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1.
BMC Infect Dis ; 19(1): 1021, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31791261

RESUMO

BACKGROUND: Currently, norovirus (NoV) is associated with one-fifth of all acute gastroenteritis (AGE) cases worldwide. The NoV GII.17_2014 variant has been associated with gastroenteritis outbreaks in several Asian countries, replacing the previously dominant Sydney 2012 variant. There is limited data about circulation of this new strain in Brazil. This study aimed to describe the phylogenetic and evolutionary characteristics of the GII.17_2014 strains in the Northern region of Brazil. METHODS: NoV was detected by enzyme immunoassay (EIA) in 645 stool samples of AGE cases that were reported in Pará and Amazonas states during 2015-2016. All positive samples were tested for NoV GI and GII by reverse transcription polymerase chain reaction (RT-PCR) and the amplicons were subjected to genome sequencing. The GII.17-positive samples were retested by PCR using different sets of designed primers, which target a highly conserved capsid gene region. Next, the amplicons were sequenced and phylogenetically analyzed using Bayesian inferences. RESULTS: Of the 645 samples tested, 208 (32.2%) tested were positive for NoV by EIA, among which 95 (45.7%) were genotyped. Among the genotyped samples, 12 (12.6%) were characterized as GII.17_2014 with the first case detected in November 2015 (1/30, 3.3%) and the others in 2016 (11/65, 16.9%). All strains found in our study were clustered in clade D (epidemic strain). The uncorrelated log-normal model estimations calculated the rate of evolution for GII-17 strains as 1.95 × 10- 3 (1.28 × 10- 3-2.63 × 10- 3). In total, 36 nucleotide changes were observed after analyzing the VP1 sequence, among which 28 occurred in the P2 region. CONCLUSIONS: These data demonstrate the evolutionary dynamics in NoV GII.17_2014 strains, which indicated high mutation rates with nucleotide substitutions and indels that are related to the elevated levels of antigenic diversity. This partly explains the increase in viral prevalence.


Assuntos
Infecções por Caliciviridae/virologia , Evolução Molecular , Gastroenterite/virologia , Tipagem Molecular , Norovirus/classificação , Norovirus/genética , Brasil/epidemiologia , Infecções por Caliciviridae/epidemiologia , Proteínas do Capsídeo/genética , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Surtos de Doenças , Epidemias , Fezes/virologia , Gastroenterite/epidemiologia , Genótipo , Humanos , Tipagem Molecular/métodos , Filogenia , Prevalência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Virologia/métodos
2.
Vet Microbiol ; 237: 108361, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31521392

RESUMO

Rabbit hemorrhagic disease (RHD) is a highly infectious disease in European rabbits (Oryctolagus cuniculus), caused by a virus belonging to the genus Lagovirus (RHDV; family Caliciviridae). In 2010, a new genotype of RHDV (RHDV2 or RHDVb, currently designated GI.2) emerged in France, affecting both domestic rabbits, even those vaccinated for the classical RHDV genotypes (currently designated GI.1) and wild rabbits. GI.2 was subsequently identified in other European countries. The aim of the present study was to monitor the GI.2 epidemic in wild rabbits in Andalusia (southern Spain) during the period 2013-2017. At the beginning of summer 2013, high mortalities were detected in wild rabbit populations in southern Spain. A total of 96 affected hunting or protected areas were surveyed. The first outbreak was observed on June 2013. The number of outbreaks sharply increased in 2013 and 2014, with a decreasing trend being observed during the following years. The spatial distribution of GI.2 was not homogeneous, since most of the detected outbreaks were concentrated in the western part of Andalusia. The outbreaks peaked in winter and spring and have been detected in the last five consecutive years, which suggests endemic circulation of GI.2 in wild rabbit populations in Spain. A total of 190 dead rabbits from 87 of the 96 areas surveyed were collected during the study period. Mortality affected rabbits of different age classes, including kittens. RT-PCR confirmed the presence of GI.2 RNA in the livers of 185 of the 190 (97.4%) rabbits. Phylogenetic analysis performed on eleven samples collected in different provinces of Andalusia between 2013 and 2017, showed high nucleotide identity with GI.2 strains Spain, France and Portugal. The results constitute an important step in understanding of the emergence and spread of GI.2 in this country and will provide valuable information for the development of surveillance programs in Europe.


