MMWR. 1995;44:353-356 1 table omitted DENGUE is a mosquito-transmitted acute disease caused by any of four virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4) and characterized by the sudden onset of fever, headache, myalgia, rash, nausea, and vomiting. The disease is endemic in most tropical areas of the world and has occurred in U.S. residents returning from travel to such areas. This report summarizes information about cases of imported dengue among U.S. residents during 1993 and 1994. Serum samples from 148 U.S. residents who had suspected dengue with onset in 1993 (57 cases) and 1994 (91 cases) were submitted to CDC for diagnostic testing from 33 states. Of these, 46 (31%) cases from 17 states were serologically or virologically diagnosed as dengue1by isolation of dengue virus, detection of dengue-specific IgM, single high titers of IgG antibodies in acute serum samples, or a fourfold or greater rise in dengue-specific antibodies