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Revista do Instituto de Medicina Tropical de São Paulo
On-line version ISSN 1678-9946
CUNHA, Rivaldo Venâncio da et al. Secondary dengue infection in schoolchildren in a dengue endemic area in the State of Rio de Janeiro, Brazil. Rev. Inst. Med. trop. S. Paulo [online]. 1995, vol.37, n.6, pp. 517-521. ISSN 1678-9946. http://dx.doi.org/10.1590/S0036-46651995000600008.
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.
Keywords : Dengue; secondary infection; Epidemiology; Brazil.