[Future prospects in developing of dengue vaccines]. / Perspectivas futuras en el desarrollo de vacunas para dengue.

Dengue is a viral, febrile and acute disease that causes more morbility than any other infection for Arbovirus. It becomes necessary to implement a safe and effective vaccine that will contribute to the eradication of this disease, especially in endemic areas with very low socio-economic conditions. The only option that exists at the present to control the transmission of the disease is through vector control. So far, there are no effective antiviral drugs for flavivirus such as dengue. Candidates for vaccines for this disease, who are currently in advanced stages of development, are live attenuated vaccine, live attenuated chimerics, inactivated virus, subunits and DNA, in order to mimic the natural infection. The requirements for an ideal vaccine capable of protecting the population at risk should be: free reactogenicity, one which induces protection against all four serotypes of the virus (tetravalent), that offers effective prolonged protection; it also should be highly immunogenic, with few side effects, easy administration, available at low cost and should be administered in one dose, both in adults and in children. Meanwhile, efforts to try to give immunoprophylaxis for this disease continue, in order to design an ideal vaccine allowing the eradication of the disease and the reduction in the number of cases which affects our people every day.

[Increase of interleukin-1 beta, gamma interferon and tumor necrosis factor alpha in serum and brain of mice infected with the Venezuelan Equine Encephalitis virus]. / Incremento de interleucina-1 beta, interferon gamma y factor de necrosis tumoral alfa en suero y cerebro de ratones infectados con el virus de Encefalitis Equina Venezolana.

Considerable efforts have been directed to clarify the main protective and recovery mechanisms in acute viral infections and, the possible role of the cytokines involved in the primary immune response induced by an epizootic strain of the Venezuelan Equine Encephalitis (VEE) virus. This study examined the levels of TH1 cytokines Interleukin-2 (IL-2) and Interferon-gamma (IFN-gamma), TH2 cytokines Interleukin-4 (IL-4) and proinflammatory cytokines (IL-1beta, TNF-alpha) in serum and brain of mice infected with the VEE virus during different post infection periods. NMRI albino male mice infected with a suspension (10 DL50) of the Guajira strain of the VEE virus, and a control group (without infection) were used. At one, 3 and 5 days post-infection, whole blood and brains were extracted to obtain sera and brain homogenates, respectively. IL-2, IFN-gamma, IL-4, IL-beta and TNF-alpha were determined by ELISA. A significant increment in the levels of IL-1beta, IFN-gamma and TNF-alpha was observed (p<0.01) in serum and brain homogenates at 1, 3 and 5 day post-infection, when compared with the control group. The levels of IL-2 and IL-4 did not show any significant statistical difference when compared to the controls. These results suggest that IL-1beta, IFN-gamma and TNF-alpha, could be involved in the early immunitary response to VEE virus during the primary infection.

Differential induction of cytokines by human neonatal, adult, and elderly monocyte/macrophages infected with dengue virus.

Immunosuppressive status against infections in monocytes from neonates and elderly subjects has been reported. The interaction between dengue virus and monocytes/macrophages plays an important role during dengue disease. The aim of this study was to determine the cytokine response of monocytes from individuals with different ages after infection with dengue virus. Monocyte/macrophage cultures from neonatal, adult, and elderly subjects (n=10 each group) were incubated with all four dengue virus types (DENV-1 to -4). After 1 and 3 days of culture, cytokine concentrations (TNF-α, IL-6, and IL-1ß) were determined in culture supernatants by enzyme-linked immunosorbant assay. Increased production of all studied cytokines was induced by the different viral types in monocyte/macrophage cultures regardless of their source. However, lower cytokine concentrations were found in neonatal and elderly monocytes. The relative monocyte/macrophage immunosuppressive status observed in neonates and the elderly could be relevant during dengue infection in those age groups and important in innate and adaptive immunity responses against this virus.

Differential oxidative stress induced by dengue virus in monocytes from human neonates, adult and elderly individuals.

Changes in immune response during lifespan of man are well known. These changes involve decreased neonatal and elderly immune response. In addition, it has been shown a relationship between immune and oxidative mechanisms, suggesting that altered immune response could be associated to altered oxidative response. Increased expression of nitric oxide (NO) has been documented in dengue and in monocyte cultures infected with different types of dengue virus. However, there is no information about the age-dependent NO oxidative response in humans infected by dengue virus. In this study, monocyte cultures from neonatal, elderly and adult individuals (n = 10 each group) were infected with different dengue virus types (DENV- 1 to 4) and oxidative/antioxidative responses and apoptosis were measured at days 1 and 3 of culture. Increased production of NO, lipid peroxidation and enzymatic and nonenzymatic anti-oxidative responses in dengue infected monocyte cultures were observed. However, neonatal and elderly monocytes had lower values of studied parameters when compared to those in adult-derived cultures. Apoptosis was present in infected monocytes with higher values at day 3 of culture. This reduced oxidant/antioxidant response of neonatal and elderly monocytes could be relevant in the pathogenesis of dengue disease.

