We report a case of dengue fever in a Boston-area health care worker with no recent history of travel but with mucocutaneous exposure to infected blood from a febrile traveler who had recently returned from Peru. Serologic tests confirmed acute dengue virus infection in both the traveler and the health care worker. We believe that this is the first documented case of dengue virus transmission via the mucocutaneous route. We present case reports and review other ways that dengue virus has been transmitted without a mosquito vector.