ABSTRACT
Two major epidemic waves of dengue 1 occurred in Rio de Janeiro, Brazil, in 1986 and 1987. This article reports the results of a survey of Rio schoolchildren who were tested serologically for antibodies to dengue 1 before and after the second major epidemic wave. The highest percentages of positive subjects were found in districts with relatively poor socioeconomic conditions and mosquito control problems. It also appears likely that the estimated number of dengue cases occurring in 1986-1987 was substantially below the number that actually occurred. In addition, because of this exposure to dengue 1, Rio de Janeiro now runs the risk of dengue hemorrhagic fever/dengue shock syndrome occurring should another dengue serotype be introduced within the next few years.
Subject(s)
Antibodies, Viral/analysis , Dengue/epidemiology , Disease Outbreaks , Adolescent , Brazil , Child , Child, Preschool , Dengue/blood , Dengue/immunology , Female , Humans , Male , Mosquito Control , Parents , Prevalence , Schools , Seroepidemiologic Studies , Serotyping , Socioeconomic Factors , Surveys and QuestionnairesABSTRACT
The detection of immunoglobulin (Ig)G and IgM antibodies to dengue 1 virus was studied by a simple enzyme immunoassay, in which infected cultured cells infected with dengue virus were used as antigen (EIA-ICC). Detection of anti-dengue 1 IgG by EIA-ICC was correlated with haemagglutination assays. EIA-ICC anti-dengue 1 IgM detection was less sensitive than IgM capture enzyme-linked immunosorbent assay. IgG and IgM responses in dengue 1 infection were studied by EIA-ICC, using sera collected at different intervals after onset of illness: IgM and IgG appeared on the 4th day of disease; the highest IgM mean titres were detected on the 7th day and IgM was not detected in sera obtained after the 60th day; the highest mean titres of anti-dengue 1 IgG were seen in sera obtained between 22 and 30 d after onset of illness. EIA-ICCs for 6 flaviviruses and 1 alphavirus were conducted with sera from patients infected with dengue 1, and primary and secondary infections of other flaviviruses. The results showed that anti-dengue 1 IgG detection was sensitive, and the antibodies were cross-reactive among the flaviviruses. Anti-dengue 1 IgM detected in dengue 1 patients was mostly type specific. The pattern of secondary dengue infection, i.e. the presence of IgG and a low titre or absence of IgM antibodies, was observed in the sera of 6 patients obtained in the first week after onset of illness. EIA-ICC is useful for dengue diagnosis, surveillance and sero-epidemiological studies.
