable fraction (PAF). We tested stool and water samples for bacteria and viruses. ResultsWe identified Group II norovirus in stool samples in both outbreaks and 4/5 water samples in Outbreak A. Suspected norovirus infection was associated with drinking inadequately boiled water from the municipal water supply in outbreak A [aOR: 4.5; 95% C.I: 1.2-15.8; PAF: 0.23] and well water in hostels in outbreak B [aRR: 2.2; 95% C.I: 1.2-3.9; PAF: 0.15]. In Outbreak A, groundwater from tube wells was mixed in the municipal water supply overhead tanks without chlorination. ConclusionThe gastroenteritis outbreaks were caused by Group II norovirus due to the consumption of inadequately boiled contaminated groundwater (outbreak A) and well water (outbreak B). We recommended superchlorination of overhead tanks and wells and boiled water for drinking.

A "peptide-target-aptamer" electrochemical biosensor for norovirus detection using a black phosphorous nanosheet@Ti3C2-Mxene nanohybrid and magnetic covalent organic framework.

Norovirus (NoV) is a major foodborne pathogen responsible for acute gastroenteritis epidemics, and establishing a robust detection method for the timely identification and monitoring of NoV contamination is of great significance. In this study, a peptide-target-aptamer sandwich electrochemical biosensor for NoV was fabricated using Au@BP@Ti3C2-MXene and magnetic Au@ZnFe2O4@COF nanocomposites. The response currents of the electrochemical biosensor were proportional to the NoV concentrations ranging from 0.01-105 copies/mL with a detection limit (LOD) of 0.003 copies/mL (S/N=3). To our best knowledge, this LOD was the lowest among published assays to date, due to the specific recognition of the affinity peptide and aptamer for NoV and the outstanding catalytic activity of nanomaterials. Furthermore, the biosensor showed excellent selectivity, anti-interference performance, and satisfactory stability. The NoV concentrations in simulative food matrixes were successfully detected using the constructed biosensor. Meanwhile, NoV in stool samples was also successfully quantified without complex pretreatment. The designed biosensor had the potential to detect NoV (even at a low level) in foods, clinical samples, and environmental samples, providing a new method for NoV detection in food safety and diagnosing foodborne pathogens.

Facile and foldable point-of-care biochip for nucleic acid based-colorimetric detection of murine norovirus in fecal samples using G-quadruplex and graphene oxide coated microbeads

Norovirus is one of the most common causes of gastroenteritis, a disease characterized by diarrhea, vomiting, and stomach pain. A rapid on-site identification of the virus from fecal samples of patients is a prerequisite for accurate medical management. Here, we demonstrate a rapid nucleic acid-based detection platform as an on-site biosensing tool that can concentrate viruses from fecal samples. Moreover, it can perform RNA extraction and identification, and signal amplification using G-quadruplex and hemin containing DNA probes (G-DNA probes) and graphene oxide (GO)-coated microbeads. Briefly, murine noroviruses are lysed without chemicals on the surface of the GO microbeads. Subsequently, the target RNA is hybridized with G-DNA probes, and the resultant RNA/G-DNA probe complex is separated from unbound G-DNA probes using GO beads and is mixed with the detection buffer (ABTS/H2O2). Presence of murine noroviruses causes a colorimetric change of the buffer from colorless to green. Thus, we integrated all processes required to detect murine noroviruses in stool samples in a simple foldable microfluidic chip. Moreover, it can detect 101 pfu of the virus in 30 min in a fecal sample.

Prevalence and Genetic Diversity of Norovirus in Acute Gastroenteritis Cases in the Southwest Province of Turkey.

Aims:Noroviruses may cause both epidemic and sporadic acute gastroenteritis globally. Thus, this study evaluated the prevalence of norovirus in stool samples of hospitalized patients with acute gastroenteritis in Aydin, Turkey using enzyme-linked immunoassay (ELISA) and real-time reverse transcription-polymerase chain reaction (rRT-PCR) and genotyped positive samples to detect which genotypes have currently circulated.Methods:This retrospective descriptive study collected 92 stool samples from patients with acute gastroenteritis symptoms from Aydın Adnan Menderes University Hospital from September 2017 to May 2019. The samples were tested using the commercial Third Generation Ridascreen norovirus ELISA and rRT-PCR. Positive samples were genotyped by sequencing of conventional positive RT-PCR products followed by phylogenetic analysis.Results:Of the 92 samples, 5 (5.4%) using ELISA and 12 (13%) using rRT-PCR tested positive for norovirus. All positive samples were genogroup II (GII). Two norovirus positive samples were genotyped successfully using DNA sequencing of the nested conventional PCR products. One sample (GII/Hu/TR/2019/Aydin25) could be categorized as GII.3 and the other (GII/Hu/TR/2019/Aydin20) as GII.13.Conclusion:rRT-PCR testing of stool samples is more sensitive than Ridascreen ELISA. Data from our study provide protocols for how to study norovirus epidemiology.

