Secondary dengue infection in schoolchildren in a dengue endemic area in the state of Rio de Janeiro, Brazil.
A seroepidemiologic survey was carried out in schoolchildren from public schools of the Niterói municipality, state of Rio de Janeiro, Brazil, after a period of sequential epidemics by dengue virus type 1 and 2 (DEN-1 and DEN-2). 450 blood samples were obtained by fingertip puncture and collected on filter paper discs. The hemagglutination inhibition (HAI) test was carried out using DEN-1 and DEN-2 antigens. HAI titres were demonstrated in 66% (297/450) of the sera and the geometric means of the titres were 1/182 and 1/71 for DEN-1 and DEN-2, respectively. Secondary infections were observed in 61% (181/297) of positive cases. Among these, 75% (135/181) were under fifteen years old. No dengue haemorrhagic fever (DHF) was reported in these children. Asymptomatic or oligosymptomatic infections were detected in 56% of the studied population. The absolute and relative frequencies of positive tests by age group and sex did not evidence statistically significant difference. The number of individuals infected probably produced a immunologic barrier responsible for the non occurrence of dengue epidemic in the latter years.
da Cunha
R V
RV
Departamento de Clínica Médica, Universidade Federal de Mato Grosso do Sul, Rio de Janeiro, Brazil.
Dias
M
M
Nogueira
R M
RM
Chagas
N
N
Miagostovich
M P
MP
Schatzmayr
H G
HG
D000293:Adolescent; D000328:Adult; D000956:Antigens, Viral / Q000097:blood; D001938:Brazil / Q000453:epidemiology; D002648:Child; D003715:Dengue / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D003716:Dengue Virus / Q000276:immunology; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D008297:Male; D012494:Sampling Studies; D016036:Seroepidemiologic Studies
D000956:Antigens, Viral