74 research outputs found
A New Approach to Dengue Fatal Cases Diagnosis: NS1 Antigen Capture in Tissues
Dengue manifestations may vary from asymptomatic to potentially fatal
complications. With an increasing number of Dengue Hemorrhagic fever (DHF) and
fatal cases, the availability of new approaches useful for cases confirmation
plays an important role for the disease surveillance. The diagnosis of fatal
cases in frozen and fixed tissues from autopsies can be determined by techniques
such as viral RT-PCR, in situ hybridization, viral proteins detection by
immunohistochemistry and NS3 specific immunostaining. We aimed to assess for the
first time the usefulness of NS1 capture tests as a diagnostic technique to
demonstrate DENV antigens in human tissue specimens. The highest sensitivity was
obtained by a rapid ICT which was also the most sensitive in liver, lung,
kidney, brain, spleen and thymus. Despite a number of studies demonstrating the
usefulness of DENV NS1 antigen detection by different ELISAs in plasma and/or
sera of dengue patients, no research has been done previously to demonstrate NS1
presence in tissues of fatal dengue cases. Moreover, the application of NS1 kits
to demonstrate the presence of DENV may provide a better understanding of viral
tropism in fatal cases and may be useful for studies of pathogenesis in vivo and
in experimental animals
Spatial Evaluation and Modeling of Dengue Seroprevalence and Vector Density in Rio de Janeiro, Brazil
Dengue is a major public health problem in many tropical regions of the world, including Brazil, where Aedes aegypti is the main vector. We present a household study that combines data on dengue fever seroprevalence, recent dengue infection, and vector density, in three neighborhoods of Rio de Janeiro, Brazil, during its most devastating dengue epidemic to date. This integrated entomological–serological survey showed evidence of silent transmission even during a severe epidemic. Also, past exposure to dengue virus was highly associated with age and living in areas of high movement of individuals and social/commercial activity. No association was observed between household infestation index and risk of dengue infection in these areas. Our findings are discussed in the light of current theories regarding transmission thresholds and relative role of mosquitoes and humans as vectors of dengue viruses
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