RESUMO
BACKGROUND: Chronic norovirus infection (CNI) causes significant morbidity in immunocompromised patients. No effective prevention or treatment currently exists. METHODS: Two patients with inborn errors of immunity, X- linked severe combined immunodeficiency (X-SCID) and DOCK8 deficiency, were followed longitudinally for clinical course, immune reconstitution, norovirus-specific T cell (NST) response, B cell reconstitution, and norovirus-specific antibody production. Samples were obtained in the peri-hematopoietic stem cell transplant setting (HSCT) before and after CNI clearance. The norovirus strain causing CNI was followed longitudinally for norovirus stool viral loads and sequencing. RESULTS: The noroviruses were identified as GII.4 Sydney[P4 New Orleans] in one patient and GII.17[P17] in the other. An exacerbation of diarrhea post-HSCT in the patient with X-SCID was consistent with norovirus infection but not with graft-vs-host-disease on pathologic samples. Both patients recovered polyfunctional NSTs in the CD4 and CD8 T cell compartments which recognized multiple norovirus structural and non-structural viral antigens. T cell responses were minimal during active CNI but detectable after resolution. Mapping of norovirus-specific T cell responses between the patient with DOCK8 and his matched sibling donor were nearly identical. B cell reconstitution or new endogenous antibody production for IgA or IgG were not observed. CONCLUSION: This report is the first to demonstrate reconstitution of norovirus-specific T cell immunity after HSCT closely temporally aligned with clearance of CNI suggesting that cellular immunity is sufficient for norovirus clearance.
RESUMO
An individual virion was long believed to act as an independent infectious unit in virology, until the recent discovery of vesicle-cloaked virus clusters which has greatly challenged this central paradigm. Vesicle-cloaked virus clusters (also known as viral vesicles) are phospholipid-bilayer encapsulated fluid sacs that contain multiple virions or multiple copies of viral genomes. Norovirus is a global leading causative agent of gastroenteritis, and the reported prevalence of vesicle-cloaked norovirus clusters in stool has raised concerns whether the current disinfection, sanitation, and hygiene practices can effectively control environmental pollution by these pathogenic units. In this study, we have demonstrated that vesicle-cloaked murine norovirus (MNV-1) clusters were highly persistent under temperature variation (i.e., freeze-thaw) and they were partially resistant to detergent decomposition. MNV-1 vesicles were 1.89-3.17-fold more infectious in vitro than their free virus counterparts. Most importantly, MNV-1 vesicles were up to 2.16-times more resistant to UV254 disinfection than free MNV-1 at a low viral load in vitro. Interestingly, with the increase of the viral load, free MNV-1 and MNV-1 vesicles showed equivalent resistance to UV254 disinfection. We show that the increased multiplicity of infection provided by vesicles is in part responsible for these attributes. Our study, for the first time, sheds light on the environmental behavior of vesicle-cloaked virus clusters as unique emerging pathogenic units. Our study highlights the need to revisit current paradigms of disinfection, sanitation, and hygiene practices for protecting public health.
Assuntos
Infecções por Caliciviridae , Norovirus , Animais , Desinfecção , Fezes , CamundongosRESUMO
Norovirus (NoV) and sapovirus (SaV) are recognized as the causative agents of acute gastroenteritis, and NoV is one of the leading pathogens reported worldwide. This study reports on the distribution of NoV and SaV genotypes in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand, from January 2015 to February 2017. From a total of 843 stool samples, 170 (20.2%) and 16 (1.9%) were identified as having NoV and SaV infections, respectively. Two samples (0.2%) were positive for both NoV and SaV. Of these, NoV GII.4 (57.2%) was the dominant genotype, followed by GII.2, GII.3, GII.17, GII.6, GII.7, GII.13, GII.14, GII.15, GII.21, GI.6, and GI.5. Among the NoV GII.4 variants, Sydney 2012 was the dominant variant during the period 2015-2016, while the other variants detected in this study were Asia 2003 and New Orleans 2009. Interestingly, an increase of NoV GII.2 was observed in 2016 and 2017. Characterization of partial RNA-dependent RNA polymerase and VP1 nucleotide sequences of GII.2 strains revealed that more than half of the GII.2 strains circulating in 2016 and 2017 were recombinant strains of GII.P16/GII.2. For SaV, the majority of strains belonged to GI.1 (55.6%) and GI.2 (33.3%), while GII.5 accounted for 11.1%. In conclusion, this study demonstrates the diversity of NoV and SaV, and the emergence of NoV GII.P16/GII.2 recombinant strains in 2016 and 2017 in Chiang Mai, Thailand.
