Epidemiologic Studies on Dengue in Santiago de Cuba, 1997

A 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/DSS 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 island-wide dengue virus type 1 (DEN-1) epidemic of 1977-79. Virtually complete clinical and laboratory surveillance of overt disease was achieved. From December 1997 to January 1998 a random age-stratified serum sample was obtained from 1151 persons in 40 residential cluster in Santiago. Sera were 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 slightly to accommodate observed cases resulting in an estimated infection rate of 4.3%. Dengue fever and DHF/DSS attack rates were calculated from estimated total primary and secondary DEN-2 infections. Only 3% of 13116 primary infections were overt. The DHF/DSS attack rate for adults of all ages was 420 per 10000 secondary DEN-2 infections. (authors)