Academic literature on the topic 'Caliciviridae Infections'
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Journal articles on the topic "Caliciviridae Infections"
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Desselberger, Ulrich. "Caliciviridae Other Than Noroviruses." Viruses 11, no. 3 (March 21, 2019): 286. http://dx.doi.org/10.3390/v11030286.
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Besides noroviruses, the Caliciviridae family comprises four other accepted genera: Sapovirus, Lagovirus, Vesivirus, and Nebovirus. There are six new genera proposed: Recovirus, Valovirus, Bavovirus, Nacovirus, Minovirus, and Salovirus. All Caliciviridae have closely related genome structures, but are genetically and antigenically highly diverse and infect a wide range of mammalian host species including humans. Recombination in nature is not infrequent for most of the Caliciviridae, contributing to their diversity. Sapovirus infections cause diarrhoea in pigs, humans and other mammalian hosts. Lagovirus infections cause systemic haemorrhagic disease in rabbits and hares, and vesivirus infections lead to lung disease in cats, vesicular disease in swine, and exanthema and diseases of the reproductive system in large sea mammals. Neboviruses are an enteric pathogen of cattle, differing from bovine norovirus. At present, only a few selected caliciviruses can be propagated in cell culture (permanent cell lines or enteroids), and for most of the cultivatable caliciviruses helper virus-free, plasmid only-based reverse genetics systems have been established. The replication cycles of the caliciviruses are similar as far as they have been explored: viruses interact with a multitude of cell surface attachment factors (glycans) and co-receptors (proteins) for adsorption and penetration, use cellular membranes for the formation of replication complexes and have developed mechanisms to circumvent innate immune responses. Vaccines have been developed against lagoviruses and vesiviruses, and are under development against human noroviruses.
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Delwart, Eric, Michael J. Tisza, Eda Altan, Yanpeng Li, Xutao Deng, Dennis J. Hartigan-O’Connor, and Amir Ardeshir. "Idiopathic Chronic Diarrhea in Rhesus Macaques Is Not Associated with Enteric Viral Infections." Viruses 13, no. 12 (December 14, 2021): 2503. http://dx.doi.org/10.3390/v13122503.
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While recent changes in treatment have reduced the lethality of idiopathic chronic diarrhea (ICD), this condition remains one of the most common causes of rhesus macaque deaths in non-human primate research centers. We compared the viromes in fecal swabs from 52 animals with late stage ICD and 41 healthy animals. Viral metagenomics targeting virus-like particles was used to identify viruses fecally shed by each animal. Five viruses belonging to the Picornaviridae, one to the Caliciviridae, one to the Parvoviridae, and one to the Adenoviridae families were identified. The fraction of reads matching each viral species was then used to estimate and compare viral loads in ICD cases versus healthy controls. None of the viruses detected in fecal swabs were strongly associated with ICD.
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Fernandez-Cassi, Xavier, Sandra Martínez-Puchol, Marcelle Silva-Sales, Thais Cornejo, Rosa Bartolome, Silvia Bofill-Mas, and Rosina Girones. "Unveiling Viruses Associated with Gastroenteritis Using a Metagenomics Approach." Viruses 12, no. 12 (December 13, 2020): 1432. http://dx.doi.org/10.3390/v12121432.
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Acute infectious gastroenteritis is an important illness worldwide, especially on children, with viruses accounting for approximately 70% of the acute cases. A high number of these cases have an unknown etiological agent and the rise of next generation sequencing technologies has opened new opportunities for viral pathogen detection and discovery. Viral metagenomics in routine clinical settings has the potential to identify unexpected or novel variants of viral pathogens that cause gastroenteritis. In this study, 124 samples from acute gastroenteritis patients from 2012–2014 previously tested negative for common gastroenteritis pathogens were pooled by age and analyzed by next generation sequencing (NGS) to elucidate unidentified viral infections. The most abundant sequences detected potentially associated to acute gastroenteritis were from Astroviridae and Caliciviridae families, with the detection of norovirus GIV and sapoviruses. Lower number of contigs associated to rotaviruses were detected. As expected, other viruses that may be associated to gastroenteritis but also produce persistent infections in the gut were identified including several Picornaviridae members (EV, parechoviruses, cardioviruses) and adenoviruses. According to the sequencing data, astroviruses, sapoviruses and NoV GIV should be added to the list of viral pathogens screened in routine clinical analysis.
