Epidemiology Of Noroviruses Research Articles

Norovirus in Latin America: Systematic Review and Meta-analysis.

Noroviruses are increasingly recognized as a major cause of sporadic and epidemic acute gastroenteritis (AGE). Although there have been multiple studies published on norovirus epidemiology in Latin America, no comprehensive assessment of the role of norovirus has been conducted in the region. We aim to estimate the role of norovirus in the Latin American region through a systematic review and meta-analysis of the existing literature. We carried out a literature search in MEDLINE, SciELO and LILACS. We included papers that provided information on the prevalence or incidence of norovirus (including seroprevalence studies and outbreaks), with a recruitment and/or follow-up period of at least 12 months and where the diagnosis of norovirus was confirmed by reverse transcription polymerase chain reaction. The data were pooled for meta-analysis to estimate the prevalence of norovirus AGE and norovirus asymptomatic infection with 95% confidence intervals (CIs). Thirty-eight studies were included in the review. Overall, the prevalence of norovirus among AGE cases was 15% (95% CI: 13-18). By location, it was 15% in the community (95% CI: 11%-21%), 14% in outpatient settings (95% CI: 10%-19%) and 16% in hospital locations (95% CI: 12%-21%). The prevalence of norovirus among asymptomatic subjects was 8% (95% CI: 4-13). Norovirus GII.4 strains were associated with 37%-100% of norovirus AGE cases, but only 7% of norovirus asymptomatic detections. Noroviruses are associated with almost 1 out of every 6 hospitalizations because of acute diarrhea in children younger than 5 years of age in Latin America.

THE BURDEN AND FUTURE SCOPE FOR IMPORTANT VIRAL ENTERIC PATHOGENS IN AFRICA

BackgroundThe burden of viral enteric infections in Africa is enormous, although poorly described. Some, such as rotavirus, are well recognized, whereas others including norovirus or enteric adenovirus (EAd), show high...

Norovirus and Sapovirus Epidemiology and Strain Characteristics among Navajo and Apache Infants.

Norovirus and sapovirus are important causes of acute gastroenteritis (AGE) among American Indian infants. We investigated the prevalence and molecular epidemiology of norovirus and sapovirus in American Indian infants who have historically experienced a high burden of AGE compared to other US populations. Stool samples were collected from 241 children with AGE (cases) and from 343 infants without AGE (controls) ≤9 months of age from 2002–2004. Cases experienced forceful vomiting and/or 3 or more watery or looser-than-normal stools in 24 hours. Stools were tested by real-time RT-PCR for norovirus GI, GII and GIV and sapovirus GI, GII, GIV and GV. Positive samples were genotyped after sequencing conventional RT-PCR products. Norovirus was identified in 76 (31.5%) of the cases and 70 (20.4%) of the controls (p<0.001). GII.3 and GII.4 Farmington Hills were the most frequently identified genotypes in 14.5% and 30.3% of cases and 17.1% and 27.1% of controls, respectively. Sapovirus GI and GII genotypes were identified in 8 (3.3%) of cases and 8 (2.3%) of controls and a single GIV virus was detected in a control. The same norovirus and sapovirus genotypes were circulating in the general U.S. population in the same time period. The high detection rate of norovirus in healthy controls suggests significant asymptomatic transmission in young infants in these communities.

Molecular epidemiology of noroviruses detected in Vietnamese children with acute gastroenteritis from 2012 to 2015

Noroviruses, an important cause of diarrhoea in humans, are genetically diverse. The recent norovirus seasons recorded the emergence of new recombinants of the capsid and polymerase genotypes, with a global dominance of GII.Pe_GII.4 Sydney 2012 and GII.P17_GII.17 in Asian countries. However, the number of papers reporting the distribution of both polymerase and capsid genotypes circulating among children is scarce, with none from Vietnam. This study described both the polymerase and capsid genotypes of noroviruses circulating in Vietnamese children using stool specimens obtained under the World Health Organization rotavirus surveillance programme from 2012 to 2015. Of 350 specimens tested, noroviruses were detected in 90 (28 %) of 319 inpatient specimens and in 9 (29 %) of 31 outpatient specimens. The polymerase and capsid genotype combinations of GII.Pe_GII.4 Sydney 2012 and GII.P21_GII.3 were co-dominant (51 and 24 %, respectively), both of which were recombinants, contributing to a high proportion (87 %) of recombinants among circulating noroviruses. GII.4 variants evolved in the same fashion in Vietnam as in other countries, with amino acid substitutions in the putative variant-specific epitopes of the protruding domain. Unlike neighbouring countries where the predominance of GII.P17_GII.17 was reported, only one GII.P17_GII.17 strain was detected from an outpatient in 2015 in Vietnam. In conclusion, a substantial burden due to norovirus gastroenteritis hospitalizations among Vietnamese children was associated with circulating co-dominant GII.Pe_GII.4 Sydney 2012 and GII.P21_GII.3 strains. Continued surveillance is necessary to monitor infection caused by GII.4 variants and that of GII.P17_GII.17 noroviruses in paediatric patients in Vietnam.

