Inquérito soro-epidemiológico na Ilha de São Luis durante epidemia de dengue no Maranhão

Abstract

The island of São Luis in the State of Maranhão, constituted by the municipalities of São Luis-SL (835,428 inhabitants), São José de Ribamar-SJR (60,633 inhabitants) and Paço do Lumiar-PL (80,274 inhabitants), has been suffering dengue (DEN) fever epidemics since 1995, caused by DEN-1. In 1996, from August through October, an aleatory sero-epidemiologic survey was carried out in order to estimate the incidence of DEN infection and to analyze other clinical and epidemiological parameters. A questionnaire was applied and serum samples were simultaneously obtained. Serum samples were tested by hemagglutination inhibition (HI). Results were analyzed using Lotus 123, Epi-info 6.0, Excel 5.0 and STATA softwares. A total of 1,217 serum samples were obtained (101 of PL, 100 of SJR and 1017 of SL). The rate of DEN was 55.4% in PL, 28% in SJR and 41.4% in SL, suggesting the occurrence of 401,933 infections. No difference was seen between males and females, but infection occurred more in the upper social class than in poor people (p < 0.003), and was more frequent in adults than in children (p < 0.0004). In SL, the incidence was stratified into seven sanitary districts (SD), and prevalence was found to range from 26.1% in SD4 to 56.8% in SD1 (p < 0.0001). Symptoms were more frequently reported by people whose HI was positive: they included fever, headache, chills, dizziness, retrobulbar pains, muscle and joint pains, nausea, anorexia and skin rash. In spite of the high incidence of infection, no hemorrhagic cases were reported.

Dengue: twenty-five years since reemergence in Brazil

“…Thus, it is no coincidence that even only 25 years since reemergence of dengue, Brazil has become the country of the world that produces the most cases. Based on different serological surveys in the country 20,21,22 , important population contingents already have antibodies to one or more of its serotypes. Brazil has broad stretches of territory with highly favorable climate for the proliferation of Ae.…”

“…The current way of life for Brazilian urban populations has generated (on an exponential scale) the habitats for Ae. aegypti 13,24,25 to lay its eggs and thus to proliferate both in areas with deficient sanitation and in other areas with adequate sanitation, thus facilitating intense viral transmission 20,21,22 .…”

“…This apparent paradox can be observed in Brazil through the spatial distribution of seroprevalence of dengue virus infections: in some cities, the risk is high both in neighborhoods with more favorable socioeconomic conditions and in those with precarious living conditions 20,21,22 , while in other cities the poorest population has been hit more heavily 14,26,27 . In one Brazilian city, the risk of dengue virus infection, even among residents of the same neighborhood, was higher among those living in nonvertical buildings 26 .…”

“…Thus, serological surveys to determine the seroprevalence or seroincidence of dengue antibodies In order to estimate the real magni- 23 , Salvador (67%) 20 , Niterói (66%) 34 , Macapá (48.4%) 23 , Rio de Janeiro (44.5%) 30 , Fortaleza (44%) 21 , and São Luís (41.4%) 22 . Lower rates were found in Goiâ-nia (29.5%) 35 , Belo Horizonte (23.3%) 26 , and Ribeirão Preto (5.4%) 36 .…”

Detecção e tipagem de vírus dengue em Aedes aegypti (Diptera: Culicidae) na Cidade de Manaus, Estado do Amazonas

“…Resultados semelhantes foram encontrados em inquéritos soro-epidemiológicos nas Cidades de Fortaleza, CE 28 e São Luis, MA 27 , onde foi observada uma maior soroprevalência de dengue na população com maior renda. Tais achados podem ser explicados em função do hábito das pessoas mais favorecidas em cultivar plantas aquáticas e o uso de materiais descartáveis.…”