Assuntos
Animais Selvagens , Infecções por Caliciviridae/veterinária , Epidemias/veterinária , Vírus da Doença Hemorrágica de Coelhos , Coelhos/virologia , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Doenças Transmissíveis Emergentes/veterinária , Doenças Transmissíveis Emergentes/virologia , Filogenia , RNA Viral/genética , RNA Viral/isolamento & purificação , Espanha/epidemiologia
3.
Acta Virol ; 63(3): 328-332, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507200

RESUMO

Acute gastroenteritis (AGE) is one of the most frequently occuring illnesses in children and adults worldwide. In February 2017, two AGE outbreaks occurred in two adjacent schools in Huzhou city, Zhenjiang province of China. We detected high percentages of recombinant norovirus GII.P16/GII.2 in one school and chicken anemia virus (CAV) in another school using next generation sequencing (NGS) and specific PCR. The results highlight the importance of continuous surveillance of GII.P16/GII.2, and suggest the need of further studies on whether CAV causes AGE. Keywords: acute gastroenteritis; norovirus; chicken anemia virus; Huzhou; School.


Assuntos
Infecções por Caliciviridae , Vírus da Anemia da Galinha , Surtos de Doenças , Gastroenterite , Norovirus , Infecções por Caliciviridae/diagnóstico , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Criança , China/epidemiologia , Infecções por Circoviridae/epidemiologia , Gastroenterite/diagnóstico , Gastroenterite/epidemiologia , Gastroenterite/virologia , Humanos , Prevalência
4.
PLoS Pathog ; 15(9): e1008009, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31536612

RESUMO

Human noroviruses (HuNoVs) are the most common cause of foodborne illness, with a societal cost of $60 billion and 219,000 deaths/year. The lack of robust small animal models has significantly hindered the understanding of norovirus biology and the development of effective therapeutics. Here we report that HuNoV GI and GII replicate to high titers in zebrafish (Danio rerio) larvae; replication peaks at day 2 post infection and is detectable for at least 6 days. The virus (HuNoV GII.4) could be passaged from larva to larva two consecutive times. HuNoV is detected in cells of the hematopoietic lineage and the intestine, supporting the notion of a dual tropism. Antiviral treatment reduces HuNoV replication by >2 log10, showing that this model is suited for antiviral studies. Zebrafish larvae constitute a simple and robust replication model that will largely facilitate studies of HuNoV biology and the development of antiviral strategies.


Assuntos
Norovirus/fisiologia , Norovirus/patogenicidade , Replicação Viral/fisiologia , Peixe-Zebra/virologia , Animais , Antivirais/administração & dosagem , Infecções por Caliciviridae/virologia , Doenças Transmitidas por Alimentos/virologia , Gastroenterite/virologia , Interações entre Hospedeiro e Microrganismos , Humanos , Larva/virologia , Metagenômica , Modelos Animais , Norovirus/genética , Cultura de Vírus/métodos , Replicação Viral/efeitos dos fármacos
5.
Vet Microbiol ; 236: 108388, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31500726

RESUMO

Neboviruses (NeVs) is an important causative agent of calf diarrhea. Here, 354 diarrhoeic samples were collected from yak on 55 farms in the Qinghai-Tibet Plateau, China. 22.0% of the diarrhoeic samples were detected as NeVs-positive by RT-PCR assay. Phylogenetic analysis of 78 NeVs RdRp fragments showed that 69 strains were closely related to NB-like strains, and the remaining 9 strains were clustered into an independent branch, which may represent a novel RdRp genotype. Two complete NeVs genomes (YAK/NRG-17/17/CH and YAK/HY1-2/18/CH) were successfully sequenced with 7459 nt and 7460 nt in length, respectively. The genomes of the two strains only shared 68.1%-69.3% nt identity with all six known NeVs genomes, and phylogenetic trees based on its genome, VP1, RdRp, VP2, P34, NTPase, P30, VPg and 3CLpro proteins suggested that the two strains may represent a novel NeVs strain with novel VP1 genotype and novel RdRp genotype. Notably, 11.5% NeVs strains were screened as the novel NeVs strains based VP1 and RdRp sequences. These novel NeVs strains were detected from 6 farms in two counties, indicating that the novel NeVs has spread in local region. To best of our knowledge, this is the first detection of NeVs in yak. Moreover, a novel NeVs strain was identified based on complete genome. These results contribute to further understand the prevalence and genetic evolution of NeVs.


