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Rotaviruses cause severe gastroenteritis in infants, in which the viruses interact with human histo-blood group antigens (HBGAs) as attachment and host susceptibility factors. While gastroenteritis outbreaks caused by rotaviruses are uncommon in adolescents, we reported here one that occurred in a middle school in China. Rectal swabs and saliva samples were collected from symptomatic and asymptomatic students, and samples were also collected from the environment. Using PCR, followed by DNA sequencing, a single G9P[8] rotavirus strain was identified as the causative agent. The attack rate of the outbreak was 13.5% for boarders, which was significantly higher than that of day students (1.8%). Person-to-person transmission was the most plausible transmission mode. The HBGA phenotypes of the individuals in the study were determined by enzyme immunoassay, using saliva samples, while recombinant VP8* protein of the causative rotavirus strain was produced for HBGA binding assays to evaluate the host susceptibility. Our data showed that secretor individuals had a significantly higher risk of infection than nonsecretors. Accordingly, the VP8* protein bound nearly all secretor saliva samples, but not those of nonsecretors, explaining the observed infection of secretor individuals only. This is the first single-outbreak-based investigation showing that P[8] rotavirus infected only secretors. Our investigation also suggests that health education of school students is an important countermeasure against an outbreak of communicable disease.
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Antígenos de Grupos Sanguíneos/análisis , Brotes de Enfermedades/prevención & control , Gastroenteritis/epidemiología , Infecciones por Rotavirus/epidemiología , Rotavirus/genética , Adolescente , China/epidemiología , Heces/virología , Femenino , Gastroenteritis/virología , Genotipo , Educación en Salud , Humanos , Masculino , Fenotipo , Rotavirus/aislamiento & purificación , Infecciones por Rotavirus/transmisión , Saliva/virología , Análisis de Secuencia de ADNRESUMEN
A novel GII.17 norovirus variant caused major gastroenteritis epidemics in China in 2014 to 2016. To explore the host immune factors in selection of the emergence of this new variant, we characterized its antigenic relatedness with the GII.4 noroviruses that have dominated in China for decades. Through an enzyme-linked immunosorbent assay (ELISA) and a histo-blood group antigen (HBGA) blocking assay using sera from GII.4 and the GII.17 variant-infected patients, respectively, we observed limited cross-immune reactivity by the ELISA but little reactivity by the HBGA blocking assay between GII.4 norovirus and the new GII.17 variant. Our data suggest that, among other possible factors, GII.4-specific herd immunity had little role in the emergence of the new GII.17 variant. Thus, GII.17 may be an important active antigenic type or immunotype that needs to be considered for future vaccine strategies against human noroviruses.
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Anticuerpos Antivirales/sangre , Infecciones por Caliciviridae/virología , Genotipo , Norovirus/clasificación , Norovirus/inmunología , Serogrupo , Adulto , Infecciones por Caliciviridae/epidemiología , Infecciones por Caliciviridae/inmunología , China/epidemiología , Reacciones Cruzadas , Brotes de Enfermedades , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Norovirus/genética , Adulto JovenRESUMEN
Introduction: Norovirus (NoV) is one of the most important agents responsible for viral acute gastroenteritis, among which GII.4 NoV is the predominant strain worldwide, and GII.17 NoV surpassed GII.4 in some epidemic seasons. Rapid and accurate gene recognition is essential for a timely response to NoV outbreaks. Methods: In the present study, the highly conserved regions of GII.4 and GII.17 NoVs were identified in the junction of open reading frame (ORF) 1 and ORF2 and then amplified by isothermal recombinase-aided amplification (RAA), followed by the cleavage of CRISPR-Cas13a with screened CRISPR RNAs (crRNAs) and RAA primers. The entire detection procedure could be completed within 40 min using a thermostat, and the results could be read out by the naked eye under a portable blue light transilluminator. Discussion: The assay showed a high sensitivity of 97.96% and a high specificity of 100.0%. It offered a low limit of detection (LOD) of 2.5×100 copies/reaction and a coincidence rate of 96.75% in 71 clinical fecal samples. Overall, rapid and inexpensive detection of GII.4/GII.17 NoVs was established, which makes it possible to be used in areas with limited resources, particularly in low-income countries. Furthermore, it will contribute to assessing transmission risks and implementing control measures for GII.4/GII.17 NoVs, making healthcare more accessible worldwide.
