This study compared the serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interferon gamma (IFN-gamma) in 78 Colombian patients, from two ethnic groups, with dengue virus infection. TNF-alpha levels were significantly higher in Afro-Colombians than in Mestizos and IL-6 levels were significantly higher in Mestizos than in Afro-Colombians, during the acute phase. IFN-gamma levels were similar in both ethnic groups. Significantly higher TNF-alpha levels were found in Afro-Colombians than in Mestizos in both dengue fever (DF) and dengue hemorrhagic fever (DHF). The IL-6 levels were higher in Mestizos than in Afro-Colombians among patients with DF, but levels of this cytokine were higher in Afro-Colombians than in Mestizos among patients with DHF. Levels of IFN-gamma were higher in patients with DHF than DF. Higher levels of these cytokines were observed in secondary infection. These results suggest that ethnicity may contribute to differences in immune responses to dengue infections.

This study compared the serum levels of IL-6, TNF-and IFN-, in children under 1 year of age with and without dengue. Sera were collected from a total of 41 children living in the Department of Antioquia, Colombia (27 patients with dengue and 14 controls). The results showed higher cytokine levels in children with dengue than without dengue, with statistically significant differences for IL-6 and IFN-. No statistically significant differences were found between clinical forms, although IL-6 and IFN-levels were higher in dengue fever cases than in dengue hemorrhagic fever cases. On the other hand, TNF-levels were higher in dengue hemorrhagic fever than in dengue fever. The levels of IL-6 and TNF-were higher in secondary infection than in primary infection, although IFN-levels were higher in primary infection. These results suggest that IL-6, TNF-and IFN-are involved in dengue infection independently of the clinical form.

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Introduction: Different dengue virus (DENV) serotypes have been associated with greater epidemic potential. In turn, the increased frequency in cases of severe forms of dengue has been associated with the cocirculation of several serotypes. Because Colombia is a country with an endemic presence of all four DENV serotypes, the aim of this study was to evaluate the in vivo and in vitro replication of the DENV-2 and DENV-3 strains under individual infection and coinfection conditions. Methodology: C6/36HT cells were infected with the two strains individually or simultaneously (coinfection). Replication capacity was evaluated by RT-qPCR, and the effects on cell viability were assessed with an MTT (3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Additionally, Aedes aegypti mosquitoes were artificially fed the two strains of each serotype individually or simultaneously. The viral genomes were quantified by RT-qPCR and the survival of the infected mosquitoes was compared to that of uninfected controls. Results: In single infections, three strains significantly affected C6/36HT cell viability, but no significant differences were found in the replication capacities of the strains of the same serotype. In the in vivo infections, mosquito survival was not affected, and no significant differences in replication between strains of the same serotype were found. Finally, in coinfections, serotype 2 replicated with a thousandfold greater efficiency than serotype 3 did both in vitro and in vivo. Conclusions: Due to the cocirculation of serotypes in endemic regions, further studies of coinfections in a natural environment would further an understanding of the transmission dynamics that affect DENV infection epidemiology.

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We identified the single nucleotide polymorphism pattern for genotype F, subgenotype F3, by in silico analysis and sequencing. Further robust in silico analyses are necessary to validate the RFLP patterns of HBV genotype and subgenotypes.

Payares R. Inmunidad colectiva contra la rubéola según una encuesta poblacional en Medellín, Colombia. Rev Panam Salud Publica. 2012;32(2):101-8. Forma de citarEl término inmunidad colectiva, poblacional o de rebaño, se refiere al efecto grupal de los programas de vacunación masiva. Se logra cuando existe una alta proporción (aunque inferior al 100%) de individuos inmunes, lo que reduce la probabilidad de contacto entre un individuo susceptible y uno infectado, evitando la transmisión de la enfermedad (1). El término "inmunidad de rebaño" fue usado por primera vez por Topley y Wilson en 1923, que sugirieron que se separara el estudio de la inmunidad individual del de la inmunidad colectiva (2).Para Theophil Lotz (3), cuando se vacuna no sólo se obtiene un beneficio individual, sino que este se extiende a las personas susceptibles no protegidas de una comunidad. La vacunación puede proteger a los individuos y generar un de 90,0% (IC95% 88,2) y el R e de 0,95 (IC95% 0,8), para una proporción ponderada de protección de 89,4% (IC95% 86,6). La protección fue menor que la P c esperada en ambos sexos, en los estratos socioeconómicos alto y bajo, y en la zona rural. En la zona urbana la protección fue mayor que la P c (89,4%, IC95% 86,7 en comparación con 87,4%, IC95% 85,8