Detection of Norovirus in stool samples by RT-PCR from under five years age children hospitalized for acute gastroenteritis in Basrah, Iraq

Detection of Norovirus in stool samples by RT-PCR from under five years age children hospitalized for acute gastroenteritis in Basrah, Iraq

Multicenter evaluation of the revised RIDA® QUICK test (N1402) for rapid detection of norovirus in a diagnostic laboratory setting

The updated RIDA® QUICK (N1402) immunochromatographic assay (R-Biopharm) for detection of norovirus was evaluated during a prospective, multicenter study using 771 stool samples from patients with gastroenteritis. Compared to real-time reverse transcriptase polymerase chain reaction (RT-rtPCR) as gold standard, the RIDA® QUICK had an overall sensitivity of 72.8% (91/125) and a specificity of 99.5% (640/643). Genotype analysis of the polymerase (ORF1) and capsid (ORF2) region of the genome indicated that the RIDA® QUICK assay could detect a broad range of genotypes including new variants (15 of 125 positive samples) which were detected by an in-house SYBR®Green RT-rtPCR, but not by the RIDA® GENE PCR PG1415 (R-Biopharm) and mostly not by the RIDA® GENE PCR PG1405 and the Xpert® Norovirus assay (Cepheid). The RIDA® QUICK can be used to reliably confirm norovirus in stool samples, but a negative result does not definitively exclude the presence of norovirus.

Evaluation of immunochromatographic tests for the rapid detection of the emerging GII.17 norovirus in stool samples, January 2016

A novel GII.17 norovirus emerged in Asia in the winter of 2014/15. A worldwide spread is conceivable and norovirus diagnostic assays need to be evaluated to investigate if they adequately detect this emerging genotype. Seven immunochromatographic kits commercially available in Europe were evaluated on ten stool samples where GII.17 virus had been quantified by real-time reverse transcription-polymerase chain reaction. All the kits detected GII.17 with various sensitivities, partly depending on the virus titre.

Detection of Norovirus in stool samples by RT-PCR from under five years age children hospitalized for acute gastroenteritis in Basrah, Iraq

Human noroviruses are the leading cause of non-bacterial gastroenteritis in children worldwide. The objectives of this study are to determine the frequency and importance of norovirus in diarrheal illness among children below 5 years of age and to investigate the most affected age, seasonal distribution and the major clinical symptoms associated with norovirus infections; 400 stool samples (200 symptomatic cases and 200 asymptomatic healthy children) were investigated during the period from March 2011 to March 2012.Norovirus was detected in 8% of symptomatic children whereas all the control groups were norovirus negative. Norovirus was highly prevalent among children of 18-23 months of age (P=0.05). Noroviruses were continuously detected throughout the year except in May and October, but the principle peaks of detection were in November. The most common clinical symptoms beside diarrhea observed among norovirus infected children were vomiting (94%), fever (69%), dehydration (50%) and abdominal pain found in 31%.

Characteristics of norovirus infection in Serbia.

Norovirus (NoV), formerly Norwalk-like virus is the most common cause of acute gastroenteritis in humans of all ages. It is known that 90% of viral gastroenteritis and about 60-85% of all outbreaks of gastroenteritis, especially in the territory of United States of America, Europe and Japan are caused by this virus. For the countries of the northern hemisphere, individual cases and outbreaks of acute NoV gastroen teritis appear in seasonal pattern, mainly during the winter months. The aim of this study as to describe characteristics of acute gastroenteritis with the established NoV etiology in Serbia. The study group included 88 patients with the symp toms of acute gastroenteritis, throughout the year 2010 and 2011. From all the patients, stool samples were taken less than three days from the onset of symptoms. Detection of NoV in stool samples was performed by commercial qualitative immunochromatography assay. Statistical analysis included application of x2 test, Mann-Whitney U-test, Kruskal-Wallis's test, Spearman's rank correlation test and logistic regression analysis. Outbreaks of acute gastroenteritis caused by NoV were recorded to be the most common in children with the incidence of infection of 50% in the age group 0-15 years. Analysis of individual symptoms in the NoV proven infection, showed that diarrhea was the most common symptom, followed by vomiting espe cially in small children, while abdominal pain was most common in elderly (> 65 years). The presence of frequent vomiting, more than 4 times/day, indicated NoV infection in the women, while for men the infection was always presented with diarrhea. The obtained results confirmed that small children and elderly are,the most susceptible to NoV infection and that outbreaks are more frequent in the winter months. Those who consumed food in restaurants and other public facilities were not at higher risk for NoV infection.