Assuntos
Infecções por Caliciviridae/virologia , Doenças Transmissíveis Emergentes/virologia , Genótipo , Norovirus/genética , Recombinação Genética , Sapovirus/genética , Adolescente , Infecções por Caliciviridae/epidemiologia , Criança , Pré-Escolar , Doenças Transmissíveis Emergentes/epidemiologia , Fezes/virologia , Feminino , Hospitalização , Humanos , Lactente , Masculino , Epidemiologia Molecular , Norovirus/classificação , Norovirus/isolamento & purificação , Estudos Prospectivos , Sapovirus/classificação , Sapovirus/isolamento & purificação , Tailândia/epidemiologiaRESUMO
Enterovirus D68 (EV-D68) has been recognized as an important cause of acute respiratory infections. Here we report the molecular epidemiology of EV-D68 in Philippines from 2013 to 2014; we found cases in areas affected by Typhoon Haiyan and found new strains in the country.
Assuntos
Infecções por Enterovirus/epidemiologia , Infecções por Enterovirus/virologia , Enterovirus/classificação , Enterovirus/isolamento & purificação , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Pré-Escolar , Análise por Conglomerados , Feminino , Genótipo , Humanos , Incidência , Lactente , Masculino , Epidemiologia Molecular , Dados de Sequência Molecular , Filipinas/epidemiologia , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
Saffold virus (SAFV) is a newly discovered human virus which is classified into the genus Cardiovirus of the family Picornaviridae. A total of 608 fecal specimens collected during January 2012 to December 2013 from children with diarrhea in Chiang Mai, Thailand were investigated for SAFV by RT-nested PCR and sequence analysis. Of these, nine out of 608 (1.5%) were positive for SAFVs and four genotypes were identified, SAFV1, SAFV2, SAFV3, and SAFV4. SAFV mono-infection was found in five cases (CMH-S038-12, CMH-S071-12, CMH-S102-12, CMH-N029-12, and CMH-S048-13), while co-infection with other viruses causing diarrhea was observed in four cases (CMH-S021-12, CMH-S115-12, CMH-N048-13 and CMH-N103-13). This study provides more information about the genetic background of SAFV circulating in pediatric patients with diarrhea in Thailand.
Assuntos
Infecções por Cardiovirus/epidemiologia , Infecções por Cardiovirus/virologia , Diarreia/epidemiologia , Diarreia/virologia , Theilovirus/isolamento & purificação , Adolescente , Criança , Pré-Escolar , Análise por Conglomerados , Coinfecção/epidemiologia , Coinfecção/virologia , Fezes/virologia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Homologia de Sequência , Tailândia/epidemiologiaRESUMO
Two novel G3P[4] rotavirus strains were detected from children with acute diarrhea in Sendai, Japan, identified as a G3-P[4]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genotype constellation by whole-genome sequence analysis. The VP7 gene of the two strains displayed the highest nucleotide sequence identity (91 %) and showed a close genetic relationship (99 % bootstrap value) to an equine rotavirus reported in India. The other gene segments were related to human group A rotaviruses. This report suggests a possible reassortment event between human and equine rotaviruses.
