Dengue fever

About: Dengue fever is a research topic. Over the lifetime, 17463 publications have been published within this topic receiving 485745 citations. The topic is also known as: Dengue & dengue disease.

The Pathology of Severe Dengue in Multiple Organs of Human Fatal Cases: Histopathology, Ultrastructure and Virus Replication

Abstract: Dengue is a public health problem, with several gaps in understanding its pathogenesis. Studies based on human fatal cases are extremely important and may clarify some of these gaps. In this work, we analyzed lesions in different organs of four dengue fatal cases, occurred in Brazil. Tissues were prepared for visualization in optical and electron microscopy, with damages quantification. As expected, we observed in all studied organ lesions characteristic of severe dengue, such as hemorrhage and edema, although other injuries were also detected. Cases presented necrotic areas in the liver and diffuse macro and microsteatosis, which were more accentuated in case 1, who also had obesity. The lung was the most affected organ, with hyaline membrane formation associated with mononuclear infiltrates in patients with pre-existing diseases such as diabetes and obesity (cases 1 and 2, respectively). These cases had also extensive acute tubular necrosis in the kidney. Infection induced destruction of cardiac fibers in most cases, with absence of nucleus and loss of striations, suggesting myocarditis. Spleens revealed significant destruction of the germinal centers and atrophy of lymphoid follicles, which may be associated to decrease of T cell number. Circulatory disturbs were reinforced by the presence of megakaryocytes in alveolar spaces, thrombus formation in glomerular capillaries and loss of endothelium in several tissues. Besides histopathological and ultrastructural observations, virus replication were investigated by detection of dengue antigens, especially the non-structural 3 protein (NS3), and confirmed by the presence of virus RNA negative strand (in situ hybridization), with second staining for identification of some cells. Results showed that dengue had broader tropism comparing to what was described before in literature, replicating in hepatocytes, type II pneumocytes and cardiac fibers, as well as in resident and circulating monocytes/macrophages and endothelial cells.

Comparison of two dengue NS1 rapid tests for sensitivity, specificity and relationship to viraemia and antibody responses

Abstract: Background: Dengue is a major public health problem in tropical and subtropical countries. Rapid and easy diagnosis of dengue can assist patient triage and care-management. The detection of DENV NS1 on rapid lateral flow tests offers a fast route to a presumptive dengue diagnosis but careful evaluations are urgently needed as more and more people use them. Methods: The sensitivity and specificity of the Bio-Rad NS1 Ag Strip and SD Dengue Duo (NS1/IgM/IgG) lateral flow rapid tests were evaluated in a panel of plasma samples from 245 Vietnamese patients with RT-PCR confirmed dengue and 47 with other febrile illnesses. Results: The NS1 rapid tests had similar diagnostic sensitivities (respectively 61.6% and 62.4%) in confirmed dengue cases but were 100% specific. When IgM/IgG results from the SD Dengue Duo were included in the test interpretation, the sensitivity improved significantly from 62.4% with NS1 alone to 75.5% when NS1 and/or IgM was positive and 83.7% when NS1 and/or IgM and/or IgG was positive. Both NS1 assays were significantly more sensitive for primary than secondary dengue. NS1 positivity was associated with the underlying viraemia as NS1-positive samples had a significantly higher viraemia than NS1-negative samples. Conclusions: These data suggest that the NS1 test component of these assays are highly specific and have similar levels of sensitivity. The IgM parameter in the SD Duo test improved overall test sensitivity without compromising specificity. The SD Dengue Duo lateral flow rapid test deserves further prospective evaluation in dengue endemic settings.

Dengue Serotype-Specific Differences in Clinical Manifestation, Laboratory Parameters and Risk of Severe Disease in Adults, Singapore

Abstract: Studies on serotype-specific features of dengue and disease severity on adults are limited. We prospectively recruited adult febrile patients without alternate diagnosis to dengue from April 2005 to December 2011. Outcomes were defined using both the World Health Organization (WHO) 1997 and 2009 criteria; Dengue hemorrhagic fever (DHF) and severe dengue (SD). Infecting serotype was identified in 469 dengue-confirmed patients comprising 22.0% dengue virus serotype 1 (DENV-1), 57.1% DENV-2, 17.1% DENV-3, and 3.8% DENV-4. Cases infected with DENV-1 were more likely to present with red eyes whereas presence of joint pain and lower platelet count was associated with DENV-2 cases. After adjusting for potential confounders, DENV-1 was associated with both DHF (adjusted Relative Risk (aRR) = 1.74) and SD (aRR = 2.1) whereas DENV-2 had a lower risk of DHF (aRR = 0.5). DENV-1 genotype 1 and DENV-2 cosmopolitan were the predominant genotypes identified. Infecting dengue serotype and possibly genotype may play an important role in disease severity among adult dengue patients in Singapore.

Dengue and Hemorrhagic FeverA Potential Threat to Public Health in the United States

Abstract: MOST INDIVIDUALS IN THE UNITED STATES ARE AS little concerned about dengue fever as they were a decade ago about West Nile fever. That situation could change if dengue continues its expansion as one of the world’s most aggressive reemerging infections. After decades of absence in the United States, the sometimes deadly disease is again striking US individuals, causing an epidemic in Hawaii in 2001, appearing with increasing frequency along the Texas-Mexico border, returning with unprecedented severity in US tropical territories and commonwealths such as Puerto Rico, and striking overseas travelers. Widespread appearance of dengue in the continental United States is a real possibility. The range of Aedes albopictus (“Asian tiger mosquito”), a secondary dengue vector related to the classical vector, Aedes aegypti, has been expanding globally at an alarming rate, perhaps aided by global warming. Since its introduction into the United States in 1985, Aedes albopictus has spread to 36 states, bringing with it an increased risk of dengue outbreaks. Moreover, as dengue has reemerged throughout South and Central America and the Caribbean, its fatal form, dengue hemorrhagic fever (DHF), has appeared in many countries as well as in Puerto Rico. Between January 1, 2007, and November 30, 2007, the Pan American Health Organization received reports of 760 846 cases of dengue and 19 976 cases of DHF in the Americas. Globally, dengue and DHF case counts have been increasing steadily for more than 50 years. In the mid-1950s, annual case reports to the World Health Organization (WHO) totaled only approximately 900; by 2005, annual case reports had increased to nearly a million, submitted by more than 60 nations. Worldwide, dengue is among the most important reemerging infectious diseases with an estimated 50 million to 100 million annual cases, 500 000 hospitalizations (often requiring intensive care), and, by WHO estimates, 22 000 deaths, mostly in children. Fortunately, standardized therapy coupled with intensive education in many countries, most notably in Thailand, has greatly reduced casefatality rates. The economic and social effects of dengue are also enormous because the disease tends to occur in explosive epidemics that paralyze communities and sometimes entire nations. An explanation for why a group of viruses so well adapted to humans, having caused debilitating but nonfatal influenzalike illnesses for centuries, should suddenly expand geographically into new areas, and also turn more deadly, has proved elusive. The formidable challenges of understanding dengue pathogenesis and of developing effective therapies and vaccines must be met to effectively fight this important reemerging disease.