Molecular epidemiology of norovirus in asymptomatic food handlers in Busan, Korea, and emergence of genotype GII.17.

The molecular epidemiology of norovirus infections was studied in food handlers without any symptoms from January to December 2015 in Busan city, Korea. A total of 2,174 fecal specimens from asymptomatic food handlers were analyzed, and 2.3% (49/2,174) were norovirus-positive. Fourteen of 335 samples (4.2%) were positive in January; fifteen of 299 samples (5.0%) in February, and seven of 189 samples (3.7%) in December. However, norovirus was rarely detected in other months. From sequencing analysis, 11 genotypes (five GI and six GII genotypes) were detected. Among the 42 capid gene sequences identified, 14 were from the GI genogroup, while 28 were from the GII genogroup. The most commonly detected genotype was GII.17, comprising 15 (35.7%) of positive samples. From January 2012 to December 2015, 5,138 samples were collected from gastroenteritis patients and outbreaks in Busan. The most detected genotype in 2012, 2013, and 2014 was GII.4 (121, 24, and 12 cases, respectively), but in 2015, GII.17 (25 cases) was the most common. The GII.4 genotype was the major cause of acute gastroenteritis from 2012 to 2014, but the GII.17 genotype became the most prevalent cause in 2015. Continued epidemiological surveillance of GII.17 is needed, together with assessment of the risk of norovirus infection.

Molecular epidemiology of GI and GII noroviruses in sewage: 1-year surveillance in eastern China.

To determine the concentration and molecular epidemiology of GI and GII noroviruses in sewage in China. Twenty-three raw sewage samples were collected in the cities of Jinan and Linyi, eastern China in 2014. GI and GII noroviruses were positive in all samples after TaqMan-based quantitative PCR. The mean concentrations of GI and GII noroviruses were 4·52×10(4) and 7·88×10(4) genome copies per litre respectively. After reverse transcription-PCR, cloning and sequencing, 16 genotypes were identified. GI.6 (69·6%), GI.2 (65·2%), GII.13 (65·2%), GII.6 (60·9%) and GII.17 (60·9%) were the most common GI and GII genotypes. A recombination event was observed in two GI.6 sequences. GII.4 sequences belonged to Sydney 2012 and Den Haag 2006b variant. Interestingly, the novel GII.17 Kawasaki308 variant was detected. These results reveal that multiple norovirus genotypes cocirculated in the local population. The risk of acute gastroenteritis outbreak is high in the two cities due to the detection of GII.17 Kawasaki308 variant and the high concentration of norovirus in raw sewage. This study demonstrates sewage surveillance can be a useful approach to monitor norovirus circulating in the population.

Norovirus molecular detection in Uruguayan sewage samples reveals a high genetic diversity and GII.4 variant replacement along time.

To determine the prevalence and molecular epidemiology of norovirus (NoV) genogroup I (GI) and GII in Uruguay. One hundred and sixteen sewage samples were collected in six cities (Bella Unión, Salto, Paysandú, Fray Bentos, Melo and Treinta y Tres) from March 2011 to April 2013, viruses were concentrated by ultracentrifugation and NoV studies were performed by semi-nested RT-PCR (partial capsid region). NoV were detected in samples from all the cities and detected in 72% (84/116) of the samples with nine of them belonging to GI, 48 to GII and 27 to both genogroups. Remarkably, a high genetic diversity was identified: GII.2 (n = 13), GII.4 (n = 13), GI.1 (n = 5), GI.4 (n = 5), GI.8 (n = 4), GII.13 (n = 4), GII.1 (n = 3), GII.6 (n = 3), GI.3 (n = 1), GI.5 (n = 1), GI.6 (n = 1), GII.3 (n = 1), GII.17 (n = 1). Interestingly, a complete replacement of GII.4 New Orleans 2009 by GII.4 Sydney 2012 variants during 2012 was evidenced. This study reveals a high circulation of different NoV GI and GII genotypes in sewage evidencing a replacement of GII.4 variants. This approach can be used as an indicator of the presence of a new GII.4 variant which can originate an increase in acute gastroenteritis outbreaks worldwide.

