Imported dengue--United States, 1999 and 2000.

Dengue is a mosquito-transmitted acute viral illness caused by any of the four dengue virus serotypes (DEN-1, DEN-2, DEN-3, and DEN-4). Dengue is endemic in most tropical and subtropical areas of the world and has occurred among U.S. residents returning from travel to such areas. CDC maintains a laboratory-based passive surveillance system for imported dengue among U.S. residents (laboratory-diagnosed dengue in a U.S. resident living in an area without known authochthonous dengue transmission, with travel history outside the United States in the 14 days before symptom onset). The system relies on reports by clinicians to state health departments, which forward patient specimens to CDC for diagnostic testing. This report summarizes information about imported dengue cases among U.S. residents during 1999-2000. The findings indicate that dengue continues to cause disease in U.S. travelers abroad. Travelers to tropical areas should protect themselves from mosquito bites, and health-care providers should consider dengue in the differential diagnosis of illness for patients who have returned recently from such areas.