Epidemiologic studies on dengue in Santiago de Cuba, 1997

small, isolated outbreak of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) due to dengue virus type 2 (DEN-2) was documented in Santiago de Cuba on the island of Cuba beginning in January 1997. There were 205 DHF/DS S cases, all in persons older than age 15 years. All but three had evidence of a prior dengue infection, with the only known opportunity being the isl andwide dengue virus type 1 (DEN-1) epidemic of 1977-1979, Virtually comple te clinical and laboratory surveillance of overt disease was achieved. From December 1997 to January 1998, a random, age-stratified serum sample was o btained from 1,151 persons in 40 residential clusters in Santiago. Sera wer e tested for DEN-1 and DEN-2 neutralizing antibodies. The prevalence of DEN -2 antibodies in children age 15 years and under, born after the 1981 DEN-2 epidemic, was taken as the 1997 DEN-2 infection rate. This was adjusted sl ightly to accommodate observed cases, resulting in an estimated infection r ate of 4.3%. Dengue fever and DHF/DSS attack rates were calculated from est imated total primary and secondary DEN-2 infections. Only 3% of 13,116 prim ary infections were overt. The DHF/DSS attack rate for adults of all ages w as 420 per 10,000 secondary DEN-2 infections.