RESUMEN
Transmission of dengue virus (DENV) from mosquito to human is dependent upon the survival of the mosquito beyond the virus extrinsic incubation period. Previous studies report conflicting results of the effects of DENV on Aedes aegypti survival. Here, we describe the effect of DENV on the short-term survival (up to 12 d) of 4,321 Ae. aegypti mosquitoes blood-fed on 150 NS1-positive dengue patients hospitalized in the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. Mosquito survival was not different between cohorts that fed upon blood from which 0% of mosquitoes became DENV infected (N = 88 feeds), or 100% became infected (N = 116 feeds). Subgroup analysis also did not reveal serotype-dependent differences in survival, nor a relationship between survival and human plasma viremia levels. These results suggest that DENV infection adds minimal cost to Ae. aegypti, an important finding when parameterizing the vector competence of this mosquito.
Asunto(s)
Aedes/virología , Virus del Dengue/fisiología , Aedes/fisiología , Animales , Dengue/epidemiología , Dengue/transmisión , Interacciones Huésped-Parásitos , Humanos , Insectos Vectores/virología , Longevidad , Vietnam/epidemiologíaRESUMEN
Dengue is mosquito-borne virus infection that annually causes ~50 million clinically apparent cases worldwide. An internally controlled one-step real-time multiplex RT-PCR assay was developed for detection and quantitation of DENV RNA in plasma sample by using specific primers and fluorogenic TaqMan probes. All primers and probes targeted sequences near the 3' end of the NS5 gene. The method comprised two multiplex assays and was validated for sensitivity, specificity, linearity, reproducibility and precision. An internal control template was spiked into each clinical specimen to provide quality assurance for each experimental step. The assay allowed for detection of between 0.5 and 3 infectious particles per mL, is rapid and has been operationally characterized in 287 Vietnamese dengue patients from two therapeutic intervention trials at the Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam.
Asunto(s)
Virus del Dengue/genética , Dengue/diagnóstico , Reacción en Cadena de la Polimerasa Multiplex/métodos , ARN Viral/sangre , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Dengue/virología , Equartevirus/genética , Humanos , Límite de Detección , Técnicas Microbiológicas , Plásmidos/genética , Plásmidos/metabolismo , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Proteínas no Estructurales Virales/genéticaRESUMEN
Adjunctive treatment to improve outcome from bacterial meningitis has centered on dexamethasone. Among Vietnamese patients with bacterial meningitis, cerebrospinal fluid (CSF) opening pressure and CSF:plasma glucose ratios were significantly improved and levels of CSF cytokines interleukin (IL)-6, IL-8, and IL-10 and were all statistically significantly lower after treatment in patients who were randomized to dexamethasone, compared with levels in patients who received placebo.