ABSTRACT
Background: Dengue virus infection is a major public health problem. A hypothesis put forward for severe dengue is the cytokine storm, a sudden increase in cytokines that induces vascular permeability. Previous studies and our recent meta-analysis showed that IL-6, IL-8, IFNγ, TNFα, VEGF-A and VCAM-1 are associated with dengue shock syndrome. Therefore, in this study we aim to validate the association of these cytokines with severe dengue. Methods & Findings: In a hospital based case control study in Vietnam, children with dengue fever, other febrile illness and healthy controls were recruited. Dengue virus infection was confirmed by several diagnostic tests. Multiplex Immunoassay using Luminex technology was used to measure cytokines simultaneously. A positive association with dengue shock syndrome was found for VCAM-1, whereas a negative association was found for IFNγ. Furthermore, the multivariate logistic analysis also showed that VCAM-1 and IFNγ were independently correlated with dengue shock syndrome. Conclusion: IFNγ and VCAM-1 were associated with dengue shock syndrome, although their role in the severe dengue pathogenesis remains unclear. Additional studies are required to further investigate the function of these cytokines in severe dengue.
ABSTRACT
Background: Dengue virus infection is a major public health problem. A hypothesis put forward for severe dengue is the cytokine storm, a sudden increase in cytokines that induces vascular permeability. Previous studies and our recent meta-analysis showed that IL-6, IL-8, IFNγ, TNFα, VEGF-A and VCAM-1 are associated with dengue shock syndrome. Therefore, in this study we aim to validate the association of these cytokines with severe dengue. Methods & Findings: In a hospital based-case control study in Vietnam, children with dengue fever, other febrile illness and healthy controls were recruited. Dengue virus infection was confirmed by several diagnostic tests. Multiplex immunoassay using Luminex technology was used to measure cytokines simultaneously. A positive association with dengue shock syndrome was found for VCAM-1, whereas a negative association was found for IFNγ. Furthermore, multivariate logistic analysis also showed that VCAM-1 and IFNγ were independently correlated with dengue shock syndrome. Conclusion: IFNγ and VCAM-1 were associated with dengue shock syndrome, although their role in the severe dengue pathogenesis remains unclear. Additional studies are required to shed further light on the function of these cytokines in severe dengue.
ABSTRACT
This is the first report for molecular epidemiology of DEN-4 viruses in Vietnam. At present, DEN-4 serotype can be classified into two genetically distinct types: genotypes I and II. In this study, phylogenetic analysis of DEN-4 viruses from Vietnam as well as previously published strains indicate that DEN-4 viruses could be genetically classified into more than 2 genotypes. Most recent Vietnamese DEN-4 strains (1998-2002) were clustered within a distinct genetic type, named genotype III, a newly recognized genetic type for DEN-4 viruses. In addition, two Vietnamese strains isolated in 1990 and 1997 also grouped separately forming another independent cluster in the tree, which we designated genotype IV. In this report present for the first time the existence of two new genotypes of DEN-4 in Vietnam. Evidence for local independent evolution and temporal correlation was observed.
Subject(s)
DengueABSTRACT
In 2002, DHF viro-serological surveillance was started in 19 Southern provinces of Vietnam. 247 DEN virus strains (consist of 27 DEN-1, 99 DEN-2, 9 DEN-3 and 112 DEN-4) were isolated from 3318 blood samples. The predominant serotypes were DEN-4 (45.3%) and DEN-2 (40.1%). DEN-2 virus was more positively correlated with severe cases in comparison with other serotypes. However, high rates of virus isolation were obtained from DHF grade I-II patients (49%), and then from DF, viral infection and fever of unknown origin cases (40.1%). These should be main target subjects for the active surveillance of DHF. In addition, MAC-ELISA was done on 7498 DHF serum samples taken in Southern Vietnam with the average positive rate of 44.37%
Subject(s)
Dengue , Epidemiology , LaboratoriesABSTRACT
In the year 2001, the Arbo virus Laboratory had received Dengue hemorrhagic fever samples from 19 provincial center for Preventive Medicine to isolate virus. 83 dengue viruses of 4 type were detected. Among them, the two main germs were dengue 2 and dengue 4. Viruses were detected mainly in infected children with hemorrhagic fever of I-II degree. Dengue 2 was the causative agent of DHF of I-III degree with a higher number of cases than other serotypes. 4.046 sera samples was examined by Mac ELISA, among them 56.13% was (+). However in Ma-ELISA(+) regions, there is no effective methods for dengue control.