Assuntos
RNA Viral/genética , Vírus Reordenados/genética , Vírus Reordenados/isolamento & purificação , Infecções por Rotavirus/virologia , Rotavirus/genética , Rotavirus/isolamento & purificação , Animais , Antígenos Virais/genética , Proteínas do Capsídeo/genética , Pré-Escolar , Análise por Conglomerados , Diarreia/epidemiologia , Diarreia/virologia , Feminino , Cavalos , Humanos , Lactente , Japão/epidemiologia , Masculino , Dados de Sequência Molecular , Filogenia , Infecções por Rotavirus/epidemiologia , Análise de Sequência de DNA , Homologia de Sequência de AminoácidosRESUMO
Norovirus (NoV) and Sapovirus (SaV) have been reported as a common cause of acute gastroenteritis worldwide. For a decade, surveillances of NoV and SaV have been conducted continually in Thailand. To monitor the epidemiological situation and to determine the genetic variation of NoV and SaV in Chiang Mai, Thailand, 567 samples collected from pediatric patients hospitalized with acute gastroenteritis were examined during 2007, and 2010-2011 by semi-nested RT-PCR and nucleotide sequencing methods. NoV was detected at 15.9%. Phylogenetic analysis revealed multiple NoV genotypes, GI/14 (1.1%), GII/1 (1.1%), GII/2 (1.1%), GII/3 (4.4%), GII/4 (65.6%), GII/6 (10.0%), GII/7 (2.2%), GII/12 (4.4%), GII/13 (3.3%), GII/16 (5.7%), and unclassified genotype (1.1%), circulating in this area. Among these, NoV GII/4 was the most prevalent genotype with a predominance of GII/4 2009 over other variants, 1996, 2006a, and 2006b. For SaV, the prevalence was 1.2% which was much lower than those of NoV and only SaV GI/1 was detected. This study highlights the epidemiology of NoV and SaV and genetic diversity of viruses circulating in pediatric patients hospitalized with acute gastroenteritis in Chiang Mai, Thailand.
Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Variação Genética , Norovirus/classificação , Sapovirus/classificação , Pré-Escolar , Feminino , Genótipo , Humanos , Lactente , Masculino , Dados de Sequência Molecular , Norovirus/genética , Norovirus/isolamento & purificação , Filogenia , Reação em Cadeia da Polimerase , Prevalência , Sapovirus/genética , Sapovirus/isolamento & purificação , Análise de Sequência de DNA , Tailândia/epidemiologiaRESUMO
Norovirus infection can cause gastrointestinal disease in humans. Development of therapies and vaccines against norovirus have been limited by the lack of a suitable and reliable animal model. Here we established rhesus macaques as an animal model for human norovirus infection. We show that rhesus macaques are susceptible to oral infection with human noroviruses from two different genogroups. Variation in duration of virus shedding (days to weeks) between animals, evolution of the virus over the time of infection, induction of virus-specific adaptive immune responses, susceptibility to reinfection and preferential replication of norovirus in the jejunum of rhesus macaques was similar to infection reported in humans. We found minor pathological signs and changes in epithelial cell surface glycosylation patterns in the small intestine during infection. Detection of viral protein and RNA in intestinal biopsies confirmed the presence of the virus in chromogranin A-expressing epithelial cells, as it does in humans. Thus, rhesus macaques are a promising non-human primate model to evaluate vaccines and therapeutics against norovirus disease.
Assuntos
Infecções por Caliciviridae , Norovirus , Vacinas , Humanos , Animais , Macaca mulatta , Intestino DelgadoRESUMO
BACKGROUND: Norovirus (NoV) is recognized as a significant cause of acute gastroenteritis in infants and young children worldwide. This study investigated the prevalence of NoV infection in hospitalized children with gastroenteritis in Chiang Mai, Thailand in 2006. METHODS: A total of 156 fecal specimens were collected from children with diarrhea admitted to McCormick Hospital in 2006. All fecal specimens were examinedffor NoV by RT-PCR and the genotypes were identified by sequence analysis. RESULTS: A high prevalence of NoV infection was detected (20.5%, 32/156). NoV GII/4 was the most predominant genotype with a prevalence of 87.5% (28/32), while GII/3, GII/6, GII/12, and GII/15 were less common (3.1% each). Among GII/4 strains, 2006b variant (75%, 21/28) emerged as the leading strain and dominated over the Hunter'04-like variant, which was the most common strain in the previous season of 2005. In addition, the 2003, 2004, and 2006a variants were also detected. NoV infections were most commonly observed in the rainy season in Thailand. CONCLUSIONS: This study demonstrated the emergence of GII/4 2006b variants as the major pathogen causing acute gastroenteritis among infants and children at the age of less than 5 years old who admitted to hospital in Chiang Mai, Thailand in 2006. Additionally, other GII/4 variants of 2003, 2004, and 2006a were also reported.