Increment of interleukin 6, tumour necrosis factor alpha, nitric oxide, C-reactive protein and apoptosis in dengue.

This study evaluated the levels of TNFalpha, IL-6, IL-1beta, nitric oxide (NO), CRP, C3 and apoptosis in 36 patients with dengue fever (DF), 34 patients with dengue haemorrhagic fever (DHF) and in virus-infected monocyte cultures. IL-6, TNFalpha, NO (nitrites) and CRP levels were increased and C3 diminished in patients with DF and DHF. IL-6, TNFalpha, CPR and C3 values were associated with disease severity (DHF). Nitrite content was incremented in DF patients. TNFalpha, NO and CRP levels were associated with secondary infection. IL-6 and CRP levels were associated with dengue virus type 4 (DENV-4) and DENV-2, respectively. Low levels of C3 were associated with DENV-2 and DENV-4 infections. Similarly, increased content of TNFalpha, IL-6 and nitrites were observed in supernatants from infected monocyte cultures. IL-6 was associated with DENV-4 infection. The different virus serotypes induced apoptosis in monocyte cultures. Dengue infection did not induce elevated IL-1beta production, either in patients or in infected cultures. These results suggest that TNFalpha, IL-6, NO and CRP are involved in dengue infection and that monocytes could be an important source of cytokine and NO production.

Concentraciones séricas de zinc en embarazadas preeclámpticas y normotensas / Serum concentrations of zinc in pregnant preeclamptic and normotensive

Objetivo: Comparar las concentraciones séricas de zinc en embarazadas preeclámpticas y normotensas. Métodos: Investigación de tipo correlacional, comparativa y aplicada, con diseño de casos y controles. La cual incluyó a 40 mujeres en el tercer trimestre del embarazo con diagnóstico de preeclampsia y a 40 embarazas normotensas; tanto a los casos como a los controles se les determinó las concentraciones séricas de zinc, mediante la espectrofotometría de absorción atómica. Ambiente: Hospital Materno Infantil “Dr. Raúl Leoni” de Maracaibo. Resultados: Se encontró que las pacientes preeclámpticas presentaban significativamente concentraciones más bajas de zinc que las normotensas (P<0,05), aunque con medias dentro de rangos normales en ambos grupos (76,42±5,29 vs. 80.37±2,7); presentando diferencias altamente significativas en la presión arterial media entre los casos y los controles (P< 0,001). Asimismo, se constató que no existía relación entre las variables presión arterial media y concentraciones séricas de zinc en las preeclámpticas (P> 0,05); mientras que en las normotensas se evidenció una relación significativa e inversamente proporcional (r = - 0,319; P<0,05). Conclusiones: Las embarazadas con preeclampsia presentaban significativamente menores concentraciones séricas de zinc que las normotensas; sin embargo, no existe relación entre la presión arterial media y el zinc.

Objective: To compare serum concentrations of zinc in preeclamptic and normotensive pregnant. Methods: We performed a correlational, comparative and applied type research, with a not experimental, case-control, contemporary transactional and field design, which included 40 women in the third trimester of pregnancy with diagnosis pre-eclampsia and 40 normotensive pregnant; both cases as controls were analyzed for serum concentrations of zinc by atomic absorption spectrophotometry. Setting: Hospital Materno Infantil “Dr. Raul Leoni” in Maracaibo, Venezuela. Results: We found that preeclamptic patients had significantly lower concentrations of zinc to the normotensive (P <0.05), although average within normal ranges in both groups (76.42 ± 5.29 vs. 80.37 ± 2.7), presenting highly significant differences in mean arterial pressure between cases and controls (P <0.001). Also found no relationship between the variables mean arterial pressure and serum zinc concentrations in preeclamptic (P> 0.05), whereas in the normotensive group showed a significant and inversely proportional relationship (r = - 0.319, P <0.05). Conclusion: Pregnant women with pre-eclampsia had significantly lower serum zinc concentrations than normotensive, but there was no relationship between mean arterial pressure and zinc.