Norovirus diarrhea in Bangladesh, 2010-2014: prevalence, clinical features, and genotypes.

Norovirus infections in diarrhea patients attending an urban and a rural hospital in Bangladesh were investigated. A total of 953 fecal specimens from both children and adults collected during 2010-2014 were tested for the presence of norovirus using real time PCR. One fourth (25%) of the specimens were positive for norovirus RNA which was identified both in children and adults. Norovirus was associated with short duration of diarrhea, high abdominal pain, and more moderate to severe dehydration when compared with rotavirus infections. Norovirus GII (69%) was the most prevalent genogroup followed by GI (18%), mixed GI/GII/GIV (11%), and GIV (2%). Among GII genogroup, GII.4 (42%) was the most prevalent genotype followed by GII.3 (21%), GII.6 (7%), GII.7 (6%), and GII.21 (6%). GII.4 and GII.3 strains were frequently identified (82% and 75%, respectively) in children <2 years of age and less commonly (16% and 15%) in adults more than 18 years of age. The present study reinforces the importance of norovirus-associated hospitalizations both in children and adults. The dynamic molecular epidemiology of norovirus requires routine strain surveillance to identify changes in prevailing strains. J. Med. Virol. 88:1742-1750, 2016. © 2016 Wiley Periodicals, Inc.

Norovirus Infection and Acquired Immunity in 8 Countries: Results From the MAL-ED Study.

Norovirus is an important cause of childhood diarrhea. We present data from a longitudinal, multicountry study describing norovirus epidemiology during the first 2 years of life. A birth cohort of 1457 children across 8 countries contributed 7077 diarrheal stools for norovirus testing. A subset of 199 children contributed additional asymptomatic samples (2307) and diarrheal stools (770), which were used to derive incidence rates and evaluate evidence for acquired immunity. Across sites, 89% of children experienced at least 1 norovirus infection before 24 months, and 22.7% of all diarrheal stools were norovirus positive. Severity of norovirus-positive diarrhea was comparable to other enteropathogens, with the exception of rotavirus. Incidence of genogroup II (GII) infection was higher than genogroup I and peaked at 6-11 months across sites. Undernutrition was a risk factor for symptomatic norovirus infection, with an increase in 1 standard deviation of length-for-age z score associated with a 17% reduction (odds ratio, 0.83 [95% confidence interval, .72-.97]; P = .011) in the odds of experiencing diarrhea when norovirus was present, after accounting for genogroup, rotavirus vaccine, and age. Evidence of acquired immunity was observed among GII infections only: Children with prior GII infection were found to have a 27% reduction in the hazard of subsequent infection (hazard ratio, 0.727; P = .010). The high prevalence of norovirus across 8 sites in highly variable epidemiologic settings and demonstration of protective immunity for GII infections provide support for investment in vaccine development.

Norovirus as the cause of medically attended gastroenteritis: a hospital-based experience.

Gastroenteritis remains an important cause of morbidity and mortality worldwide. With the introduction of vaccines against rotavirus, interest has shifted to understanding the epidemiology of norovirus (NoV). While the importance of NoV in gastroenteritis outbreaks is well established, its role in sporadic gastroenteritis is less known. To better define the role of NoV as a cause of sporadic gastroenteritis we investigated its prevalence in the patients seen in our paediatric hospital with special emphasis on its seasonal and age distribution. Over a 12-month period discarded stool specimens submitted to our paediatric hospital for testing of an infectious aetiology were retrieved and additionally tested for NoV by real-time reverse transcriptase-polymerase chain reaction; demographical and clinical information were also obtained. Overall, NoV was the single most commonly identified pathogen and found in 68/892 (7·6%) total specimens or 68/258 (26%) of pathogen-positive specimens. The highest rates of NoV were detected in children aged 6 months to 4 years (50/332, 15·1%) and presenting between October and January (46/314, 14·7%). NoV has become the main cause of gastroenteritis in our paediatric population.