Assuntos
Gastroenterite/epidemiologia , Norovirus/isolamento & purificação , Criança , Fezes/virologia , Gastroenterite/virologia , Hospitalização , Humanos , Norovirus/classificação , Norovirus/genética , Tailândia/epidemiologiaRESUMO
Noroviruses are a major cause of acute gastroenteritis worldwide and can establish chronic infection in immunocompromised individuals. To investigate the mechanisms of norovirus evolution during chronic infection, we selected seven representative patients from a National Institutes of Health study cohort who sustained norovirus infection for periods ranging from 73 to 1,492 days. Six patients shed viruses belonging to a single genotype (GII.2[PNA], GII.4 New Orleans[P4], GII.4 Den Haag[P4], GII.3[P21], GII.6[P7], or GII.14[P7]) over the period examined, while one patient sequentially shed two genotypes (GII.6[P7] followed by GII.4 Sydney[P31]). Norovirus genomes from consecutive stool samples were sequenced at high resolution (>3,300 reads/nucleotide position) using the Illumina platform and subjected to bioinformatics analysis. Norovirus sequences could be resolved into one or more discrete clonal RNA genomes that persisted within these patients over time. Phylogenetic analyses inferred that clonal populations originated from a single founder virus and not by reinfection with community strains. Estimated evolutionary rates of clonal populations during persistent infection were similar to those of noroviruses from acute infection in the global database, suggesting that inherently higher RNA-dependent polymerase error rates were not associated with the ability to persist. The high-resolution analysis of norovirus diversity and evolution at the population level described here should allow a better understanding of adaptive mutations sustained during chronic infection. IMPORTANCE Noroviruses are an important cause of chronic diarrhea in patients with compromised immune systems. Presently, there are no effective therapies to clear the virus, which can persist for years in the intestinal tract. The goal of our study was to develop a better understanding of the norovirus strains that are associated with these long-term infections. With the remarkable diversity of norovirus strains detected in the immunocompromised patient cohort we studied, it appears that most, if not all, noroviruses circulating in nature may have the capacity to establish a chronic infection when a person is unable to mount an effective immune response. Our work is the most comprehensive genetic data set generated to date in which near full-length genomes from noroviruses associated with chronic infection were analyzed by high-resolution next-generation sequencing. Analysis of this data set led to our discovery that certain patients in our cohort were shedding noroviruses that could be subdivided into distinct haplotypes or populations of viruses that were co-evolving independently. The ability to track haplotypes of noroviruses during chronic infection will allow us to fine-tune our understanding of how the virus adapts and maintains itself in the human host, and how selective pressures such as antiviral drugs can affect these distinct populations.
RESUMO
Acute gastroenteritis caused by human noroviruses (HuNoVs) is a significant global health and economic burden and is without licensed vaccines or antiviral drugs. The GII.4 HuNoV causes most epidemics worldwide. This virus undergoes epochal evolution with periodic emergence of variants with new antigenic profiles and altered specificity for histo-blood group antigens (HBGA), the determinants of cell attachment and susceptibility, hampering the development of immunotherapeutics. Here, we show that a llama-derived nanobody M4 neutralizes multiple GII.4 variants with high potency in human intestinal enteroids. The crystal structure of M4 complexed with the protruding domain of the GII.4 capsid protein VP1 revealed a conserved epitope, away from the HBGA binding site, fully accessible only when VP1 transitions to a "raised" conformation in the capsid. Together with dynamic light scattering and electron microscopy of the GII.4 VLPs, our studies suggest a mechanism in which M4 accesses the epitope by altering the conformational dynamics of the capsid and triggering its disassembly to neutralize GII.4 infection.