Mapping broadly reactive norovirus genogroup I and II monoclonal antibodies.

Noroviruses are responsible for most acute nonbacterial epidemic outbreaks of gastroenteritis worldwide. To develop cross-reactive monoclonal antibodies (MAbs) for rapid identification of genogroup I and II (GI and GII) noroviruses (NoVs) in field specimens, mice were immunized with baculovirus-expressed recombinant virus-like particles (VLPs) corresponding to NoVs. Nine MAbs against the capsid protein were identified that detected both GI and GII NoV VLPs. These MAbs were tested in competition enzyme-linked immunosorbent assays (ELISAs) to identify common epitope reactivities to GI and GII VLPs. Patterns of competitive reactivity placed these MAbs into two epitope groups (groups 1 and 2). Epitopes for MAbs NV23 and NS22 (group 1) and MAb F120 (group 2) were mapped to a continuous region in the C-terminal P1 subdomain of the capsid protein. This domain is within regions previously defined to contain cross-reactive epitopes in GI and GII viruses, suggesting that common epitopes are clustered within the P1 domain of the capsid protein. Further characterization in an accompanying paper (B. Kou et al., Clin Vaccine Immunol 22:160-167, 2015, http://dx.doi.org/10.1128/CVI.00519-14) revealed that MAb NV23 (epitope group 1) is able to detect GI and GII viruses in stool. Inclusion of the GI and GII cross-reactive MAb NV23 in antigen detection assays may facilitate the identification of GI and GII human noroviruses in stool samples as causative agents of outbreaks and sporadic cases of gastroenteritis worldwide.

Lessons from Norovirus Outbreak in Warsaw, Poland, December 2012

Efficient foodborne outbreak investigations are important for identification of gaps in food safety and public health practice. This article reports on an investigation of a gastroenteritis outbreak linked to catering food following a Christmas reception at the National Institute of Public Health-National Institute of Hygiene (NIPH-NIH) in Warsaw in December 2012. Of 192 employees eating food at the catering event, 97 (50.5 %) developed symptoms. Persons eating dishes with recipes containing frozen carrots were five times more likely to develop gastrointestinal symptoms compared to those who did not eat carrots. Laboratory analysis identified norovirus in stool samples taken from symptomatic persons. Leftover food was not available for testing. The investigators did not collect stool specimens from food handlers and did not conduct trace backs for the suspected food ingredients. This investigation underlines the need for a revision of an existing procedures and importance of their complementation with detailed instructions for the local public health authorities for effective completion of foodborne outbreaks investigations in Poland.

Detection of Noroviruses Isolated From Children With Acute Gastroenteritis by Rt-PCR in Iran

Background: Noroviruses are one of the major viral pathogens responsible for gastroenteritis. Outbreaks of diarrhea due to Norovirus have been reported frequently. This study is performed to determine the prevalence of Norovirus in fecal specimens of children with gastroenteritis. Many viruses can cause gastroenteritis, including Rotaviruses; Adenoviruses types 40 and 41; Sapoviruses; and Noroviruses. Current techniques used for detection of Noroviruses in stool samples include multi-step viral RNA extraction and purification followed by reverse transcriptase-polymerase chain reaction (Rt-PCR). Objectives: The purpose of this study is to detect Norovirus in stool samples by Rt-PCR in 5 different centers in Iran. Patients and Methods: In this study, 2,170 stool samples were collected from children less than five years old from five different cities, all of whom had acute gastroenteritis. Detection of Noroviruses was performed through Rt-PCR. The mean age of the studied population was 48 months. Fecal specimens were collected within 24 hours of admission. The specimens were frozen, sent to the laboratory, and then stored at -70° C until being tested for Norovirus. Results: Rt-PCR was performed for 2,170 stool samples containing 90 (4.14%) Norovirus positive (0.97% Tehran, 0.64% Tabriz, 0.18% Mashhad, 1.57% Shiraz, 0.78% Bandar Abbas). The RT-PCR was validated with published primers for Norovirus (JV12/JV13). In both retrospective and prospective settings, the Rt-PCR was equally sensitive (95%) and specific (95%) in detecting Norovirus. Conclusions: Noroviruses, which are important human pathogens, may cause epidemic acute viral gastroenteritis which in turn can be easily detected by molecular methods.