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Barry, Aline F., Alice F. Alfieri, and Amauri A. Alfieri. "Detection and phylogenetic analysis of porcine enteric calicivirus, genetically related to the Cowden strain of sapovirus genogroup III, in Brazilian swine herds." Pesquisa Veterinária Brasileira 28, no. 1 (January 2008): 82–86. http://dx.doi.org/10.1590/s0100-736x2008000100013.
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Sapovirus of the Caliciviridae family is an important agent of acute gastroenteritis in children and piglets. The Sapovirus genus is divided into seven genogroups (G), and strains from the GIII, GVI and GVII are associated with infections in swine. Despite the high prevalence in some countries, there are no studies related to the presence of porcine enteric sapovirus infections in piglets in Brazil. In the present study, 18 fecal specimens from piglets up to 28 days were examined to determine the presence of sapovirus genome by RT-PCR assay, using primers designed to amplify a 331 bp segment of the RNA polymerase gene. In 44.4% (8/18) of fecal samples, an amplified DNA fragment was obtained. One of these fragments was sequenced and submitted to molecular and phylogenetic analysis. This analysis revealed high similarity, with nucleotides (87%) and amino acids (97.8%), to the Cowden strain, the GIII prototype of porcine enteric calicivirus. This is the first description of sapovirus in Brazilian swine herds.
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SIOCHU (Α. ΣΙΩΧΟΥ), A. "Hepatitis E." Journal of the Hellenic Veterinary Medical Society 54, no. 3 (December 19, 2017): 236. http://dx.doi.org/10.12681/jhvms.15264.
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HEV is responsible for large epidemics of acute hepatitis and sporadic cases in southeast and central Asia, the Middle East, parts of Africa and Mexico. Few HEV infections have been reported in non-travelers in industrialized countries, including the Netherlands. HEV infection spreads by the fecal-oral route, usually through contaminated water. The clinical illness resembles other forms of acute viral hepatitis, with onset after an incubation period of one to eight weeks. Clinical attack rates are the highest among young adults. In younger age groups, infections are more often anicteric and asymptomatic. Chronic HEV infection has not been observed. Although the death rate is usually low (0.07% to 0.6%), the illness may be particularly severe among pregnant women, with death rates as high as 25%. To date, no specific treatment is available for HEV infection. Ensuring a clean drinking water supply remains the best preventive strategy. HEV is a small, non-enveloped virus that has apositive-sense, single-stranded RNA genome of approximately 7.2 Kb. The genome contains three open reading frames (ORFs). In general, different genotypes circulate within different geographical areas, (genotype 1: Southeast and Central Asia, genotype 2: Mexico, genotype 3: USA-US1,US2 , SwUS and genotype 4: China). HEV was initially considered to be a member of the family Caliciviridae. However, on the basis of comparative phylogenetic analysis, it was recendy removed from the Caliciviridae family. In Western Europe and the United States, clinical cases of hepatitis caused by HEV are rare and most often they have been associated with travel to areas, where HEV is endemic. However, novel strains of HEV have been isolated in the US and in Europe from patients without a history of travel to regions endemic for HEV. Serological studies in industrialized countries have shown that the prevalence of anti-HEV antibodies is 1-6% among blood donors and is much higher in some populations. The cause of this relatively high prevalence of anti-HEV in countries, where clinical hepatitis E is rare, is unknown. Balayan et al. first demonstrated that domestic pigs could be experimentally infected with a human HEV isolate. Clayson et al. subsequently detected RNA and antibodies of HEV in pigs in Nepal, but the virus was not characterized. A unique swine HEV was first isolated in 1997. Later studies revealed that swine from other countries, such as Australia, Vietnam, Taiwan, Canada, Spain and Greece, were also infected with HEV. The swine HEV strain isolated from a pig in Illinois is genetically very closely related to two U.S. strains of human HEV. Similarly, the swine HEV strains isolated from pigs in Taiwan are closely related to Taiwanese strains of human HEV. Interspecies transmission of HEV has been experimentally demonstrated: swine HEV infected non-human primates and a strain of human HEV infected pigs. Also, HEV from swine might sometimes be transmitted to humans through environmental contact. These findings implicate a possible transmission of the virus from pigs to humans. These data suggested that HEV infection of humans through contact with pigs may be possible and that swine veterinarians and other pig handlers may be at risk of zoonotic infection.