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Noroviruses (NoVs) are the leading viral pathogens globally causing acute gastroenteritis (AGE) in humans, posing a significant global health threat and economic burden. Recent investigations revealed that human NoVs had been detected in different animals, which raises concerns about whether NoVs are potential zoonotic diseases. This study developed a novel luciferase immunosorbent assay (LISA) to detect GII.6 NoV IgG based on P protein of VP1. The LISA showed high specificity (99.20%) and sensitivity (92.00%) with 4-16 times more sensitivity compared with an ELISA. NoV-LISA was reproducible with human serum regarding the inter- and intra-assay coefficient of variance values. Potential cross-reactivity was also evaluated using mice serum immunized by other antigens, which showed that NoV-LISA could differentiate GII.6 NoV from rotavirus and various genotypes of NoV. Specific GII.6 NoV IgG was widely detected in different domestic and wild animals, including dogs, pigs, bats, rats, and home shrews, with various IgG-positive rates ranging from 2.5 to 74.4%. In conclusion, our newly developed NoV-LISA assay is suitable for NoV-specific IgG detection in humans and animals. The wide distribution of IgG antibodies against human NoV indicates potential zoonotic transmission between humans and animals.
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Introduction: Herd immunity against norovirus (NoV) is poorly understood in terms of its serological properties and vaccine designs. The precise neutralizing serological features of genotype I (GI) NoV have not been studied. Methods: To expand insights on vaccine design and herd immunity of NoVs, seroprevalence and seroincidence of NoV genotypes GI.2, GI.3, and GI.9 were determined using blockade antibodies based on a 5-year longitudinal serosurveillance among 449 residents in Jidong community. Results: Correlation between human histo-blood group antigens (HBGAs) and GI NoV, and dynamic and persistency of antibodies were also analyzed. Seroprevalence of GI.2, GI.3, and GI.9 NoV were 15.1%-18.0%, 35.0%-38.8%, and 17.6%-22.0%; seroincidences were 10.0, 21.0, and 11.0 per 100.0 person-year from 2014 to 2018, respectively. Blockade antibodies positive to GI.2 and GI.3 NoV were significantly associated with HBGA phenotypes, including blood types A, B (excluding GI.3), and O+; Lewis phenotypes Leb+/Ley+ and Lea+b+/Lex+y+; and secretors. The overall decay rate of anti-GI.2 antibody was -5.9%/year (95% CI: -7.1% to -4.8%/year), which was significantly faster than that of GI.3 [-3.6%/year (95% CI: -4.6% to -2.6%/year)] and GI.9 strains [-4.0%/year (95% CI: -4.7% to -3.3%/year)]. The duration of anti-GI.2, GI.3, and GI.9 NoV antibodies estimated by generalized linear model (GLM) was approximately 2.3, 4.2, and 4.8 years, respectively. Discussion: In conclusion, enhanced community surveillance of GI NoV is needed, and even one-shot vaccine may provide coast-efficient health benefits against GI NoV infection.
