Dengue epidemic in the state of Rio de Janeiro, Brazil: virological and epidemiological aspects

Abstract

Laboratory studies were carried out on 3178 patients with signs and symptoms suggestive of dengue infection from April 1986 to December 1987 in the State of Rio de Janeiro, Brazil. The epidemic had two peaks following the first virus isolation and affected the inhabitants of 17 counties. Both sex and all age groups were affected. Dengue virus type 1 was isolated from 1039 sera and the number of confirmed cases was increased to 1874 (59%) by MAC-ELISA. Isolation rate confirmed cases reached 80% in the specimens obtained until the 4th day after the onset of disease and viraemia ranged from 10(3.0) to 10(8.5) TCID50/ml.

Aedes aegypti resistance to temephos during 2001 in several municipalities in the states of Rio de Janeiro, Sergipe, and Alagoas, Brazil

“…However, in 1986 a new dengue epidemic started, in the state of Rio de Janeiro (RJ), with the serotype DEN I (Schatzmayr et al 1986) and was soon spread to the Northeast region of the country. Later, in 1990, DEN II was also detected in RJ (Nogueira et al 1990, Miagostovich et al 1993). More recently DEN III has been introduced in this state and, in the summer 2001/2002, the worst Brazilian dengue epidemics took place, starting at Rio de Janeiro and soon reaching other 11 states (Nogueira et al 2001, Barbosa-da-Silva et al 2002.…”

Comparison of dengue infection in human mononuclear leukocytes with mosquito C6/36 and mammalian Vero cells using flow cytometry to detect virus antigen

“…They include plaque forming units assay in Vero or LLC-MK2 cells (Russell et al 1967) but require relatively large amounts of virus and, most importantly, a defined cytopathic effect on cells to form plaques, unlike immunofluorescence, which can detect virus antigen without cell lysis. Detection of antigenic protein by immunofluorescence can be used to quantify virus by statistical analysis of antigen in serial dilutions in microtiterplates (Reed & Muench 1938, Shoepp & Beaty 1984) and has been used as an alternative to plaquing assays (Miagostovich et al 1993). Quantification of viral RNA by hybridization or quantitative RT-PCR (Vordam & Kuno 1997, Deubel 1997, Gubler 1998) are very sensitive methodologies but still very laborious, time consuming and costly.…”

Dengue-2 and yellow fever 17DD viruses infect human dendritic cells, resulting in an induction of activation markers, cytokines and chemokines and secretion of different TNF-α and IFN-α profiles

“…When cytopathic effects were observed seven days later, the supernatant was harvested and supplemented with 30% FCS and aliquots were frozen at -70ºC. Virus stock was titrated by serial dilution cultures in microtitre plates and detected by immunofluorescence as previously described (Miagostovich et al 1993). An uninfected flask was also maintained and the supernatant was collected to be used as a mock inoculum.…”