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Radzіkhovskyі, N., О. Dyshkant, O. Tolokevich, and V. Moshkivsky. "EPIZOOTOLOGICAL FEATURES CORONAVIRUS INFECTION IN CATS." Scientific and Technical Bulletin оf State Scientific Research Control Institute of Veterinary Medical Products and Fodder Additives аnd Institute of Animal Biology 22, no. 2 (October 7, 2021): 317–22. http://dx.doi.org/10.36359/scivp.2021-22-2.37.
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The exact number of cats living on our planet is unknown, but there are reports with reference to studies conducted by French scientists from the University of Lyon (France) in 400 million domestic cats, most of which live in the United States and Brazil (93 and about 100 million. in accordance). However, according to researchers, the first place in the world in terms of the number of cats per capita is Australia (ratio of 9:10), and Ukraine is in the top 10 countries with the largest number of domestic cats.
In the mid-90s of the twentieth century, Ukraine faced a new infectious disease that affects different species of the feline family - infectious feline peritonitis (IPC), the causative agent of which is a virus of the family Coronaviridae. Animal coronaviruses have been a problem for more than 50 years, however, given their variability and large diversity, the study of this group of viruses continues today.
The article presents data on the epizootological features of coronavirus infection in cats for the period 2019 - 2020 in veterinary clinics in Zhytomyr and Kyiv. During a certain period of time, during the experiment, 115 samples were taken for the study, of which 95 animals were detected with the virus of the family Coronaviridae.
The paper highlights the results of the study of age and breed predisposition. It has been found that 2-6 month old kittens are most prone, especially breeds such as British, Persian and Scottish. Indicators of seasonality of manifestation, and also dynamics of morbidity of cats with a coronavirus infection are resulted. In the spring and summer, the peak incidence of the studied disease was noted.
According to the results of the epizootic analysis, a nosological profile of infectious diseases in cats was formed, which is represented by 8 infections, and the most frequently registered diseases are caused by viruses of the families Herpesviridae Caliciviridae and Parvoviridae.
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Levenson, Eric Andrew, Craig Martens, Kishore Kanakabandi, Charles Turner, Stanislav V. Sosnovtsev, Stacey Ricklefs, Stephen Porcella, and Kim Y. Green. "The host response to murine norovirus infection induces significant engagement of IFN and TNF-a immunological programs." Journal of Immunology 198, no. 1_Supplement (May 1, 2017): 158.2. http://dx.doi.org/10.4049/jimmunol.198.supp.158.2.
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Abstract Norovirus, a positive stranded RNA virus in the family Caliciviridae, is a major cause of acute gastroenteritis. Outbreaks occur primarily in locations such as schools, nursing homes, and cruise ships where individuals are in close proximity. An acute norovirus infection can become chronic in immunocompromised individuals, and an effective antiviral drug is needed. The 7.5 kb genome encodes a polyprotein in ORF1 that is co-translationally cleaved by the viral protease into six nonstructural proteins. The two structural proteins, VP1 and VP2, are encoded in ORF2 and ORF3, respectively. The viral proteins mediate replication and packaging of the genome into icosahedral capsids. The host cell provides additional proteins and building blocks for replication, but only a few essential host factors have been elucidated. To gain insight into the host response to norovirus infection, we performed next generation sequencing-based RNA sequencing on murine macrophages infected with murine norovirus. We obtained RNA from a time course of infection at 0, 8, 14, and 20 hours post infection with mock infections at 0 and 20 hours. Analysis of the host transcriptome reveals full activation of cellular immune response pathways, with NF-kβ, STAT1, and STAT3-based signaling evident. In addition, we observed transcriptional evidence of IRF3 activation with a transition to IRF3/IRF7 signaling. TNF-a-based activation is also clear with most downstream effectors up-regulated. These observations correlate well with the known cytokine response from patient serum samples, disease progression, and symptomatology of human norovirus. We are currently applying these findings toward drug discovery efforts.
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Sharif, Muhammad, Yeong-Bin Baek, Thu Ha Nguyen, Mahmoud Soliman, and Kyoung-Oh Cho. "Porcine sapovirus-induced RIPK1-dependent necroptosis is proviral in LLC-PK cells." PLOS ONE 18, no. 2 (February 3, 2023): e0279843. http://dx.doi.org/10.1371/journal.pone.0279843.