Assuntos
Infecções por Caliciviridae/veterinária , Caliciviridae/isolamento & purificação , Doenças dos Bovinos/virologia , Genoma Viral , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Bovinos , China/epidemiologia , Diarreia/veterinária , Diarreia/virologia , Filogenia
6.
BMC Vet Res ; 15(1): 311, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31477115

RESUMO

BACKGROUND: Norovirus (NoV) is recognized as a highly contagious enteric pathogen of mammals, and bovine norovirus (BNoV) is associated with calf diarrhoea and has caused great economic losses in the cattle industry. RESULTS: Here, we describe a case of emerging calf diarrhoea on a cattle farm in Henan Province, Central China. BNoV was the only enteric pathogen detected in outbreaks according to tests for enteric viruses, bacteria and parasites. The complete genome of the newly identified strain CH-HNSC-2018 was successfully sequenced and found to be 7342 nucleotides in length. Sequence and phylogenetic analyses revealed that CH-HNSC-2018 belongs to GIII.2 BNoV. Further analysis of the major capsid protein demonstrated that it is separated by specific genetic distances from previous BNoV strains identified in China and has 4 new amino acid (aa) mutations, 134A, 327 T, 380 L and 423A, in the VP1 protein and 11 aa substitutions in the hypervariable P2 subdomain, suggesting that the BNoV strains circulating in China are diverse. CONCLUSIONS: This is the first detection of GIII.2 BNoV in the VP1 region in China. This report should form a basis for further molecular studies on NoV and bovine enteric viruses in China.


Assuntos
Infecções por Caliciviridae/veterinária , Doenças dos Bovinos/virologia , Diarreia/veterinária , Genótipo , Norovirus/isolamento & purificação , Filogenia , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Bovinos , China/epidemiologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/veterinária , Doenças Transmissíveis Emergentes/virologia , Diarreia/epidemiologia , Diarreia/virologia , Surtos de Doenças/veterinária , Norovirus/genética
7.
Emerg Infect Dis ; 25(9): 1730-1735, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31441758

RESUMO

Tools to detect human norovirus infectivity have been lacking. Using human intestinal enteroid cultures inoculated with GII.Pe-GII.4 Sydney-infected fecal samples, we determined that a real-time reverse transcription PCR cycle threshold cutoff of 30 may indicate infectious norovirus. This finding could be used to help guide infection control.


Assuntos
Infecções por Caliciviridae/epidemiologia , Norovirus/isolamento & purificação , Idoso , Infecções por Caliciviridae/virologia , China/epidemiologia , Fezes/virologia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Norovirus/genética , Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e Especificidade
8.
BMC Infect Dis ; 19(1): 736, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31438883

RESUMO

BACKGROUND: Noroviruses (NoVs) are considered an important cause of acute gastroenteritis (AGE) across all age groups, especially in children under 5 years of age. We investigated the epidemiology of noroviruses in outpatient children from the Children's Hospital of Fudan University in Shanghai, China. METHODS: Stool specimens were collected between January 2012 and December 2017 from 1433 children under 5 years of age with acute gastroenteritis. All samples were analysed by conventional reverse transcription-polymerase chain reaction (RT-PCR) for genogroup II NoVs amplifying both the RNA-dependent RNA polymerase (RdRp) and partial capsid genes. The Norovirus Genotyping Tool v.2.0 ( https://www.rivm.nl/mpf/typingtool/norovirus/ ) was used for genotyping the strains, and phylogenetic analyses were conducted by MEGA 6.0. RESULTS: From 2012 to 2017, GII NoVs were detected in 15.4% (220/1433) of the samples, with the highest detection rate in children aged 7-12 months (19.2%, 143/746). The seasons with the highest prevalence of GII NoVs infection were autumn and winter. Based on genetic analysis of RdRp, GII.Pe (74.5%%, 137/184) was the most predominant RdRp genotype from 2013 to 2017, while GII.P4 played a dominant role in 2012 (55.6%, 21/36). Among the capsid genotypes, the most prevalent NoV genotype from 2012 to 2017 was GII.4 (74.1%, 163/220). On the basis of genetic analysis of RdRp and capsid sequences, the strains were clustered into - 19 RdRp/capsid genotypes, and 12 of them were discordant, such as GII.Pe/GII.4-Sydney_2012, GII.P12/GII.3, GII.P7/GII.6, GII.Pe/GII.3, and GII.P16/GII.2. Starting with 2013, GII.Pe/GII.4-Sydney_2012 had completely replaced the pandemic GII.P4-2006b/GII.4-2006b subtype and was detected in children across all age groups. CONCLUSIONS: The present study shows high detection rates and the genetic diversity of circulating NoV GII genotypes in paediatric AGE samples from Shanghai. The findings emphasize the importance of continuous molecular surveillance of emerging NoV strains.


Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Variação Genética , Norovirus/classificação , Norovirus/genética , Doença Aguda , Proteínas do Capsídeo/genética , Pré-Escolar , China/epidemiologia , Feminino , Gastroenterite/patologia , Genótipo , Hospitais Pediátricos , Humanos , Lactente , Recém-Nascido , Masculino , Epidemiologia Molecular , Norovirus/isolamento & purificação , Filogenia , Prevalência , Estações do Ano
9.
BMC Infect Dis ; 19(1): 696, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387542

RESUMO

BACKGROUND: Human norovirus is regarded as the leading cause of nonbacterial acute diarrhea in developing and developed countries. Among all genotypes, GII.4 has been the predominant genotype, but in East Asia, it was replaced by the GII.17 in 2014/2015. However, after the prevalence of new GII.17 variant in South China, a sharply increase in the number of norovirus infections associated with sporadic acute diarrhea was detected. In this study, we would investigate the prevalence and genetic diversity of noroviruses in the sporadic acute gastroenteritis cases in the post-GII.17 period in South China. METHODS: Norovirus was screened from 217 patients with sporadic acute gastroenteritis from August 2015 to October 2017 by reverse transcription-polymerase chain reaction. Then, two regions including the partial RNA polymerase and the capsid gene of positive samples were amplified and sequenced. Phylogenetic analyses were performed to determine norovirus genotypes. Complete VP1 sequences of GII.4 strains detected in this study were also amplified and subjected into evolutionary tracing analyses. RESULTS: A total of 43 (19.82%) norovirus samples were confirmed from 217 stool specimens, and it was found that GII.4 resurged as the new predominant variant, accounting for 76.74% (33/43) of positive samples. Only one local strain GZ2015-L550 was clustered with the contemporary GII.P16/GII.4-2012 recombinant variant, and other 32 local strains belonged to the clade with the GII.Pe/GII.4-2012 variant. Other genotypes including GII.17 (n = 4), GII.3 (n = 4), GII.8 (n = 1) and GI. 6 (n = 1) were also detected. Furthermore, all GII.4 strains were phylogenetic analyzed based on their capsid P2 subdomains. Combined with other reported 754 strains, the GII.4-2012 variant could be divided into two clades. Most GII.4 strains collected in 2016 and 2017 in this study (7/8) formed a new cluster A in Clade II with additional 103 contemporaneous strains. In addition, evolutionary tracing of the capsid P2 subdomain of this variant was also analyzed, and one specific amino acid substitutions (N373) was identified for Cluster A. CONCLUSION: In summary, this study confirmed a norovirus infection peak in the post-GII.17 period in South China, which was caused by the resurgence of the GII.4 variant.


Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Norovirus/genética , Adolescente , Adulto , Substituição de Aminoácidos , Proteínas do Capsídeo/genética , Criança , Pré-Escolar , China/epidemiologia , Diarreia/epidemiologia , Diarreia/virologia , Fezes/virologia , Feminino , Variação Genética , Humanos , Masculino , Norovirus/patogenicidade , Filogenia , Prevalência
10.
Int J Infect Dis ; 88: 41-48, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31382046

RESUMO

BACKGROUND: Acute diarrhea is a leading cause of morbidity and mortality among children under five worldwide. As no published data is available on the occurrence of this infection in the Republic of Congo, this study aimed at (1) determining the prevalence and (2) characterizing genotypes of norovirus strains in Brazzaville. METHODS: From June 2012 to June 2013, stool samples were collected from hospitalized young children with acute gastroenteritis. A total of 545 samples were tested for GI and GII norovirus infections using nested duplex reverse-transcription-polymerase chain reaction and sequencing. RESULTS: The GI and GII norovirus infection were detected in 148 samples. Males (28%) were not significantly more infected than females (25%). Norovirus infection was found exclusively in children aged under 24 months with a higher prevalence (P=0,048) in the age group of 7-12 months, and throughout the year with a peak in August and September. Genetic diversity of norovirus strains revealed that GII was the most prevalent (87%). No risk factor was significantly associated with norovirus infection. CONCLUSION: This study showed that noroviruses are important agents responsible for acute diarrhea in Congolese children and highlights the importance of continued surveillance.


Assuntos
Infecções por Caliciviridae/epidemiologia , Diarreia/enzimologia , Gastroenterite/epidemiologia , Norovirus/isolamento & purificação , Doença Aguda , Infecções por Caliciviridae/virologia , Criança Hospitalizada , Pré-Escolar , Congo/epidemiologia , Diarreia/epidemiologia , Diarreia/virologia , Feminino , Gastroenterite/virologia , Genótipo , Humanos , Lactente , Masculino , Norovirus/genética , Prevalência , Fatores de Risco
11.
Emerg Infect Dis ; 25(8): 1612-1614, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31310212

RESUMO

During June 2017-December 2018, norovirus was responsible for 10.9% of acute gastroenteritis cases in Thailand. Genogroup I (GI) was found in 14% of samples, of which 12 were co-infected with genogroup II (GII). In 35.8% of samples, GII.Pe-GII.4 Sydney predominated. Diverse recombinant strains of GI and GII norovirus co-circulated year-round.


Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Genótipo , Norovirus/genética , Recombinação Genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecções por Caliciviridae/história , Criança , Pré-Escolar , Fezes/virologia , Gastroenterite/história , Variação Genética , História do Século XXI , Humanos , Lactente , Pessoa de Meia-Idade , Norovirus/classificação , Filogenia , RNA Viral , Tailândia/epidemiologia , Carga Viral , Adulto Jovem
12.
Emerg Infect Dis ; 25(8): 1556-1559, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31310222

RESUMO

We identified a novel recombinant GII.P16-GII.12 norovirus associated with epidemic and endemic gastroenteritis during March 1, 2018-February 12, 2019, in Alberta, Canada. GII.12 viruses have not been detected in Alberta since 2000. Comparing the full genome of this strain to previously published sequences revealed this virus to be a novel recombinant strain.


Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Doenças Transmissíveis Emergentes/epidemiologia , Doenças Transmissíveis Emergentes/virologia , Gastroenterite/epidemiologia , Gastroenterite/virologia , Norovirus/genética , Recombinação Genética , Alberta/epidemiologia , Evolução Molecular , Genótipo , Humanos , Mutação , Norovirus/classificação , Fases de Leitura Aberta , Filogenia , RNA Viral
13.
BMC Infect Dis ; 19(1): 592, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31286917

RESUMO

BACKGROUND: Norovirus (NoV) is recognized as a leading cause of acute gastroenteritis (AGE) outbreaks in settings globally. Studies have shown that employees played an important role in the transmission mode during some NoV outbreaks. This study aimed to investigate the prevalence of NoV infection and duration of NoV shedding among employees during NoV outbreaks, as well as factors affecting shedding duration. METHODS: Specimens and epidemiological data were collected from employees who were suspected of being involved in the transmission or with AGE symptoms during NoV outbreaks in Xuhui District, Shanghai, from 2015 to 2017. Specimens were detected using real-time RT-PCR to determine whether or not employees had become infected with NoV. Specimens were collected every 3-7 days from NoV-infected employees until specimens became negative for NoV. RESULTS: A total of 421 employees were sampled from 49 NoV outbreaks, and nearly 90% of them (377/421) were asymptomatic. Symptomatic employees showed significantly higher prevalence of NoV infection than asymptomatic ones (70.5% vs. 17.0%, P < 0.01). The average duration of NoV shedding was 6.9 days (95% confidence interval: 6.1-7.7 days) among 88 NoV-infected individuals, and was significantly longer in symptomatic individuals than in asymptomatic ones (9.8 days vs. 5.6 days, P < 0.01). In Cox proportional-hazards model, after adjusting age and gender, symptoms was the only factor associated with duration of NoV shedding. CONCLUSIONS: Compared with asymptomatic employees, symptomatic employees had higher prevalence of NoV infection and longer durations of NoV shedding. Since NoV shedding duration among NoV-infected employees tends to be longer than their isolation time during outbreaks, reinforcement of hygiene practices among these employees is especially necessary to reduce the risk of virus secondary transmissions after their return to work.


Assuntos
Infecções por Caliciviridae , Surtos de Doenças/estatística & dados numéricos , Gastroenterite , Norovirus/genética , Adulto , Canal Anal/virologia , Infecções Assintomáticas/epidemiologia , Infecções por Caliciviridae/diagnóstico , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , China/epidemiologia , Feminino , Gastroenterite/diagnóstico , Gastroenterite/epidemiologia , Gastroenterite/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , RNA Viral/análise , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real
14.
PLoS Pathog ; 15(7): e1007940, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31329638