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Norovirus , Vacunas , Humanos , Estudios Prospectivos , Estudios Seroepidemiológicos , Genotipo , Anticuerpos , Norovirus/genéticaRESUMEN
Noroviruses (NoVs) are the leading cause of viral acute gastroenteritis affecting people of all ages worldwide. The disease is difficult to control due to its widespread nature and lack of an antiviral or vaccine. NoV infection relies on the interaction of the viruses with histo-blood group antigens (HBGAs) as host receptors. Here we investigated inhibition effects of Chinese medicinal herbs against NoVs binding to HBGAs for potential antivirals against NoVs. Blocking assays was performed using the NoV protrusion (P) protein as NoV surrogate and saliva as HBGAs. Among 50 clinically effective Chinese medicinal herbs against gastroenteritis diseases, two herbs were found highly effective. Chinese Gall blocked NoV P dimer binding to type A saliva at IC(50)=5.35 µg/ml and to B saliva at IC(50)=21.7 µg/ml. Similarly, Pomegranate blocked binding of NoV P dimer to type A saliva at IC(50)=15.59 µg/ml and B saliva at IC(50)=66.67 µg/ml. Literature data on preliminary biochemistry analysis showed that tannic acid is a common composition in the extracts of the two herbs, so we speculate that it might be the effective compound and further studies using commercially available, highly purified tannic acid confirmed the tannic acid as a strong inhibitor in the binding of NoV P protein to both A and B saliva (IC(50)≈0.1 µM). In addition, we tested different forms of hydrolysable tannins with different alkyl esters, including gallic acid, ethyl gallate, lauryl gallate, octyl gallate and propyl gallate. However, none of these tannins-derivatives revealed detectable inhibiting activities. Our data suggested that tannic acid is a promising candidate antiviral against NoVs.
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Norovirus/efectos de los fármacos , Plantas Medicinales/química , Receptores Virales/antagonistas & inhibidores , Taninos/farmacología , Antivirales/química , Antivirales/farmacología , Antígenos de Grupos Sanguíneos/metabolismo , Línea Celular Tumoral , Células HeLa , Humanos , Concentración 50 Inhibidora , Modelos Moleculares , Estructura Molecular , Norovirus/metabolismo , Unión Proteica/efectos de los fármacos , Taninos/químicaRESUMEN
High under-five mortality rate remains one of the public health challenges, especially in Sub-Saharan Africa, accounting for more than half of all global cases. Sierra Leone was and is still one of the countries with the highest under-five mortality rate. Using the latest 2019 Sierra Leone Demographic and Health Survey data, we investigated factors associated with under-five mortality in Sierra Leone. A total of 9771 mothers aged 15-49 years in the country were interviewed and included in the analysis. The dependent variable is child status (dead = 1; alive = 0). A total of 871 (9%) children died before their fifth birthday. The maternal age of 20-24 years [adjusted odds ratios (AOR) = 0.46; 95% confidence interval (CI) = 0.33-0.64; P < 0.001] up to 40-44 years (AOR = 0.43; CI = 0.27-0.7; P = 0.001), currently breastfeeding (AOR = 0.20; CI = 0.17-0.24; P < 0.001), maternal media exposure and usage of reading newspapers/magazines less than once a week (AOR = 0.48; CI = 0.28-0.85; P = 0.011) were more likely to enhance child survivability through their fifth birthday. Also, the child sex being female (AOR = 0.68; CI = 0.59-0.79) was more likely to survive under-five mortality compared to their male counterpart. On the other hand, mothers who listened to radio at least once a week (AOR = 1.31; CI = 1.08-1.59; P = 0.007) watched television less than once a week (AOR = 1.48; CI = 1.16-1.90), had two (AOR = 3.4, CI = 2.78-4.16; P < 0.001) or three and above birth (AOR = 8.11; CI = 6.07-10.83; P < 0.001) in five years, had multiple birth children (AOR = 1.41; CI = 1.08-1.86) and very small-sized child at birth (AOR= 1.95; CI = 1.41-2.70) were more likely to lose their children below the age of 5 years. The factors contributing to under-five mortality in Sierra Leone are critical to ensuring child survival and improving maternal health. Breastfeeding, maternal age, media exposure, child's sex, multiple birth type, very small-sized child and the total number of births in 5 years were significant drivers of under-five mortality. The result affirms the need for attention to be focused on enhancing the survival rate of under-five children in Sierra Leone.