Assuntos
Antígenos de Grupos Sanguíneos , Infecções por Caliciviridae , Norovirus , Humanos , Proteínas do Capsídeo/química , Capsídeo/metabolismo , Norovirus/genética , Sítios de Ligação , Epitopos/metabolismo , Antígenos de Grupos Sanguíneos/metabolismoRESUMO
Human astrovirus (HAstV) is one of the causative agents of acute gastroenteritis in children worldwide. The objective of this study was to elucidate the molecular epidemiology and genotypic diversity of HAstV circulating in pediatric patients admitted to hospital with diarrhea in Thailand during the year 2000-2011, except for 2004, 2006, and 2009. A total of 1,022 fecal specimens were tested for HAstV by reverse transcription polymerase chain reaction (RT-PCR). HAstV was detected at 1.4% (14 of 1,022). All HAstV strains detected in this study were characterized further by nucleotide sequencing and phylogenetic analysis. Analysis of 348 bp partial capsid nucleotide sequences revealed that HAstV strains detected were HAstV-1 (1a, 1b, and 1d) (8 strains), HAstV-2 (2c) (3 strains), HAstV-3 (1 strain), and HAstV-5 (2 strains). HAstV-1, the most predominant genotype was detected initially in 2002 and circulated continuously up to 2011. HAstV-2 was detected in year 2001, and 2007 and grouped into a 2c lineage. HAstV-3 was found only in 2000 and HAstV-5 was found in the year 2001. The findings indicate that a wide variety of HAstV strains continue to circulate in children admitted to hospital with acute gastroenteritis in Thailand over a decade. The data provide an epidemiological overview of HAstV infection and HAstV genotype distribution in Thailand.
Assuntos
Infecções por Astroviridae/epidemiologia , Gastroenterite/epidemiologia , Mamastrovirus/classificação , Mamastrovirus/genética , Infecções por Astroviridae/virologia , Proteínas do Capsídeo/genética , Pré-Escolar , Análise por Conglomerados , Fezes/virologia , Feminino , Gastroenterite/virologia , Genótipo , Humanos , Lactente , Masculino , Mamastrovirus/isolamento & purificação , Epidemiologia Molecular , Dados de Sequência Molecular , Filogenia , Prevalência , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Tailândia/epidemiologiaRESUMO
Human cosavirus (HCoSV) is a newly discovered virus in Picornaviridae family. At present it is not clear whether HCoSV is associated with diseases, including gastroenteritis in humans, as epidemiological data is limited. Epidemiological surveillance of HCoSV was conducted on 150 fecal specimens collected from children and 150 samples from adults with diarrhea in Thailand by RT-PCR screening. HCoSV was found in a single adult specimen and not in any of the fecal specimens from children. This represents the first report of HCoSV infection in patients with diarrhea in Thailand. Extensive epidemiological surveillance of novel viruses associated with diarrhea in other populations may provide a better understanding of the distribution, genetic diversity, and association of the viral agents associated with acute gastroenteritis in humans.