The validation and utility of a quantitative one-step multiplex RT real-time PCR targeting Rotavirus A and Norovirus

Rotavirus (RoV) and Norovirus (NoV) are the main causes of viral gastroenteritis. Currently, there is no validated multiplex real-time PCR that can detect and quantify RoV and NoV simultaneously. The aim of the study was to develop, validate, and internally control a multiplex one-step RT real-time PCR to detect and quantify RoV and NoV in stool samples. PCR sensitivity was assessed by comparing amplification against the current gold standard, enzyme immunoassay (EIA), on stool samples from 94 individuals with diarrhea and 94 individuals without diarrhea. PCR detected 10% more RoV positive samples than EIA in stools samples from patients with diarrhea. PCR detected 23% more NoV genogroup II positive samples from individuals with diarrhea and 9% more from individuals without diarrhea than EIA, respectively. Genotyping of the PCR positive/EIA negative samples suggested the higher rate of PCR positivity, in comparison to EIA, was due to increased sensitivity, rather than nonspecific hybridization. Quantitation demonstrated that the viral loads of RoV and NoV in the stools of diarrheal patients were an order of magnitude greater than in individuals without diarrhea. This internally controlled real-time PCR method is robust, exhibits a high degree of reproducibility, and may have a greater utility and sensitivity than commercial EIA kits.

Detection of norovirus in stool samples by RT-PCR in 5 disease centers in Iran

Background Noroviruses are a group of viruses that cause gastroenteritis (illness that usually includes diarrhea and/or vomiting) in people. Gastroenteritis means inflammation of the stomach and small and large intestines. Many different viruses can cause gastroenteritis, including rotaviruses; noroviruses; adenoviruses, types 40 and 41; sapoviruses; and astroviruses. Current techniques used for detection of noroviruses in stool samples include multi-step viral RNA extraction and purification followed by reverse transcriptase-polymerase chain reaction (RT-PCR). The aim of this study is the detection of norovirus in stool samples by RT-PCR in 5 disease centers in Iran.

Assessment of a rapid immunochromatographic test for the diagnosis of norovirus gastroenteritis

Noroviruses are the leading cause of acute gastroenteritis in people of all ages. Since the viruses are highly infectious, rapid and early diagnosis is important to prevent and control the disease. The present study aimed to evaluate the commercial immunochromatographic test RIDA® QUICK Norovirus for the detection of norovirus in stool samples from patients with acute gastroenteritis in Thailand. As compared with reference RT-PCR results, the RIDA® QUICK Norovirus assay provided a sensitivity of 48.2 and 83.3% with a specificity of 87.5%. False positive results were observed in 12.5% of norovirus-negative stool samples. Based on commercial quantitative real-time RT-PCR, the RIDA® QUICK Norovirus assay revealed a highly significant association, p-value <0.001, and good agreement (kappa = 0.6). The assay could detect norovirus in stool samples ranging from 3.22 × 10(6) to 3.26 × 10(8) copies/ml. False negative results occurred in the stool samples containing 5.9 × 10(6) copies/ml of norovirus GI or 1.85 × 10(4) - 4.28 × 10(5) copies/ml of GII. The immunochromatographic RIDA® QUICK Norovirus assay may be useful for rapid screening of norovirus infections in patients with acute gastroenteritis in both developed and developing countries where the RT-PCR method has not been established for routine diagnosis.

Evaluation of a new commercial assay for the detection of norovirus in stool samples

Noroviruses are important human pathogens causing acute gastroenteritis; they can hardly be propagated in any cell culture system and are often difficult to visualize by using electron microscopy (ME). These aspects, as well as the need of an accurate diagnosis justify the development of a number of rapid diagnostic methods aimed at improving the identification of noroviruses and based on the research of viral genomic sequences or, alternatively, of norovirus specific proteins. In this study 60 stool samples were analyzed by traditional techniques, such as cell culture (MT), and by rapid methods like ME and nested reverse transcriptase-polimerase chain reaction (nRT-PCR).A third rapid test, the immunochromatographic assay RIDA ®QUICK Norovirus (R-Biopharm) for the research of norovirus proteins (belonging to genogroups I and II), was used retrospectively on the same samples stored at -80°C. The results obtained by using nRT-PCR (i.e. the most sensitive method) and the immunochromatographic assay were compared, showing that 39 samples were positive and 21 negative in nRT-PCR, while only 28 (71.8%) were positive with the immunochromatographic assay; among the negative samples, one resulted positive with RIDA ®QUICK Norovirus. The latter test proved to be appreciably sensitive, even if nRT-PCR still remains the gold standard method for the laboratory diagnosis of norovirus. Nevertheless, the easy-to-use and cheaper immunochromatographic assay can be usefully applied as a screening test.

