Dengue fever: a risk to travelers.

An outbreak of dengue fever occurred among a small group of Maryland and Pennsylvania residents following a trip to the British Virgin Islands in January 1996. Dengue fever is a mosquito-borne viral illness that occurs primarily in tropical urban areas. Most dengue infections are benign and self-limited, but some produce severe and fatal hemorrhagic disease. Although dengue is not endemic in the continental United States, travelers may acquire the infection during visits to the tropics. Physicians should consider dengue in the differential diagnosis of a patient with a febrile illness and a history of recent travel to a tropical area. Travelers to endemic areas should be advised to take precautions to prevent mosquito bites.