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Lactancia Materna , Madres , Niño , Recién Nacido , Femenino , Masculino , Humanos , Preescolar , Sierra Leona/epidemiología , África del Sur del Sahara , DemografíaRESUMEN
Human noroviruses (NoVs) are an important cause of epidemic acute gastroenteritis. Their role in sporadic cases, however, is less clear. In this study, we performed a two-year surveillance (September 2005 to August 2007) of NoV gastroenteritis in outpatient clinics in a southern city of China, Jiangmen City. NoVs were detected in 115 patients (115/881, 13.1%) with 30 (26.1%) co-infections with rotaviruses. Sequence analysis showed that all 115 NoVs belonged to genogroup II, with GII.4 being the most predominant (87.8%). NoV-associated infection can be seen year-around, with autumn and winter peaks. This study provides basic information on sporadic cases of major NoV gastroenteritis in children in different seasons, which is valuable for future disease control and prevention.
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Infecciones por Caliciviridae/virología , Gastroenteritis/virología , Norovirus/genética , Infecciones por Caliciviridae/epidemiología , Preescolar , China/epidemiología , Heces/virología , Gastroenteritis/epidemiología , Humanos , Lactante , Recién Nacido , Epidemiología Molecular , Filogenia , Estaciones del Año , Factores de TiempoRESUMEN
An HPLC-MS/MS method has been developed and validated for the determination of venlafaxine enantiomers in human plasma and applied to a pharmacokinetic study in healthy Chinese volunteers. The method was carried out on a vancomycin chiral column (5 µm, 250 × 4.6 mm) maintained at 25°C. The mobile phase was methanol-water containing 30 mmol/L ammonium acetate, pH 3.3 adjusted with aqueous ammonia (8:92, v/v) at the flow rate 1.0 mL/min. A tandem mass spectrometer with an electrospray interface was operated in the multiple reaction monitoring mode to detect the selected ions pair at m/z 278.0 â 120.8 for venlafaxine enantiomers and m/z 294.8 â 266.7 for estazolanm (internal standard). The method was linear in the concentration range of 0.28-423.0 ng/mL. The lower limit of quantification was 0.28 ng/mL. The intra-and inter-day relative standard deviations were less than 9.7%. The method was successfully applied for the evaluation of pharmacokinetic profiles of venlafaxine enantiomers in 18 healthy volunteers. Validation parameters such as the specificity, linearity, precision, accuracy and stability were evaluated, giving results within the acceptable range. Pharmacokinetic parameters of the venlafaxine enantiomers were measured in the 18 healthy Chinese volunteers who received a single regimen with venlafaxine hydrochloride capsules. The results show that AUC((0-∞)) , C(max) and t(1/2) between S-venlafaxine and R-venlafaxine are significantly different (p < 0.05).
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Antidepresivos de Segunda Generación/análisis , Antidepresivos de Segunda Generación/farmacocinética , Cromatografía Líquida de Alta Presión/métodos , Ciclohexanoles/análisis , Ciclohexanoles/farmacocinética , Espectrometría de Masas en Tándem/métodos , Adulto , Antidepresivos de Segunda Generación/sangre , Antidepresivos de Segunda Generación/química , Área Bajo la Curva , China , Ciclohexanoles/sangre , Ciclohexanoles/química , Estabilidad de Medicamentos , Humanos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Estereoisomerismo , Vancomicina/química , Clorhidrato de Venlafaxina , Adulto JovenRESUMEN
INTRODUCTION: Noroviruses are the leading cause of viral acute gastroenteritis affecting all age groups. Since 2014, the previous rarely reported GII.P17-GII.17 and recombinant GII.P16-GII.2 norovirus emerged, replacing GII.4 predominant genotype, causing increased outbreaks in China and other countries. Meanwhile, GII.4/2012 Sydney strain has re-emerged as the dominant variant in many places in 2015-2018. The role of herd immunity as the driving force during these new emerging or re-emerging noroviruses is poorly defined. Serological surveillance studies on community-based prospective cohort on norovirus are highly needed. METHODS AND ANALYSES: This study will include 1000 out of 9798 participants aged 18 years and above from Caofeidian district, Tangshan city, northern China. Baseline data on sociodemographic characteristics and blood samples were collected in 2013-2014. Blood collection will be replicated annually throughout the cohort until 2023. Saliva samples were also collected in 2016. The seroprevalence and seroincidence of blockade antibodies against norovirus genotypes of GII.P17-GII.17, GII.P16-GII.2, the re-emerged GII.4/2012 and potential novel pandemic variants will be evaluated by ELISA. Associations between genotype blockade antibodies and sociodemographic factors and human histo-blood group antigens will be evaluated using univariate and multivariate analysis. The dynamics of herd immunity duration will be estimated in this longitudinal surveillance. ETHICS AND DISSEMINATION: The study has been approved by the Ethical Committees of the Staff Hospital of Jidong oil-field of China National Petroleum Corporation. This study will provide insight into the seroprevalence and seroincidence of noroviruses, and their relationships with sociodemographic characteristics and genetic susceptibility. It will also explain herd immunity of the emerged and re-emerged genotypes or variants. The study will further enable an understanding of the mechanism driving the replacement of norovirus genotypes. Research findings will be disseminated in peer-reviewed journals and at scientific meetings.