Evaluation of a rapid immunochromatographic test for the detection of norovirus in stool samples

Worldwide noroviruses are an important cause of gastroenteritis and are major agents of both sporadic as well as epidemic infection. Because of the rapid transmission of the virus, early detection is essential. Until recently, the available test methods for the detection in stool were enzyme immunoassays and real-time reverse transcription polymerase chain reaction (RT-PCR), both of which take several hours to perform. We evaluated the rapid immunochromatographic test RIDA(R)QUICK Norovirus for the detection of norovirus in the stool of patients with acute gastroenteritis. This test is easy to perform and read and only takes 20 min. The sensitivity and specificity compared to RT-PCR results and the positive and negative predictive values were 57.1%, 99.1%, 93.3% and 91.2%, respectively. The rapid test is useful for quick screening, but a negative result should be followed up by RT-PCR.

Frequency of norovirus in stool samples from hospitalized children due to acute gastroenteritis in Anatolia, Turkey, 2006–2007

Noroviruses are among the most common causes of sporadic enteritis in childhood. In this pilot study, the frequency of norovirus infection in children in mid-western Turkey was investigated from November 2006 to June 2007. Noroviruses were detected in 17% of samples (15/88) by a combination of 2 different RT-PCR assays, both targeting an overlapping region of the RNA-dependent RNA polymerase gene. By sequence analysis, most strains were characterized as GIIb/Hilversum. One strain was characterized as GII.4/2006a, a variant that appeared worldwide in 2006, while another strain was characterized as a rare genotype, GII.6. This study demonstrates the importance of norovirus in paediatric diarrhoea and suggests the heterogeneity of circulating strains in Turkey.

Detection and quantification of human and bovine noroviruses by a TaqMan RT-PCR assay with a control for inhibition

Noroviruses are single-stranded RNA viruses belonging to the family Caliciviridae. They are a major cause of epidemic and sporadic gastroenteritis in humans and calves. Reverse transcription-polymerase chain reaction (RT-PCR) has become the "gold standard" for detection of noroviruses in faecal and environmental samples. However, false negative results due to co-concentration of RT-PCR inhibitors are a continuous concern. A TaqMan real-time RT-PCR assay making use of a foreign internal RNA control and a RNA standard was developed. Very interestingly, this method is capable of detecting human noroviruses belonging to genogroups I and II, and bovine noroviruses belonging to genogroup III. Inhibitors were removed efficiently by 1/10 dilution of the sample or addition of bovine serum albumin to the RT-PCR mix. This assay was validated with human and bovine stool samples previously tested for norovirus by conventional RT-PCR. The ability to detect norovirus in stool samples that were negative by conventional RT-PCR assay demonstrate the higher sensitivity of the TaqMan assay compared to the conventional RT-PCR assay. This real-time RT-PCR assay allows the detection of both human and bovine noroviruses, avoids false negative results and is able to quantify the level of norovirus contamination.

Evaluation of immunochromatography and commercial enzyme-linked immunosorbent assay for rapid detection of norovirus antigen in stool samples

The efficiency of immunochromatography and commercial enzyme-linked immunosorbent assay (ELISA) kit (Denka Seiken Co. Ltd., Tokyo, Japan) were evaluated for rapid detection of norovirus (NoV) from stool specimens. A total of 503 stool specimens collected from infants and young children who suffered from acute gastroenteritis were tested for NoV by the NoV-immunochromatography kit, Denka ELISA kit, and by a monoplex RT-PCR method. The NoV-immunochromatography revealed 78.9% sensitivity, 96.4% specificity, and 92.4% efficiency with the monoplex RT-PCR method. The Denka ELISA kit had a sensitivity of 90.4%, specificity of 96.4%, and an efficiency level of 95%. The findings indicate that the newly developed NoV-immunochromatography kit provides the specificity equal to that of the Denka ELISA kit, even through the sensitivity of detection was lower. However, the advantage of the NoV-immunochromatography kit is less time consuming and simpler. The data show that both the Denka ELISA and the NoV-immunochromatography kits may be used as an alternative method for screening of NoV in stool samples.