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Sapoviruses belonging to the genus Sapovirus within the family Caliciviridae are commonly responsible for severe acute gastroenteritis in both humans and animals. Caliciviruses are known to induce intrinsic apoptosis in vitro and in vivo, however, calicivirus-induced necroptosis remains to be fully elucidated. Here, we demonstrate that infection of porcine kidney LLC-PK cells with porcine sapovirus (PSaV) Cowden strain as a representative of caliciviruses induces receptor-interacting protein kinase 1 (RIPK1)-dependent necroptosis and acts as proviral compared to the antiviral function of PSaV-induced apoptosis. Infection of LLC-PK cells with PSaV Cowden strain showed that the interaction of phosphorylated RIPK1 (pRIPK1) with RIPK3 (pRIPK3), mixed lineage kinase domain-like protein (pMLKL) increased in a time-dependent manner, indicating induction of PSaV-induced RIPK1-dependent necroptosis. Interfering of PSaV-infected cells with each necroptotic molecule (RIPK1, RIPK3, or MLKL) by treatment with each specific chemical inhibitor or knockdown with each specific siRNA significantly reduced replication of PSaV but increased apoptosis and cell viability, implying proviral action of PSaV-induced necroptosis. In contrast, treatment of PSaV-infected cells with pan-caspase inhibitor Z-VAD-FMK increased PSaV replication and necroptosis, indicating an antiviral action of PSaV-induced apoptosis. These results suggest that PSaV-induced RIPK1-dependent necroptosis and apoptosis‒which have proviral and antiviral effects, respectively‒counterbalanced each other in virus-infected cells. Our study contributes to understanding the nature of PSaV-induced necroptosis and apoptosis and will aid in developing efficient and affordable therapies against PSaV and other calicivirus infections.
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Buckow, Roman, Sonja Isbarn, Dietrich Knorr, Volker Heinz, and Anselm Lehmacher. "Predictive Model for Inactivation of Feline Calicivirus, a Norovirus Surrogate, by Heat and High Hydrostatic Pressure." Applied and Environmental Microbiology 74, no. 4 (December 21, 2007): 1030–38. http://dx.doi.org/10.1128/aem.01784-07.
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ABSTRACT Noroviruses, which are members of the Caliciviridae family, represent the leading cause of nonbacterial gastroenteritis in developed countries; such norovirus infections result in high economic costs for health protection. Person-to-person contact, contaminated water, and foods, especially raw shellfish, vegetables, and fruits, can transmit noroviruses. We inactivated feline calicivirus, a surrogate for the nonculturable norovirus, in cell culture medium and mineral water by heat and high hydrostatic pressure. Incubation at ambient pressure and 75°C for 2 min as well as treatment at 450 MPa and 15°C for 1 min inactivated more than 7 log10 PFU of calicivirus per ml in cell culture medium or mineral water. The heat and pressure time-inactivation curves obtained with the calicivirus showed tailing in the logarithmic scale. Modeling by nth-order kinetics of the virus inactivation was successful in predicting the inactivation of the infective virus particles. The developed model enables the prediction of the calicivirus reduction in response to pressures up to 500 MPa, temperatures ranging from 5 to 75°C, and various treatment times. We suggest high pressure for processing of foods to reduce the health threat posed by noroviruses.
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Sawaswong, Vorthon, Elizabeth Fahsbender, Eda Altan, Taratorn Kemthong, Xutao Deng, Suchinda Malaivijitnond, Sunchai Payungporn, and Eric Delwart. "High Diversity and Novel Enteric Viruses in Fecal Viromes of Healthy Wild and Captive Thai Cynomolgus Macaques (Macaca fascicularis)." Viruses 11, no. 10 (October 22, 2019): 971. http://dx.doi.org/10.3390/v11100971.
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Cynomolgus macaques are common across South East Asian countries including Thailand. The National Primate Research Center of Thailand, Chulalongkorn University (NPRCT-CU) captures wild-borne cynomolgus macaque for research use. Limited information is available on the enteric viruses and possible zoonotic infections into or from cynomolgus macaques. We characterized and compare the fecal virome of two populations; healthy wild-originated captive cynomolgus macaques (n = 43) reared in NPRCT-CU and healthy wild cynomolgus macaques (n = 35). Over 90% of recognized viral sequence reads amplified from feces were from bacterial viruses. Viruses from seven families of mammalian viruses were also detected (Parvoviridae, Anelloviridae, Picornaviridae, Adenoviridae, Papillomaviridae, Herpesviridae, and Caliciviridae). The genomes of a member of a new picornavirus genus we named Mafapivirus, a primate chapparvovirus, and a circular Rep-encoding single-strand (CRESS) DNA virus were also characterized. Higher abundance of CRESS DNA viruses of unknown tropism and invertebrate-tropic ambidensovirus were detected in wild versus captive macaques likely reflecting dietary differences. Short term rearing in captivity did not have a pronounced effect on the diversity of mammalian viruses of wild cynomolgus macaques. This study is the first report of the fecal virome of cynomolgus macaques, non-human primates frequently used in biomedical research and vaccination studies.