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Infecciones por Caliciviridae , Norovirus , Adolescente , Adulto , Infecciones por Caliciviridae/epidemiología , China/epidemiología , Brotes de Enfermedades , Genotipo , Humanos , Epidemiología Molecular , Norovirus/genética , Filogenia , Estudios Prospectivos , Estudios Seroepidemiológicos , Adulto JovenRESUMEN
Human astroviruses (HAstVs) are one of the major viral agents of acute gastroenteritis (AGE) in all age groups, especially in young children. In this study, new one-step real-time RT-PCR and nested RT-PCR assays were developed to detect HAstVs. HAstVs were identified in 46 (8.75%) of 526 stool samples in Jiangmen City over 1 year, including 43 (9.15%) of 470 children and 3 (5.4%) of 56 adults, and HAstV-1 was the most predominant strain. This finding suggests that HAstVs infections are common in Jiangmen City, China. Further detailed molecular epidemiological studies are required for understanding the prevalence of HAstVs infection and gaining knowledge about the circulating genotypes.
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Infecciones por Astroviridae/epidemiología , Gastroenteritis/epidemiología , Mamastrovirus/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Adulto , Infecciones por Astroviridae/virología , Niño , China/epidemiología , Heces/virología , Gastroenteritis/virología , Humanos , Mamastrovirus/genética , Filogenia , Prevalencia , Análisis de Secuencia de ADNRESUMEN
AIM: Noroviruses (NoVs) are an important cause of acute gastroenteritis but knowledge on the disease burden and epidemiology in children in the developing countries remains limited. In this study, we performed a surveillance of NoV gastroenteritis in children of China to address some of the questions. METHODS: Faecal specimens from children (<5 years of age) at outpatient clinics of the Nan Fang Hospital in Guangzhou, China during the fall-winter seasons in 2003-2006 were tested for rotaviruses (RVs) and NoVs. A questionnaire on clinical records and hygiene habits was collected from each patient. RESULTS: Among 957 stool specimens tested, 488 (51%) specimens were positive for RVs. NoVs were detected in 112 (24%) of the 469 RV negative specimens. The Genogroup II (GII), particularly GII-4, viruses were predominant. No significant difference of clinical symptoms, hospitalisation and patient care expenses were found between children infected with NoVs and RVs. Consumption of uncooked food is a risk for NoV infection. Contact with diarrhoea patients is a suspected risk factor. Cutting nails frequently is a protective factor against NoV infection. CONCLUSIONS: NoVs are an important cause of acute gastroenteritis in children which need special attention of patient care at the clinics in addition to RVs. The awareness of those risk factors may help future disease control and prevention.