Bacterias enteropatógenas en la comunidad étnica añu de la Laguna de Sinamaica, Estado Zulia, Venezuela / Enteropathogenic bacteria in the añu ethnic community from Laguna de Sinamaica, Zulia State, Venezuela

Los estudios poblacionales sobre prevalencia de enteropatógenos bacterianos son escasos, particularmente en comunidades indígenas. En el presente estudio se investigó la prevalencia de bacterias enteropatógenas en muestras de materia fecal correspondientes a 378 individuos de la etnia añu, de diferente edad y género, residentes en la Laguna de Sinamaica, estado Zulia. Se realizó el cultivo bacteriológico convencional, excluyendo las categorías diarreogénicas de Escherichia coli. Se obtuvieron 71 cultivos positivos (18,8%), con predominio de las infecciones por un solo agente (58 casos, 81,7%), aunque también se detectaron asociaciones entre dos o tres especies (15,5% y 2,8%, respectivamente). En total se aislaron 86 cepas bacterianas, cuya distribución fue la siguiente: Aeromonas spp.: 34 aislamientos (39,5%), Vibrio spp.: 27 (31,4%), Shigella spp.: 11 (12,8%), Campylobacter spp.: 9 (10,5%), Plesiomonas shigelloides: 3 (3,5%) y Salmonella enterica: 2 (2,3%). V. parahaemolyticus resultó la especie predominante (15/86; 17,4%). El riesgo de infección por bacterias enteropatógenas resultó 2,6 veces superior para niños lactantes y preescolares (p < 0,01). La mayoría de los individuos participantes negó presentar sintomatología gastrointestinal. Los resultados demuestran una alta prevalencia de enteropatógenos bacterianos entre la población añu estudiada, con una distribución mayoritaria de las especies que habitualmente forman parte de la microbiota normal de las aguas.

Population studies on prevalence of enteropathogenic bacteria are few, especially in indigenous communities. In the present study we investigated the prevalence of enteropathogenic bacteria in feces samples corresponding to 378 individuals from the añu ethnic community with various ages and gender, living at the Laguna de Sinamaica, Zulia State. A conventional bacteriological culture was done, excluding Escherichia coli diarrheogenic categories. Seventy one positive cultures were obtained (18.8%) with predominance of single agent infections (58 cases, 81.7%), even though associations between two or three species were also detected (15.5% and 2.8% respectively). A total of 86 bacterial strains were isolated, with the following distribution: Aeromonas spp, 34 (39.5%) isolates; Vibrio spp, 27 (31.4%); Shigella spp, 11 (12.8%); Campylobacter spp, 9 (10.5%); Plesiomonas shigelloides, 3 (3.5); and Salmonella enterica, 2.3%). V. parahaemolyticus turned out to be the predominant species (15/86, 17.4%). The enteropathogenic bacterial infection risk was 2.6 higher for lactating and preschool children (p< 0.01). Most of the participating individuals denied presence of gastrointestinal symptoms. The results showed a high prevalence of bacterial enteropathogens in the añu population studied, with a mayor distribution of the species which habitually are part of normal water microbiology.

Incremento de interleucina-1 beta, interferon gamma y factor de necrosis tumoral alfa en suero y cerebro de ratones infectados con el virus de encefalitis equina venezolana / Increase of interleukin-1 beta, gamma interferon and tumor necrosis factor alpha in serum and brain of mice infected with the venezuelan equine encephalitis virus

Diversos esfuerzos han sido dirigidos a fin de esclarecer los principales mecanismos de protección y recuperación en las infecciones virales agudas y el posible papel de las citocinas involucradas en la respuesta inmunitaria primaria inducida por una cepa epizoótica del virus de Encefalitis Equina Venezolana (EEV). En el presente estudio se determinaron las concentraciones de citocinas TH1 Interleucina-2 (IL-2) e Interferon-gamma (IFN-g), TH2 Interleucina-4 (IL-4), proinflamatorias (IL-1b) y el Factor de Necrosis Tumoral -alfa (TNF-a) en suero y cerebro de ratones infectados con el virus de EEV a diferentes períodos de infección. Se utilizaron ratones NMRI albinos machos infectados con una suspensión (10 DL50) de la cepa Guajira del virus de EEV, y un grupo control (sin infectar). En los días 1, 3 y 5 post-infección, se extrajo sangre completa de ratones para la obtención de suero y el cerebro previa perfusión, para la obtención de homogeneizados cerebrales. En ambas muestras se determinaron IL-2, IFN-g, IL-4, IL-1b, y TNF-a por la técnica de ELISA. Se observó un incremento significativo (p < 0,01) en suero y homogeneizados cerebrales al 1er, 3er y 5to día post-infección en las concentraciones de IL-1b, IFN-g y TNF-a, al compararlos con el grupo control. La cuantificación de IL-2 e IL-4, no arrojaron diferencias estadísticamente significativas al ser comparados con los controles. Estos resultados sugieren que la IL-1b, IFN-g y TNF-a, podrían estar involucradas en la respuesta inmunitaria temprana al virus de EEV durante la infección primaria.