Dissertations / Theses on the topic "Caliciviridae Infections"
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Laurent, Sylvie. "Étude de la protéine de capside des calicivirus des lagomorphes RHDV (Rabbit Haemorrhagic Disease Virus) et EBHSV (European Brown Hare Syndrome Virus) : antigénicité, vaccination et assemblage." Compiègne, 1997. http://www.theses.fr/1997COMP1029.
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Les virus RHDV (Rabbit Haemorrhagic Disease Virus) et EBHSV (European Brown Hare Syndrome Virus) ont été décrits pour la première fois sur le continent européen au début des années 1980. Ces deux virus, responsables d'hépatites nécrosantes, sont capables de tuer 90% d'une population de lapins ou de lièvres en moins 48h. Ils ont été affiliés récemment à la famille des Caliciviridae. Les calicivirus possèdent un génome à ARN simple brin de polarité positive et sont composés d'une simple capside constituée d'une unique protéine structurale de 60KDa. Les protéines de capside de RHDV et EBHSV ont été exprimées dans le système baculovirus/cellules d'insecte. Les protéines de capside recombinantes produites en quantité massive ont été retrouvées dans le surnageant de culture sous la forme de pseudo-particules, présentant les mêmes caractéristiques morphologiques et antigéniques que les virions infectieux. Les particules recombinantes de RHDV utilisées dans des tests de vaccination ont conféré une protection équivalente à celle démontrée par les vaccins actuellement commercialisés. L'étude de la séroconversion des lapins vaccinés a mis en évidence le rôle clef de la réponse humorale dans la protection contre la maladie. Ces résultats ont conduit à l'élaboration d'un vaccin recombinant actuellement en cours de développement industriel. L'utilisation des particules recombinantes de RHDV et de EBHSV lors d'études comparatives, réalisées à l'aide de plusieurs anticorps monoclonaux anti-RHDV et anti-EBHSV, ont permis de caractériser les réactions antigéniques croisées entre les deux virus. Ces résultats couplés à ceux de tests de protection croisée ont permis de classer ces deux virus dans deux sérotypes du même sérogroupe au sein de la famille des Caliciviridae. Plusieurs données concernant l'assemblage des calicivirus, obtenues par l'analyse des particules recombinantes en conditions non dénaturantes, ainsi que par l'analyse des séquences peptidiques, sont discutées.
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Hellard, Éléonore. "Des concepts et méthodes associés à la co-circulation des virus dans les populations naturelles d’hôtes à la nécessité d’interdisciplinarité : l’exemple du chat et de ses virus." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10049.
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De nombreux parasites circulent dans les populations naturelles. Au sein d’un hôte, souvent pluri-infecté, ils peuvent interagir, augmentant ou réduisant le risque d’infection et les symptômes d’autres pathogènes. L’étude de ces interactions commence seulement dans les populations naturelles. Les enjeux sont cruciaux : détecter les interactions d’intérêt, estimer la probabilité de coinfection, comprendre la cocirculation des parasites. La détection des interactions sur le terrain est compliquée par la nature des données (e.g., présence-absence) et les facteurs confondants créant des associations statistiques (fausses interactions). Ce travail visait à mener une réflexion transversale sur ces interactions et le multiparasitisme, avec des applications à des données sérologiques pour 4 virus félins suivis dans des populations rurales de chats domestiques. De nouvelles méthodes de modélisation dynamique et statistique ont été développées pour prendre en compte les facteurs générant de fausses interactions (effet cumulatif de l’âge, facteurs de risque communs) et évaluer le biais des méthodes classiques. Des synergies entre 3 couples de virus félins ont été révélées. On a aussi identifié des caractéristiques comportementales et physiologiques (modes de vie, niveau de testostérone), qui, en modulant l’exposition et la sensibilité aux pathogènes, génèrent une forte hétérogénéité entre les hôtes. Enfin, une vision intégrative des systèmes hôte-parasites est indispensable pour appréhender la complexité des communautés et évaluer l’impact de la multitude d’hôtes, de parasites et d’interactions sur la coévolution, la conservation des espèces et la gestion des maladies infectieusesNumerous parasites circulate within natural host populations. Within a host, often pluri-infected, parasites can interact, increasing or decreasing the infection risk and/or symptoms’ severity of other pathogens. Studies of such interactions only start in natural populations. Their stakes are high: detecting interactions of interest, estimating coinfection probabilities and understanding the cocirculation of parasites. The detection of interactions in the field is however complicated by the nature of