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Gastroenteritis/epidemiología , Gastroenteritis/etiología , Norovirus/aislamiento & purificación , Estaciones del Año , Población Urbana , Preescolar , China/epidemiología , Gastroenteritis/virología , Humanos , Higiene , Norovirus/patogenicidad , Vigilancia de la Población , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Riesgo , Encuestas y CuestionariosRESUMEN
Characterizing diversity and the antigenic relatedness of norovirus remains a primary focus in understanding its biological properties and vaccine designs. The precise antigenic and serological features of GI genotypes have not been studied. The study represented an investigation on a gastroenteritis outbreak related to GI.3 norovirus and the three most detected GI genotypes, GI.2 (belonging to immunotype B), GI.3 and GI.9 (belonging to immunotype C), were selected to characterize their phylogenetic relationship, HBGA binding profiles and antigenic relatedness within (intra-immunotype), and between (inter-immunotypes) genotypes using mouse sera and patient's serum samples from the GI.3 related outbreak. Wide HBGA binding profiles and evolution of binding affinity were observed in the three GI genotypes studied. A low specific blockade antibody to GI.3 in the population generated the pool of susceptible individuals and supported virus spread in the outbreak. We found strong blockade immune response in homologous strains, moderate intra-immunotype blockade but weak inter-immunotypes blockade in humans following GI.3 norovirus infections. These findings further support the immunotypes grouping and will be valuable for optimizing the design of norovirus vaccine.
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OBJECTIVE: The Jidong Women Health Cohort Study is a prospective cohort study on female-specific characteristics and risks of chronic diseases in Chinese women and focuses on the potential association between menopause and risks of cardiovascular disease (CVD). METHODS: The study includes 4,179 female participants with an age of older than 18 years from Caofeidian district, Tangshan city, northern China. Baseline information on female-specific characteristics and potential cardiovascular risk factors was collected and all the participants underwent a physical examination with blood samples collected in 2013. To establish a better risk assessment tool of female CVD, updated information from questionnaire investigation, physical examinations and occurrence of outcome events will be collected through a longitudinal follow-up annually up to the year 2024. RESULTS: At baseline, Mean age of the participants was 42.3 ± 12.8 years. Reproduction occurred in 2,948 participants (70.5%), menopausal transition in 173 (4.3%), and postmenopause in 1,058 (25.3%). The incidence of arterial hypertension, dyslipidemia, and diabetes showed significant difference across different groups stratified by Stage of Reproductive Aging Workshop (STRAW) system (P < 0.05). CONCLUSION: The Jidong Women Health Cohort Study will contribute to the scientific evidence on association between female-specific characteristics and cardiovascular risks, and will also be helpful to provide a new path for early detection and prevention of CVD.
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Enfermedades Cardiovasculares/epidemiología , Adulto , China/epidemiología , Estudios de Cohortes , Femenino , Humanos , Menopausia , Persona de Mediana Edad , Proyectos de Investigación , Factores de Riesgo , Salud de la MujerRESUMEN
Rotaviruses are known to recognize human histo-blood group antigens (HBGAs) as a host ligand that is believed to play an important role in rotavirus host susceptibility and host range. In this study, paired fecal and saliva samples collected from children with viral gastroenteritis, as well as paired serum and saliva samples collected from the general population in south China were studied to evaluate potential association between rotavirus infections and human HBGA phenotypes. Rotavirus was detected in 75 (28%) of 266 fecal samples and P[8] rotaviruses were found to be the predominant genotype. The HBGA phenotypes of the rotavirus-infected children were determined through their saliva samples. Secretor statuses were found to correlate with the risk of rotavirus infection and all P[8]/P[4] rotavirus infected children were secretors. Accordingly, recombinant VP8* proteins of the P[8]/P[4] rotaviruses bound saliva samples from secretor individuals. Furthermore, correlation between serum P[8]/P[4]-specific IgG and host Lewis and secretor phenotypes has been found among 206 studied serum samples. Our study supported the association between rotavirus infection and the host HBGA phenotypes, which would help further understanding of rotavirus host range and epidemiology.
