a1 Departamento de Virologia, Instituto Oswaldo Cruz, Fundacão Oswaldo Cruz, Avenida Brasil 4365, Rio de Janeiro 21045-360, Brazil
a2 Hospital Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
a3 Hospital Orêncio de Freitas, Niterói, Rio de Janeiro, Brazil
During 1990 and 1991, dengue fever was detected in the State of Rio de Janeiro, Brazil. It occurred in two epidemic waves; one, from January to August 1990, caused predominantly by dengue virus type 1 (DEN-1) the other from October 1990 to May 1991 caused by type 2 virus (DEN-2). Dengue was confirmed by virus isolation and/or IgM capture enzyme-linked immunosorbent assay (MAC-ELISA) in 2109/5964 (35·4%) of the cases. DEN-2 virus was isolated from 180 patients. HAI tests indicated that of these previous infection with DEN-1 had occurred in 130 (72%). The epidemic was classified as dengue fever, but severe and even fatal cases occurred in association with secondary infection.
(Accepted February 22 1993)