Assuntos
Diarreia/epidemiologia , Diarreia/virologia , Infecções por Picornaviridae/epidemiologia , Infecções por Picornaviridae/virologia , Picornaviridae/classificação , Picornaviridae/isolamento & purificação , Adulto , Criança , Pré-Escolar , Fezes/virologia , Humanos , Programas de Rastreamento/métodos , Dados de Sequência Molecular , Picornaviridae/genética , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Análise de Sequência de DNA , Tailândia/epidemiologiaRESUMO
BACKGROUND: Viral gastroenteritis has been recognized as one of the most common illnesses that affects infants and young children all over the world. A wide variety of viruses associated with the disease are continually being reported. To investigate the epidemiological situation of diarrhea virus infection in Chiang Mai, Thailand, surveillance was conducted during January to December 2007. METHODS: A total of 160 fecal specimens collected from pediatric patients admitted to the hospital with acute gastroenteritis were tested for the presence of group A, B, and C rotaviruses, norovirus, sapovirus, astrovirus, adenovirus, Aichi virus, enterovirus, bocavirus, and human parechovirus by RT-multiplex PCR. RESULTS: Of 160 fecal specimens tested, 85 (53.1%) were positive for diarrhea viruses. Of these, group A rotavirus was the predominant with a prevalence of 27.5%, followed by norovirus GII (11.9%), sapovirus (3.1%), enterovirus (2.5%), human parechovirus (1.9%), and norovirus GI, astrovirus, adenovirus (each 0.6%). Mixed-infections of 2 or 3 viruses were observed in 7 (4.4%) patients. However, none of groups B and C rotaviruses and Aichi virus were detected in this study. Monthly distribution analysis revealed that all those diarrhea viruses were detected continually throughout the year at a low level of infection except for group A rotavirus and norovirus infections which appeared to peak in a cool season in January-March and December, respectively. CONCLUSIONS: This surveillance revealed a wide variety of diarrhea viruses currently circulating in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand.
Assuntos
Diarreia Infantil/virologia , Gastroenterite/virologia , Infecções por Vírus de RNA/virologia , Vírus de RNA/isolamento & purificação , Doença Aguda , Pré-Escolar , Diarreia Infantil/epidemiologia , Fezes/virologia , Gastroenterite/epidemiologia , Humanos , Lactente , Infecções por Vírus de RNA/epidemiologia , RNA Viral/análise , Tailândia/epidemiologia , Fatores de TempoRESUMO
Enteric caliciviruses, including noroviruses (NoVs) and sapoviruses (SaVs), are recognized as important etiologic agents of acute gastroenteritis with considerable genetic diversity. In this study, fecal specimens collected from 147 infants and young children admitted to hospital with acute gastroenteritis in 2005 in Chiang Mai, Thailand, were screened for NoVs and SaVs by reverse transcription-multiplex polymerase chain reaction (RT-multiplex PCR). Ten isolates (6.8%) belonged to NoV GII genogroup and five (3.4%) were positive for SaVs. GII/4 was the most predominant genotype of NoVs, followed by GII/15, GII/6, and GII/12. Surprisingly, NoVs GII/1, GII/2, GII/3, GII/7, and GII/16 genotypes, which were detected previously during the 2002-2004 survey, were not detected in 2005. Conversely, NoVs GII/6, GII/12, and GII/15 appeared in 2005 but were not detected during the 2002-2004 survey. The only genotype found to be common, as the most predominant genotype, in both surveys was NoV GII/4. Similar findings were also observed for SaVs, that is, the GI/2 and GIV detected during 2002-2004 were not detected in 2005, while GI/5 and GII/3 detected in 2005 were not detected previously during the 2002-2004 surveillance. In addition, comprehensive genetic evolutionary analysis of NoV GII/4 genotype demonstrated that the majority of GII/4 detected in this study (CMH002/05, CMH005/05, CMH042/05, and CMH083/05) were classified as new NoV variants and fell into subtype GII/4-d (Hunter'04-like cluster). Only one NoV GII/4 strain (CMH142/05) belonged to subtype GII/4-e. The data indicated heterogeneity and highly dynamic genotypic distribution of NoVs and SaVs circulating in children admitted to hospital with acute gastroenteritis in Chiang Mai, Thailand.