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Heces/virología , Genotipo , Infecciones por Rotavirus/genética , Infecciones por Rotavirus/metabolismo , Rotavirus/genética , Rotavirus/metabolismo , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Infecciones por Rotavirus/patologíaRESUMEN
The GII.4 noroviruses (NoVs) are a single genotype that is responsible for over 50% of NoV gastroenteritis epidemics worldwide. However, GII.4 NoVs have been found to undergo antigenic drifts, likely selected by host herd immunity, which raises an issue for vaccine strategies against NoVs. We previously characterized GII.4 NoV antigenic variations and found significant levels of antigenic relatedness among different GII.4 variants. Further characterization of the genetic and antigenic relatedness of recent GII.4 variants (2008b and 2010 cluster) was performed in this study. The amino acid sequences of the receptor binding interfaces were highly conserved among all GII.4 variants from the past two decades. Using serum samples from patients enrolled in a GII.4 virus challenge study, significant cross-reactivity between major GII.4 variants from 1998 to 2012 was observed using enzyme-linked immunosorbent assays and HBGA receptor blocking assays. The overall abilities of GII.4 NoVs to bind to the A/B/H HBGAs were maintained while their binding affinities to individual ABH antigens varied. These results highlight the importance of human HBGAs in NoV evolution and how conserved antigenic types impact vaccine development against GII.4 variants.
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Antígenos Virales/metabolismo , Antígenos de Grupos Sanguíneos/metabolismo , Infecciones por Caliciviridae/inmunología , Gastroenteritis/inmunología , Sueros Inmunes/metabolismo , Norovirus/inmunología , Secuencia de Aminoácidos , Animales , Antígenos Virales/química , Antígenos Virales/genética , Antígenos de Grupos Sanguíneos/química , Infecciones por Caliciviridae/sangre , Infecciones por Caliciviridae/virología , Secuencia Conservada , Evolución Molecular , Gastroenteritis/sangre , Gastroenteritis/virología , Variación Genética , Humanos , Ratones , Norovirus/clasificación , Norovirus/genéticaRESUMEN
During the past norovirus (NoV) epidemic season, a new GII.17 variant emerged as a predominant NoV strain, surpassed the GII.4 NoVs, causing outbreaks of acute gastroenteritis (AGE) in China. Here we report a study of an AGE outbreak in an elementary school in December 2014 caused by the new GII.17 NoV to explore the potential mechanism behind the sudden epidemics of the GII.17 NoV. A total of 276 individuals were sick with typical NoV infection symptoms of vomiting (93.4%), abdominal pain (90.4%), nausea (60.0%), and diarrhea (10.4%) at an attack rate of 5.7-16.9%. Genotyping of the symptomatic patients showed that individuals with a secretor positive status, including those with A, B, and O secretors and Lewis positive blood types, were sensitive to the virus, while the non-secretors and the Lewis negative individual were not. Accordingly, the recombinant capsid P protein of the GII.17 isolate showed a wide binding spectrum to saliva samples of all A, B, and O secretors. Thus, the broad binding spectrum of the new GII.17 variant could explain its widely spread nature in China and surrounding areas in the past two years.