RESUMO

Human norovirus (HNoV) is the leading cause of acute gastroenteritis and is spread by fecal shedding that can often persist for weeks to months after the resolution of symptoms. Elimination of persistent viral reservoirs has the potential to prevent outbreaks. Similar to HNoV, murine norovirus (MNV) is spread by persistent shedding in the feces and provides a tractable model to study molecular mechanisms of enteric persistence. Previous studies have identified non-structural protein 1 (NS1) from the persistent MNV strain CR6 as critical for persistent infection in intestinal epithelial cells (IECs), but its mechanism of action remains unclear. We now find that the function of CR6 NS1 is regulated by apoptotic caspase cleavage. Following induction of apoptosis in infected cells, caspases cleave the precursor NS1/2 protein, and this cleavage is prevented by mutation of caspase target motifs. These mutations profoundly compromise CR6 infection of IECs and persistence in the intestine. Conversely, NS1/2 cleavage is not strictly required for acute replication in extra-intestinal tissues or in cultured myeloid cells, suggesting an IEC-centric role. Intriguingly, we find that caspase cleavage of CR6 NS1/2 reciprocally promotes caspase activity, potentiates cell death, and amplifies spread among cultured IEC monolayers. Together, these data indicate that the function of CR6 NS1 is regulated by apoptotic caspases, and suggest that apoptotic cell death enables epithelial spread and persistent shedding.


Assuntos
Mucosa Intestinal/virologia , Norovirus/patogenicidade , Proteínas não Estruturais Virais/metabolismo , Animais , Apoptose , Infecções por Caliciviridae/etiologia , Infecções por Caliciviridae/patologia , Infecções por Caliciviridae/virologia , Caspases/metabolismo , Células Cultivadas , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Células Epiteliais/virologia , Feminino , Gastroenterite/etiologia , Gastroenterite/patologia , Gastroenterite/virologia , Interações entre Hospedeiro e Microrganismos , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Knockout , Modelos Biológicos , Células Mieloides/metabolismo , Células Mieloides/patologia , Células Mieloides/virologia , Norovirus/genética , Norovirus/fisiologia , Proteínas não Estruturais Virais/genética , Replicação Viral , Eliminação de Partículas Virais
15.
Arch Virol ; 164(9): 2327-2332, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31177352

RESUMO

Two distinct genotypes responsible for rabbit hemorrhagic disease (RHD) are reported, GI.1 (RHDV) and GI.2 (RHDV2). Vaccines based on these two genotypes are only partially cross-protective. Hence, knowing which genotype is circulating is important for appropriate control measures. We have investigated 25 field samples isolated between 2015 and 2018 from rabbits with clinical signs of RHD. Only GI.2 (RHDV2) is currently circulating in Tunisia. All Tunisian samples were grouped together with typical genotypic and phenotypic mutations. Therefore, we recommend initiating an extensive preventive vaccination program based on GI.2 vaccines in addition to a regular monitoring of the circulating lagoviruses.


Assuntos
Infecções por Caliciviridae/veterinária , Vírus da Doença Hemorrágica de Coelhos/genética , Vírus da Doença Hemorrágica de Coelhos/isolamento & purificação , Filogenia , Coelhos/virologia , Sequência de Aminoácidos , Animais , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Genótipo , Vírus da Doença Hemorrágica de Coelhos/química , Vírus da Doença Hemorrágica de Coelhos/classificação , Dados de Sequência Molecular , Alinhamento de Sequência , Tunísia/epidemiologia , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/metabolismo
16.
Lett Appl Microbiol ; 69(3): 175-180, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31220345

RESUMO

Although norovirus (NoV) is the major cause of gastroenteritis, with the largest number of NoV food poisoning cases in Japan, limited information is available regarding NoV detection in food. This study aimed to detect NoV in food samples during the 2015-2016 suspected foodborne outbreaks in Tokyo; 352 food samples from 64 NoV food poisoning outbreaks were collected. Bacterial culturing was performed for sample pretreatment and real-time reverse transcription polymerase chain reaction was conducted for NoV screening. The NoV detection rate was 1·7% (6/352). NoV-positive food samples included leftover boxed lunch, mackerel fillet (foodstuff), aburi salmon slice (partially seared salmon slice), raw tuna as a chirashizushi ingredient, raw amberjack as a sushi topping and ice for drinks. Since fresh fish as sushi toppings or ingredients and ice were consumed without heating, they may present a higher risk of viral infection. NoV-positive food samples were obtained from five outbreaks, wherein food handlers were NoV-positive in four. Each partial VP1 sequence from food samples matched completely with those in NoV-positive individuals and food handlers. Hence, food handlers play a potentially important role in food-based NoV transmission in all five outbreaks; therefore, hygiene education among them is essential to prevent NoV foodborne outbreaks. SIGNIFICANCE AND IMPACT OF THE STUDY: Significance and Impact of the Study: Norovirus (NoV) is a leading cause of foodborne outbreak in Japan. The most frequent route of transmission in NoV foodborne outbreaks is secondary contamination via infected food handlers. However, limited information is available regarding NoV contamination in food samples. This study reports the detection of NoV in food samples to elucidate the source and route of NoV infection leading to outbreaks for 2 years in Tokyo. Our data potentially contribute to education and the development of safe food-handling strategies among food handlers and employees in the food industry through elucidation of risk factors associated with NoV contamination.