Molecular epidemiology of noroviruses associated with sporadic gastroenteritis in Guangzhou, China, 2013-2015.

Norovirus diarrhea is a great threat to public health worldwide. To characterize the prevalence of circulating noroviruses associated with sporadic gastroenteritis cases in Guangzhou, 215 stool specimens were collected during two consecutive cold seasons in 2013-2015. Noroviruses were detected in 25 (11.63 %) samples, and GII.4 (6/9) and GII.17 (10/16) were identified as the most predominant variants of each of those seasons. The remaining strains belonged to the genotypes GII.P12/GII.3, GII.2, and GI.Pb/GI.6. The phylogenetic relationships of the GII.17 strains were analyzed based on their capsid protein sequences. This study suggests a significant shift of predominant variants associated with sporadic gastroenteritis in Guangzhou.

Norovirus Surveillance: An Epidemiological Perspective.

Surveillance for norovirus is challenging because the nature of illness due to norovirus is such that the majority of people who are infected will not have any contact with medical services and are highly unlikely to have a sample collected for diagnosis. Public health advice urges people to not visit hospitals or their family physicians, to prevent the risk further spread. The recognition of the importance of this pathogen was quickly established following the introduction of surveillance of outbreaks of gastrointestinal infection in England and Wales in 1992. This period saw >1800 outbreaks of norovirus infection reported in hospitals in England, affecting >45 000 patients and staff. A new system for reporting outbreaks of norovirus infection in hospitals, the Hospital Norovirus outbreak Reporting Scheme (HNORS), began in January 2009. Summary information on outbreaks is provided by infection control staff at hospitals and includes questions on the date the first and last person in the outbreak became symptomatic and whether closure of a bay or ward was needed. In the first 3 years (2009-2011) of the HNORS surveillance scheme, 4000 outbreaks were reported, affecting 40 000 patients and 10 000 staff. Over the last 3 years, these outbreaks have been associated with an average of 13 000 patients and 3400 staff becoming ill, with 15 000 lost bed-days annually. With the possible introduction of a vaccine on the horizon, targeted research with a more integrated approach to laboratory testing and outbreak reporting is essential to a greater understanding of the epidemiology of norovirus.

Molecular Epidemiology and Genetic Diversity of Norovirus in Young Children in Phnom Penh, Cambodia.

This study investigated the genetic diversity of noroviruses identified from a previous surveillance study conducted at the National Pediatric Hospital in Phnom Penh, Cambodia, from 2004 to 2006. In the previous study, 926 stool samples were collected from children aged 3–60 months with acute diarrhea (cases) and without diarrhea (controls) with reported 6.7% of cases and 3.2% of controls being positive for norovirus. The initial norovirus diagnostic assay was performed with real-time reverse transcription-polymerase chain reaction (real-time RT PCR) which also distinguished between genogroups I and II (GI and GII). Norovirus infection was most commonly detected in children aged 12–23 months in both cases and controls. Norovirus Genotyping Tool and phylogenetic analysis of partial sequences of the 3′ end of the RNA-dependent RNA Polymerase (RdRp) and the capsid domain region were employed to assign genotypes of the norovirus strains. GII.4 was the most predominant capsid genotype detected at 39.5% followed by GII.6 at 14.9%. The GII.4 Hunter 2004 variant was the predominant strain detected. Six RdRP/capsid recombinants including GII.P7/GII.6, GII.P7/GII.14, GII.P7/GII.20, GII.P12/GII.13, GII.P17/GII.16, and GII.P21/GII.3 were also identified. This study of norovirus infection in young children in Cambodia suggests genetic diversity of norovirus as reported worldwide.

Outbreak of Norovirus GII.P17-GII.17 in the Canadian Province of Nova Scotia.

