Dengue epidemic in a Northeastern Brazil: random epidemiological serum survey

• Main Author: Vasconcelos, Pedro F. C.
• Publication Date: 1998
• Other Authors: Lima, José Wellington O., Rosa, Amélia P. A. Travassos da, Timbó, Maria J., Rosa, Elizabeth S. Travassos da, Lima, Hascalon R., Rodrigues, Sueli G., Rosa, Jorge F. S. Travassos da
• Format: Article
• Language: por
• Source: Revista de Saúde Pública
• Download full: https://www.revistas.usp.br/rsp/article/view/24402
• topic: Dengue^i1^sepidemiolo; Métodos soroepidemiológicos; Prevalência; Dengue^i2^sepidemiol; Seroepidemiologic methods; Prevalence

OBJECTIVE: A seroepidemiological random survey was carried out in Fortaleza city, State of Ceará, Brazil, following an epidemic of dengue virus type 2 (DEN 2), with the purpose of evaluating the frequency of clinical manifestations (signs and symptoms) and the prevalence of dengue infection. METHOD: A questionnaire calling for information on address, sex, age, clinical, epidemiological and economic status was applied to the population, followed by venupuncture collection of 5-10 ml of blood for testing by hemagglutination-inhibition (HI). The sample was calculated to obtain a prevalence of 20% with relative risk of 10% and confidence interval of 95%. All information obtained was analyzed by computer using Epi Info 5.0®, Lotus 123®, Excel 5.0®, and Stata® software. RESULTS AND CONCLUSIONS: A total of 1,341 serum samples were obtained from nine Health Districts (SD) and tested by hemagglutination inhibition. Of these, 589 (44%) were positive and 752 (56%) negative. Of the positive results, 93 primary responses (PR) (7%) to DEN-2 and 496 secondary responses (SR) (37%) were observed. The global prevalence in the SD ranged from 21% to 71%. There were 41% (243/589) asymptomatic infections and 59% (346/589) symptomatic infections. Data analysis showed no difference in frequency by sex, age, on schooling, although a highly statistically significant difference was found as between the different social classes, the infection most commonly observed being among people of better social status.The stratification of positive cases showed greater prevalence of AI (p