Assuntos
Infecções por Caliciviridae/transmissão , Doenças Transmitidas por Alimentos/virologia , Gastroenterite/virologia , Norovirus/isolamento & purificação , Alimentos Crus/virologia , Animais , Infecções por Caliciviridae/virologia , Surtos de Doenças , Peixes/virologia , Manipulação de Alimentos , Humanos , Japão , Norovirus/genética , Reação em Cadeia da Polimerase em Tempo Real , Tóquio
17.
Immunity ; 50(6): 1530-1541.e8, 2019 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-31216462

RESUMO

Rapidly evolving RNA viruses, such as the GII.4 strain of human norovirus (HuNoV), and their vaccines elicit complex serological responses associated with previous exposure. Specific correlates of protection, moreover, remain poorly understood. Here, we report the GII.4-serological antibody repertoire-pre- and post-vaccination-and select several antibody clonotypes for epitope and structural analysis. The humoral response was dominated by GII.4-specific antibodies that blocked ancestral strains or by antibodies that bound to divergent genotypes and did not block viral-entry-ligand interactions. However, one antibody, A1431, showed broad blockade toward tested GII.4 strains and neutralized the pandemic GII.P16-GII.4 Sydney strain. Structural mapping revealed conserved epitopes, which were occluded on the virion or partially exposed, allowing for broad blockade with neutralizing activity. Overall, our results provide high-resolution molecular information on humoral immune responses after HuNoV vaccination and demonstrate that infection-derived and vaccine-elicited antibodies can exhibit broad blockade and neutralization against this prevalent human pathogen.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Infecções por Caliciviridae/imunologia , Infecções por Caliciviridae/prevenção & controle , Norovirus/imunologia , Vacinas Virais/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Antivirais/química , Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Linhagem Celular , Sequência Conservada , Epitopos/química , Epitopos/imunologia , Humanos , Imunoglobulina G/imunologia , Modelos Moleculares , Norovirus/classificação , Ligação Proteica , Conformação Proteica , Proteínas Recombinantes/imunologia , Vacinação
18.
Virus Res ; 267: 21-25, 2019 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-31054932

RESUMO

Human noroviruses (HuNoVs) are a leading cause of acute gastroenteritis worldwide. It is unclear which arm of the immune system regulates resistance to HuNoV infection. Thus, we studied the pathogenesis of human norovirus (HuNoV) in T-B-NK+ Severe Combined Immunodeficiency (SCID) gnotobiotic pigs to investigate the role of innate (especially, natural killer (NK) cells) immunity in HuNoV infection. Forty SCID and non-SCID pigs were randomly grouped: 1) SCID+HuNoV (n = 12); 2) non-SCID+HuNoV (n = 14); 3) SCID mock-inoculated (n = 6); and 4) non-SCID mock-inoculated (n = 8). Pigs (8-14-day-old) were inoculated orally with GII.4 HuNoV strain HS292 (mean 9.1 log10 genomic equivalents/pig) or mock. Daily fecal consistency and fecal viral RNA shedding, and histopathology (at euthanasia) were evaluated. Frequencies of blood and ileal T, B, and NK cells were analyzed by flow cytometry, and a NK cell cytotoxicity assay was performed at post-inoculation day (PID) 8. Unlike the increased infectivity of HuNoV observed previously in T-B-NK- SCID pigs (Lei et al., 2016. Sci. Rep. 6, 25,222), there was no significant difference in frequency of pigs with diarrhea and diarrhea days between T-B-NK+ SCID+HuNoV and non-SCID+HuNoV groups. Cumulative fecal HuNoV RNA shedding at PIDs 1-8, PIDs 9-27, and PIDs 1-27 also did not differ statistically. These observations coincided with the presence of NK cells and NK cell cytotoxicity in the ileum and blood of the SCID pigs. Based on our observations, innate immunity, including NK cell activity, may be critical to mediate or reduce HuNoV infection in T-B-NK+ SCID pigs, and potentially in immunocompetent patients.