Background. Norovirus is the leading cause of viral gastroenteritis, with GII.4 being the most common circulating genotype. Recently, outbreaks in China revealed that norovirus GII.17 GII.P17 had become predominant. Objective. This study aimed to characterize the distribution of norovirus genotypes circulating in Nova Scotia. Methods. Stool specimens were collected from gastrointestinal outbreaks in Nova Scotia between Jan 2014 and June 2015 and subjected to real-time RT-PCR. Norovirus-positive specimens were referred to the National Microbiology Laboratory for sequence-based genotyping. Results. The first norovirus GII.P17-GII.17 outbreak in Canada was identified, but no widespread activity was observed in Nova Scotia. Discussion. It is unknown whether GII.P17-GII.17 is more widespread in Canada since contributions to Canadian surveillance are too sparse to effectively monitor the epidemiology of emerging norovirus genotypes. Conclusions. Presence of norovirus GII.17:P17 in Canada highlights the need for more systematic surveillance to ensure that molecular targets used for laboratory detection are effective and help understand norovirus evolution, epidemiology, and pathogenesis.

Molecular epidemiology of norovirus in children and the elderly in Atlanta, Georgia, United States.

Noroviruses are an important cause of gastroenteritis, which can be severe at the extremes of ages. Data documenting the endemic burden of norovirus among children and elderly adults are lacking. Stool specimens submitted for clinical testing were collected from elderly (≥ 65 years) adults and children (<18 years) with acute vomiting and/or diarrhea seeking care at several metropolitan Atlanta adult and pediatric hospitals from January 2013-June 2013. Specimens were tested for norovirus with real-time RT-PCR and sequenced if norovirus was detected. Corresponding clinical and demographic data were abstracted from retrospective chart review. Norovirus was detected in 11% (11/104) of elderly specimens and 11% (67/628) of pediatric, with GII.4 Sydney_2012 detected in 64% (7/11) of elderly norovirus-positive and 11% (8/67) of pediatric specimens, P < 0.001. In comparison to hospitalized children, hospitalized elderly with norovirus were more commonly admitted to the intensive care unit (ICU) (36% vs. 7%, P = 0.02). Norovirus in the elderly can be associated with severe illness requiring ICU admissions. The pediatric group demonstrated greater variability in genotype distribution. Ongoing surveillance of norovirus genotypes is crucial for norovirus vaccine development in understanding circulating and emerging genotypes.

Whole genome sequencing of fecal samples as a tool for the diagnosis and genetic characterization of norovirus

BackgroundNorovirus is a major cause of gastroenteritis, causing yearly epidemics and hospital outbreaks resulting in a high burden on health care. Detection and characterization of norovirus directly from clinical samples could provide a powerful tool in infection control and norovirus epidemiology. ObjectivesTo determine whether next-generation sequencing directly on fecal samples can accurately detect and characterize norovirus. Study designWhole genome sequencing was performed on fecal samples from 10 patients with gastro-enteritis. Norovirus infection had previously been confirmed by RT-PCR. Genotyping was performed using phylogenetic analysis. ResultsFrom all clinical samples sufficient amounts of RNA were retrieved to perform whole-transcriptome sequencing for the detection of RNA-viruses. Complete genomic norovirus sequences were obtained from all clinical samples, permitting accurate genotyping by phylogenetic analysis. In addition, a complete coxsackie B1 virus genome was isolated. ConclusionDetailed information on viral content can be obtained from fecal samples in a single-step approach, supporting clinical and epidemiological purposes. Next-generation sequencing performed directly on clinical samples can become a powerful tool in patient care and infection control.

Genotype distribution of norovirus around the emergence of Sydney_2012 and the antigenic drift of contemporary GII.4 epidemic strains

BackgroundThe pattern of epochal evolution of NoV is ongoing, while novel GII.4 variants emerge and cause new pandemics. Since, the emergence in March 2012, Sydney_2012 had replaced GII.4-2009 as the primary NoV strain in most countries in the northern hemisphere by November 2012. ObjectivesTo determine the genotype distribution around the emergence of Sydney_2012 and to investigate the underlying evolution mechanisms of the contemporary GII.4 strains. Study designFrom January 2012 to December 2013, molecular epidemiology of norovirus in 846 adults (≥16 years) in Shanghai were conducted. The VP1 proteins of the contemporary GII.4 strains (Den_Haag_2006b, New_Orleans_2009 and Sydney_2012) were expressed in vitro and purified. Receptor binding patterns of these three epidemic strains were determined through histo-blood group antigen (HBGA) binding assays. Convalescent serum from patients infected with GII.4 epidemic strains were employed to investigate the role of antigenic drift in the persistence of GII.4 epidemic strains through receptor-binding blockade assays. ResultsEpidemiological studies revealed that Sydeny_2012 has completely replaced Den_Haag_2006b and New_Orleans_2009 and has been the dominant circulating strain in Shanghai since its emergence in October 2012. Interestingly, Den_Haag_2006b and New_Orleans_2009 have been co-circulating in Shanghai before the emergence of Sydeny_2012. The contemporary GII.4 epidemic norovirus strains displayed commonly high tropism to the histo-blood group antigen receptors, whereas Sydeny_2012 was antigenically different from Den_Haag_2006b and New_Orleans_2009. ConclusionsAntigenic drift, rather than receptor switch, played a key role in the emergence and spreading of Sydney_2012. The contemporary GII.4 strains were evolving via epochal evolution without altered ligand binding profiles.