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Antígenos Virales/metabolismo , Infecciones por Caliciviridae/virología , Brotes de Enfermedades , Gastroenteritis/epidemiología , Gastroenteritis/virología , Norovirus/fisiología , Sistema del Grupo Sanguíneo ABO/metabolismo , Secuencia de Aminoácidos , Sitios de Unión , China/epidemiología , Susceptibilidad a Enfermedades , Heces/virología , Humanos , Antígenos del Grupo Sanguíneo de Lewis/metabolismo , Datos de Secuencia Molecular , Mutación/genética , Fenotipo , Estructura Terciaria de Proteína , Factores de Riesgo , Saliva/virología , Homología Estructural de Proteína , EstudiantesRESUMEN
AIM: During emergency period, infectious diseases can be a major threat to military forces. During field training in southern China, diarrhea is the main cause of nonbattle injury. To evaluate the causes of and risk factors for diarrhea in emergency period, we collected clinical and epidemiological data from the People's Liberation Army (PLA) during field training in southern China. METHODS: From September 25 to October 2 1997, 2636 military personnel were investigated. Fecal sample cultures for lapactic pathogens were obtained from 103 military personnel with diarrhea. In addition, a questionnaire was administered to 103 cases and 206 controls to evaluate the association between illness and potential risk factors. At the same time, another questionnaire of 1:4 case-case control was administered to 22 severe cases (each severe case paired 4 mild cases). RESULTS: The training troop's diarrhea incidence rate was significantly higher than that of garrison. The diarrhea incidence rate of officers was significantly lower than that of soldiers. A lapactic pathogen was identified in 63.1% (65/103) of the troops with diarrhea. Enterotoxigenic Escherichia coli (35.0%) and plesiomona shigelloides (16.5%) were the most common bacterial pathogens. All bacterial isolates were sensitive to norfloxacin and ceftazidine. However, almost all of them were resistant to sulfamethoxazole, trimethoprim-sulfamethoxazole, oxytetracycline, doxycycline, furazolidone, ampicillin and cloromycetin to a different degree. Risk factors associated with diarrhea included drinking raw water, eating outside, contacting diarrhea patients, lacking sanitation, depression, lacking sleep, which were established by multiple-factor logistic regression analysis. In addition, the unit incidence rate was associated with the density of flies and the average daily boiled water available by regression and discriminate analysis. CONCLUSION: A series of risk factors are associated with the incidence rate of diarrhea. Our results may provide a useful basis for prevention and cure of diarrhea in emergency period of PLA.
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Diarrea/epidemiología , Personal Militar , Enfermedad Aguda , Adolescente , Adulto , Estudios de Casos y Controles , China , Diarrea/microbiología , Infecciones por Escherichia coli/epidemiología , Infecciones por Bacterias Gramnegativas/epidemiología , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Plesiomonas , Factores de Riesgo , Saneamiento , Abastecimiento de Agua , Tiempo (Meteorología)RESUMEN
OBJECTIVE: To investigate of human calicivirus (HuCV) infection in the children of Guangzhou, the capital of Guangdong Province at China, and conduct preliminary study of the prevalence of the virus. METHODS: Serum specimens from 266 children of different ages were tested by an indirect enzyme-linked immunosorbent assay (ELISA) for specific IgG against recombinant Norwalk virus particles (rNV), recombinant Mexico virus partides(rMX) and recombinat 387 Virus particles(r387), respectively, and fecal specimens were collected for detection of HuCV RNA using reverse transcriptional (RT)-PCR assisted by sequence analysis on the basis of comparison of the amplified product with the sequence entries in GenBank. RESULTS: The seroprevalence was 68.0% for rNV, 51.5% for rMX and 71.1% for r387 in the cohort of children enrolled in this study. Norwalk-like viruses (NLVs) were detected in 4 out of the 100 fecal specimens collected from cases of nonbacterial gastroenteritis during the peak season of diarrhea, and also in 3 of the 10 fecal specimens collected during the outbreak of diarrhea in an elementary school. CONCLUSIONS: Sporadic and fulminant NLV infections are present in Guangzhou. The children have the infection in their infancy, and the infection rate increases sharply with age.
Asunto(s)
Infecciones por Caliciviridae/epidemiología , Gastroenteritis/epidemiología , Virus Norwalk , Anticuerpos Antivirales/sangre , China/epidemiología , Humanos , Inmunoglobulina G/sangre , Virus Norwalk/inmunologíaRESUMEN
OBJECTIVE: To clone and construct expression vector pET32a+-tlh to acquire biologically functional thermolabile hemolysin of Vibrio parahaemolyticus. METHODS: tlh gene was cloned and the expression vector pET32a+-tlh constructed. The tlh gene of Vibrio parahaemolyticus was expressed in DE3 in the form of inclusion body, which was resolved in 8 mol/L urea followed by purification of the fusion protein using affinity chromatography and renaturation through gradient dialysis, protein concentration reduction and oxidoreduction. RESULTS AND CONCLUSION: The purified and renatured protein possessed hemolytic and immunogenic activities.