Assuntos
Infecções por Caliciviridae/imunologia , Imunidade Inata , Células Matadoras Naturais/imunologia , Norovirus/imunologia , Imunodeficiência Combinada Severa/virologia , Animais , Infecções por Caliciviridae/virologia , Diarreia/virologia , Fezes/virologia , Vida Livre de Germes , Humanos , Norovirus/patogenicidade , Suínos , Eliminação de Partículas Virais
19.
Biomed Res Int ; 2019: 5201790, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31080820

RESUMO

Rabbit hemorrhagic disease (RHD) is an acute, high fatal contagious disease induced by rabbit hemorrhagic disease virus (RHDV) with acute severe hepatic injury and causes huge economic loss worldwide. In order to develop an effective and reliable drug to treat this disease in clinic, a prescription formulated with baicalin, linarin, icariin, and notoginsenoside R1 (BLIN) according to the theory of syndrome differentiation and treatment in traditional Chinese veterinary medicine was applied to investigate its curative effects against RHD in vivo. The preliminary study results showed that BLIN prescription exerted good curative effect on RHD therapy. To further validate the curative effect and to investigate the possible related curative mechanisms of this drug, the survival rates, the plasma biochemical indexes of hepatic function, the plasma evaluation indexes of oxidative injury, and the RHDV gene expression levels were detected and then the correlation among these indexes was also analyzed. These results showed that BLIN prescription could significantly increase the survival rate, reduce the hepatic injury severity, alleviate the oxidative injury, and decrease the RHDV gene expression level in rabbits infected with RHDV. All these results indicate that BLIN prescription possesses outstanding curative effect against RHD, and the curative mechanism may be related to its antioxidant and anti-RHDV activities. Therefore, this prescription can be expected to be exploited into a new candidate for RHD therapy in clinic.


Assuntos
Infecções por Caliciviridae/tratamento farmacológico , Flavonoides/farmacologia , Flavonoides/uso terapêutico , Vírus da Doença Hemorrágica de Coelhos/efeitos dos fármacos , Animais , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Infecções por Caliciviridae/sangue , Infecções por Caliciviridae/patologia , Infecções por Caliciviridae/virologia , Relação Dose-Resposta a Droga , Regulação Viral da Expressão Gênica/efeitos dos fármacos , Ginsenosídeos/farmacologia , Ginsenosídeos/uso terapêutico , Glicosídeos/farmacologia , Glicosídeos/uso terapêutico , Vírus da Doença Hemorrágica de Coelhos/genética , Fígado/efeitos dos fármacos , Fígado/lesões , Fígado/patologia , Coelhos , Taxa de Sobrevida
20.
BMC Infect Dis ; 19(1): 400, 2019 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-31072305

RESUMO

BACKGROUND: Older adults are vulnerable to hospitalization or death from norovirus infection, but the actual disease burden remains unknown. Therefore, we conducted a nationwide survey to estimate the number of inpatients with norovirus gastroenteritis and associated deaths among Japanese older adults. METHODS: We performed a nationwide two-step query targeting 4184 hospital departments selected from 17,575 departments using stratified random sampling according to the number of beds. We asked each department to complete a mail-back questionnaire on the annual numbers of inpatients with infectious gastroenteritis and associated deaths between administrative years 2012 and 2014, and the implementation status of norovirus infection testing. In a second query, we investigated the annual number of inpatients with norovirus gastroenteritis and associated deaths in departments that had reported infectious gastroenteritis inpatients in the first query. Clinical information was collected for inpatients with norovirus gastroenteritis in administrative year 2014. RESULTS: Norovirus testing for patients hospitalized for acute gastroenteritis was routinely conducted in 16% of the responding departments. Although half the departments responded that some acute gastroenteritis inpatients received such testing but others did not. In this situation, numbers of inpatients with norovirus gastroenteritis in Japan were estimated as 31,800 (95% CI: 25,700-37,900) in administrative year 2012, 21,600 (95% CI: 17,700-25,500) in administrative year 2013, and 15,700 (95% CI: 12,900-18,500) in administrative year 2014. The estimated number of associated deaths was approximately 600 in each administrative year. Factors associated with death included higher age, living in long-term care facilities, underlying illnesses such as chronic respiratory diseases, and complications such as aspiration pneumonia. CONCLUSIONS: The actual number of norovirus inpatient would be higher than the estimated here due to the low rate of routinely implemented norovirus testing. Considering Japan's rapidly aging society and the disease burden of norovirus infection among Japanese older adults, it is important to protect this high-risk population from norovirus infection.


Assuntos
Infecções por Caliciviridae/diagnóstico , Gastroenterite/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Infecções por Caliciviridae/complicações , Infecções por Caliciviridae/virologia , Feminino , Gastroenterite/epidemiologia , Gastroenterite/mortalidade , Hospitalização/estatística & dados numéricos , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Norovirus/isolamento & purificação , Fatores de Risco , Análise de Sobrevida
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