Assuntos
Infecções por Caliciviridae/virologia , Gastroenterite/virologia , Norovirus/classificação , Norovirus/genética , Polimorfismo Genético , Sapovirus/classificação , Sapovirus/genética , Infecções por Caliciviridae/epidemiologia , Pré-Escolar , Análise por Conglomerados , Diarreia/epidemiologia , Diarreia/virologia , Fezes/virologia , Feminino , Gastroenterite/epidemiologia , Genótipo , Hospitais , Humanos , Lactente , Recém-Nascido , Masculino , Epidemiologia Molecular , Dados de Sequência Molecular , Norovirus/isolamento & purificação , Filogenia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sapovirus/isolamento & purificação , Análise de Sequência de DNA , Tailândia/epidemiologiaRESUMO
Norovirus (NoV) is a causative agent of gastroenteritis in children and adults worldwide. Although reverse transcription-polymerase chain reaction (RT-PCR) has been accepted as the standard method for diagnosis of NoV infection, it requires well-trained personnel and sophisticated equipments. Performance of a commercial immunochromatography (IC) test for rapid detection of NoV was evaluated with fecal specimens collected from children admitted to a hospital with acute gastroenteritis during 2005-2007 in Chiang Mai, Thailand. A total of 463 fecal specimens were tested for the presence of NoV by a commercial immunochromatography kit (IP-NoV) and by RT-PCR. Sensitivity, specificity, and agreement of immunochromatography as compared to RT-PCR were 74.2%, 99.5%, and 96.1%, respectively. Based on the NoV genotypes determined by phylogenetic analysis, immunochromatography detected NoV GII/3, GII/4, GII/6, GII/13, GII/15, and GII/16 genotypes. The findings indicate that the immunochromatography kit could be used for a direct detection of NoV GII in clinical specimens and covering a wide range of NoV genotypes circulating in Thailand.
Assuntos
Infecções por Caliciviridae/virologia , Cromatografia/métodos , Fezes/virologia , Gastroenterite/virologia , Imunoensaio/métodos , Norovirus/isolamento & purificação , Infecções por Caliciviridae/diagnóstico , Pré-Escolar , Diarreia/diagnóstico , Diarreia/virologia , Gastroenterite/diagnóstico , Humanos , Norovirus/classificação , Norovirus/genética , Kit de Reagentes para Diagnóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade , Tailândia/epidemiologiaRESUMO
Human noroviruses are a major cause of diarrheal illness, but pathogenesis is poorly understood. Here, we investigate the cellular tropism of norovirus in specimens from four immunocompromised patients. Abundant norovirus antigen and RNA are detected throughout the small intestinal tract in jejunal and ileal tissue from one pediatric intestinal transplant recipient with severe gastroenteritis. Negative-sense viral RNA, a marker of active viral replication, is found predominantly in intestinal epithelial cells, with chromogranin A-positive enteroendocrine cells (EECs) identified as a permissive cell type in this patient. These findings are consistent with the detection of norovirus-positive EECs in the other three immunocompromised patients. Investigation of the signaling pathways induced in EECs that mediate communication between the gut and brain may clarify mechanisms of pathogenesis and lead to the development of in vitro model systems in which to evaluate norovirus vaccines and treatment.
Assuntos
Células Enteroendócrinas/imunologia , Células Epiteliais/imunologia , Norovirus/fisiologia , Doença Aguda , District of Columbia , Células Enteroendócrinas/metabolismo , Gastroenterite/virologia , Genótipo , Humanos , Intestino Delgado/patologia , Intestino Delgado/virologia , Norovirus/genética , RNA Viral , Replicação ViralRESUMO
The 5' untranslated region (UTR) of the RNA genomes of enteroviruses possesses an internal ribosome entry site (IRES) that directs translation of the mRNA by binding to ribosomes. Infection with enterovirus D68 causes respiratory symptoms and is sometimes associated with neurological disorders. The number of reports of the viral infection and neurological disorders has increased in 2010s, although the reason behind this phenomenon remains unelucidated. In this study, we investigated the evolutionary and functional diversity of the 5' UTR of recently circulating strains of the virus. Genomic sequences of 374 viral strains were acquired and subjected to phylogenetic analysis. The IRES activity of the viruses was measured using a luciferase reporter assay. We found a highly conserved sequence in the 5' UTR and also identified the location of variable sites in the predicted RNA secondary structure. IRES activities differed among the strains in some cell lines, including neuronal and respiratory cells, and were especially high in strains of a major lineage from the recent surge. The effect of mutations in the 5' UTR should be studied further in the future for better understanding of viral pathogenesis.