RESUMEN
BACKGROUND: The epidemiological patterns of varicella-zoster virus (VZV) infection, which are strongly associated with climate, are characterized by more frequent infections occurring among children in temperate regions than in the tropics. In temperate regions, varicella exhibits a seasonal cyclic behavior in which the number of cases increases significantly during the winter and spring seasons, further supporting the role of environmental factors in disease transmission. However, the underlying mechanisms responsible for this distinctive behavior are not fully understood. In Mexico, information regarding the epidemiology of varicella is scarce, and the distribution of VZV infection has not been analyzed. OBJECTIVES: In this article we investigate the epidemiological patterns of varicella in Mexico and their relationship with different environmental and demographic factors. STUDY DESIGN: A retrospective study was conducted using the data reported by the National Center of Epidemiological Surveillance and Disease Control. The overall varicella incidence was calculated and associated with temperature, overcrowding, age, gender and population density. RESULTS: The epidemiology of varicella showed an intriguing pattern, in which warmer regions were characterized by higher incidences than in temperate regions. Young children were the most affected age group. There was no correlation between varicella incidence and overcrowding or population density. CONCLUSIONS: The epidemiology of varicella in Mexico significantly departs from the characteristic patterns observed in other tropical latitudes, with some features resembling those commonly associated with temperate regions.
Asunto(s)
Varicela/epidemiología , Adolescente , Adulto , Niño , Preescolar , Clima , Aglomeración , Femenino , Humanos , Incidencia , Lactante , Masculino , México/epidemiología , Densidad de Población , Estudios RetrospectivosRESUMEN
The use of telaprevir and boceprevir, both protease inhibitors (PI), as part of the specifically targeted antiviral therapy for hepatitis C (STAT-C) has significantly improved sustained virologic response (SVR) rates. However, different clinical studies have also identified several mutations associated with viral resistance to both PIs. In the absence of selective pressure, drug-resistant hepatitis C virus (HCV) mutants are generally present at low frequency, making mutation detection challenging. Here, we describe a mismatch amplification mutation assay (MAMA) PCR method for the specific detection of naturally occurring drug-resistant HCV mutants. MAMA PCR successfully identified the corresponding HCV variants, while conventional methods such as direct sequencing, endpoint limiting dilution (EPLD), and bacterial cloning were not sensitive enough to detect circulating drug-resistant mutants in clinical specimens. Ultradeep pyrosequencing was used to confirm the presence of the corresponding HCV mutants. In treatment-naïve patients, the frequency of all resistant variants was below 1%. Deep amplicon sequencing allowed a detailed analysis of the structure of the viral population among these patients, showing that the evolution of the NS3 is limited to a rather small sequence space. Monitoring of HCV drug resistance before and during treatment is likely to provide important information for management of patients undergoing anti-HCV therapy.
Asunto(s)
Antivirales/farmacología , Farmacorresistencia Viral , Hepacivirus/efectos de los fármacos , Hepatitis C/virología , Mutación , Oligopéptidos/farmacología , Prolina/análogos & derivados , Adulto , Biota , Femenino , Hepacivirus/clasificación , Hepacivirus/genética , Hepacivirus/aislamiento & purificación , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa/métodos , Prolina/farmacología , Virología/métodosRESUMEN
Dengue virus (DENV) is the most important arthropod-borne viral infection in humans. Here, the genetic relatedness among autochthonous DENV Mexican isolates was assessed. Phylogenetic and median-joining network analyses showed that viral strains recovered from different geographic locations are genetically related and relatively homogeneous, exhibiting limited nucleotide diversity.
Asunto(s)
Virus del Dengue/clasificación , Virus del Dengue/aislamiento & purificación , Dengue/epidemiología , Dengue/virología , Análisis por Conglomerados , Virus del Dengue/genética , Variación Genética , Genotipo , Humanos , México/epidemiología , Epidemiología Molecular , Filogeografía , ARN Viral/genéticaRESUMEN
Several studies have identified associations between single nucleotide polymorphisms (SNPs) occurring near the interleukin-28B (IL-28B) gene and response to antiviral treatment among hepatitis C virus (HCV) patients. Here, we describe a reliable melt-mismatch amplification mutation assay (melt-MAMA) PCR-based genotyping method for IL-28B which can be used in the management of HCV patients, helping to better define the course of therapy.