data (often presence-absence) and the existence of confounding factors that can create statistical associations (false interactions). This work aimed at having a cross-cutting reflection on those interactions and on multiparasitism, with applications on a rich dataset of four feline viruses followed in rural populations of domestic cats. New dynamical and statistical modeling methods were developed to take into account factors generating false interactions (cumulative effect of age, shared risk factors) and evaluate the biases of classical methods. Synergies between three pairs of feline viruses were revealed. In addition, we identified behavioral and physiological factors (e.g., way of life, testosterone levels) that, by modulating exposition and/or susceptibility to pathogens, generate strong heterogeneity between hosts. Finally, a more integrative approach to host-parasites systems is proposed. It now appears necessary if one wants to deal with communities’ complexity and further evaluate the impact of multiple hosts, multiple parasites and their interactions on their coevolution, species conservation and infectious diseases management
Books on the topic "Caliciviridae Infections"
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U, Desselberger, and Gray J, eds. Viral gastroenteritis. Amsterdam: Elsevier, 2003.
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Hall, Aron J. Updated norovirus outbreak management and disease prevention guidelines. Atlanta, GA: U.S. Dept. of Health and Human Services, Centers for Disease Control and Prevention, 2011.
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(Editor), U. Desselberger, and J. Gray (Editor), eds. Viral Gastroenteritis, Volume 9 (Perspectives in Medical Virology). Elsevier Science, 2003.
Find full textBook chapters on the topic "Caliciviridae Infections"
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Guix, Susana, and Mary K. Estes. "Caliciviridae and Astroviridae." In Cellular Signaling and Innate Immune Responses to RNA Virus Infections, 389–402. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555815561.ch24.
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Madeley, Charles Richard. "Unclassified Viruses and Caliciviridae: Other Viruses Associated with Gastroenteritis." In Laboratory Diagnosis of Infectious Diseases Principles and Practice, 806–18. New York, NY: Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4612-3900-0_41.
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Rani, Manisha, Sushma Rajyalakshmi, Sunitha Pakalapaty, and Nagamani Kammilli. "Norovirus Structure and Classification." In Norovirus. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.98216.
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Norovirus are a major cause of acute gastroenteritis worldwide. Diarrheal disease is now the fourth common cause of mortality children under the age of 5 years but remain the 2nd most cause of morbidity. NoV are associated with 18% diarrheal diseases worldwide where rotavirus vaccinations has been successfully introduced. NoV has become major cause of gastroenteritis in children. NoV belong to family caliciviridae. They are non-enveloped, single stranded positive sense RNA Viruses. The genome consists of 3 Open reading frames, ORF-1 codes for non-structural protein, ORF-2 codes for major capsid protein VP1 and ORF-3 for minor capsid protein VP2. Based on sequence difference of the capsid gene (VP1), NoV have been classified in to seven genogroup GI-GVII with over 30 genotypes. Genogroups I, II, IV are associated with human infection. Despite this extensive diversity a single genotype GII.4 has been alone to be the more prevalent. Basic epidemiological disease burden data are generated from developing countries. NoV are considered fast evolving viruses and present an extensive diversity that is driven by acquisition of point mutations and recombinations. Immunity is strain or genotype specific with little or no protection conferred across genogroups. Majority of outbreaks and sporadic norovirus cases worldwide are associated with a single genotype, GII.4 which was responsible for 62% of reported NoV outbreaks in 5 continents from 2001 to 2007. GII.4 variants have been reported as major cause of global gastroenteritis pandemics starting in 1995 frequent emergence of novel GII.4 variants is known to be due to rapid evolution and antigenic variation in response to herd immunity. Novel GII.4 variants appear almost every 2 years. Recent GII.4 variant reported include Lordsdale 1996, Farmington Hills 2002, Hunter 2004, Yerseke 2006a, Den Haag 2006b, Apeldoon 2007, New Orleans 2009,most recently Sydney 2012. Detailed molecular epidemiologic investigation of NoV is associated for understanding the genetic diversity of NoV strain and emergence of novel NoV variants. However, reports have revealed that not all individuals develop symptoms and a significant proportion remains asymptomatic after NoV infections.