GII.4 Sydney_2012 norovirus infection in immunocompromised patients in Beijing and its rapid evolution in vivo.

To study the epidemiology and evolution of norovirus (NoV) in immunocompromised patients in a tertiary hospital in China. Stool specimens were collected from 131 hospitalized patients presenting with diarrhea from July 1, 2012, to June 30, 2013, and were tested for NoV using RT-PCR. RT-PCR was performed to amplify the complete capsid genome for a series of samples from chronic diarrhea patients, and nucleotide and amino acid changes were analyzed. There were nine NoV-positive patients among 124 immunocompromised patients (7.3%); all nine were infected with GII.4 Sydney_2012 strain. In three chronic diarrhea patients, the GII.4 Sydney_2012 strains accumulated 19, 18, and eight nucleotide mutations within 110, 113, and 22 days, respectively, most were non-synonymous. The greatest number of stable amino acid mutations was 10 in patient 2; eight stable mutations (including three in antigenic sites) occurred while the patient was asymptomatic and shedding the virus. GII.4 Sydney_2012 strain tends to undergo stable mutations during the asymptomatic shedding phase and may generate new variants in chronic diarrhea patients.

Multiplex real-time RT-PCR for the simultaneous detection and quantification of GI, GII and GIV noroviruses

Noroviruses are important causes of acute gastroenteritis and are classified into six genogroups with GI, GII and GIV containing human pathogens. This high genetic diversity represents a significant challenge for diagnostic assay development. Genogroup specific monoplex and multiplex real time RT-PCR assays are widely used for the detection of GI and GII noroviruses. On the other hand, GIV norovirus detection is not part of routine laboratory diagnosis. This study describes the development and evaluation of a one tube, real time RT-PCR assay for the simultaneous detection and quantification of GI, GII and GIV noroviruses, including both GIV.1 (human) and GIV.2 (animal) strains. Assay performance was evaluated on a panel of norovirus positive clinical samples by comparison of monoplex and multiplex standard curves and Ct values. The multiplex assay demonstrated equal sensitivity and specificity to the monoplex assays and was able to detect all GI, GII and GIV noroviruses with Ct values equal to that of the monoplex assays. The multiplex assay described in this study will be instrumental for the better understanding of GIV norovirus epidemiology, including their possible zoonotic nature.

Epidemiology and Genetic Characterization of Noroviruses among Adults in an Endemic Setting, Peruvian Amazon Basin, 2004-2011.

BackgroundSuccessful vaccination strategies against norovirus will require understanding the burden of disease and relevant genotypes in populations. However, few data are available from cohort studies of adults living in low- and middle-income countries (LMIC).Materials and MethodsWe conducted a nested case-control study within a Peruvian military cohort to characterize the burden of norovirus infection, predominant genotypes, and associated symptoms from 2004 through 2011. Randomly selected case and control stools were tested for norovirus, bacteria, and parasites. The odds ratio of the association between norovirus infection and diarrhea was estimated using multiple logistic regression and co-infection adjusted attributable fractions were calculated.ResultsOf the 3,818 cohort study participants, 624 developed diarrhea. Overall and norovirus-associated diarrhea incidence rates were 42.3 and 6.0 per 100 person-years, respectively. The most prevalent norovirus genogroup was GII (72.5%, 29/40), which was associated with diarrhea (AOR 3.4, 95% CI: 1.3–8.7, P = 0.012). The co-infection adjusted GII attributable fraction was 6.4%.DiscussionNorovirus was a frequent cause of diarrhea in an adult population followed longitudinally in an LMIC setting. Vaccine strategies should consider targeting adults in endemic settings and special populations that could serve as community transmission sources.