RESUMEN
Five new seco-labdane-type diterpenoids, caesalatisics A-E (1-5), were isolated from the leaves of Caesalpinia latisiliqua (Cav.) Hattink. Their chemical structures were determined using 1D and 2D NMR, mass spectra, and circular dichroism spectroscopies.
Asunto(s)
Caesalpinia , Diterpenos , Caesalpinia/química , Diterpenos/análisis , Espectroscopía de Resonancia Magnética , Estructura Molecular , Hojas de la Planta/químicaRESUMEN
We performed a case-control investigation to identify risk factors for norovirus infections among children in Vietnam. Of samples from 1,419 children who had diarrhea and 609 who were asymptomatic, 20.6% and 2.8%, respectively, were norovirus positive. Risk factors included residential crowding and symptomatic contacts, indicating person-to-person transmission of norovirus.
Asunto(s)
Infecciones por Caliciviridae/epidemiología , Diarrea/epidemiología , Gastroenteritis/epidemiología , Norovirus , Infecciones por Caliciviridae/historia , Infecciones por Caliciviridae/transmisión , Estudios de Casos y Controles , Niño , Diarrea/historia , Diarrea/virología , Gastroenteritis/historia , Gastroenteritis/virología , Historia del Siglo XXI , Humanos , Norovirus/clasificación , Norovirus/genética , Norovirus/aislamiento & purificación , Prevalencia , Estudios Prospectivos , Factores de Riesgo , Estaciones del Año , Vietnam/epidemiologíaRESUMEN
Rotavirus (RoV) and Norovirus (NoV) are the main causes of viral gastroenteritis. Currently, there is no validated multiplex real-time PCR that can detect and quantify RoV and NoV simultaneously. The aim of the study was to develop, validate, and internally control a multiplex one-step RT real-time PCR to detect and quantify RoV and NoV in stool samples. PCR sensitivity was assessed by comparing amplification against the current gold standard, enzyme immunoassay (EIA), on stool samples from 94 individuals with diarrhea and 94 individuals without diarrhea. PCR detected 10% more RoV positive samples than EIA in stools samples from patients with diarrhea. PCR detected 23% more NoV genogroup II positive samples from individuals with diarrhea and 9% more from individuals without diarrhea than EIA, respectively. Genotyping of the PCR positive/EIA negative samples suggested the higher rate of PCR positivity, in comparison to EIA, was due to increased sensitivity, rather than nonspecific hybridization. Quantitation demonstrated that the viral loads of RoV and NoV in the stools of diarrheal patients were an order of magnitude greater than in individuals without diarrhea. This internally controlled real-time PCR method is robust, exhibits a high degree of reproducibility, and may have a greater utility and sensitivity than commercial EIA kits.
Asunto(s)
Infecciones por Caliciviridae/diagnóstico , Reacción en Cadena de la Polimerasa Multiplex , Norovirus/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa , Infecciones por Rotavirus/diagnóstico , Rotavirus/aislamiento & purificación , Infecciones por Caliciviridae/virología , Preescolar , Diarrea/diagnóstico , Diarrea/virología , Heces/virología , Gastroenteritis/diagnóstico , Gastroenteritis/genética , Genotipo , Humanos , Lactante , Recién Nacido , Norovirus/genética , ARN Viral/análisis , Reproducibilidad de los Resultados , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rotavirus/genética , Infecciones por Rotavirus/virologíaRESUMEN
Norovirus (NoV) is a major cause of epidemic gastroenteritis in industrialized countries, yet the epidemiological significance of NoV in industrializing countries remains poorly understood. The spatiotemporal distribution of NoV genotypes identified in 2054 enrolled children was investigated between May 2009 and December 2010, in Ho Chi Minh City (HCMC), Vietnam. A total of 315 NoV extracted from stool samples were genotyped and GPS mapped to their source. Genogroup II NoV, particularly GII.4, were predominant, and the GII.4 strains could be subgrouped into GII.4-2006b (Minerva) and GII.4-2010 (New Orleans) variants. There was no spatiotemporal structure among the endemic GII strains; yet a significant spatiotemporal signal corresponding with the novel introduction of GII.4-2010 variant was detected. These data show that NoV GII.4 variants are highly endemic in HCMC and describe a scenario of rapid NoV strain replacement occurring in HCMC in early 2010.