A cluster of dengue cases in American missionaries returning from Haiti, 2010.

Dengue is an acute febrile illness caused by four mosquito-borne dengue viruses (DENV-1 to -4) that are endemic throughout the tropics. After returning from a 1-week missionary trip to Haiti in October of 2010, 5 of 28 (18%) travelers were hospitalized for dengue-like illness. All travelers were invited to submit serum specimens and complete questionnaires on pre-travel preparations, mosquito avoidance practices, and activities during travel. DENV infection was confirmed in seven (25%) travelers, including all travelers that were hospitalized. Viral sequencing revealed closest homology to a 2007 DENV-1 isolate from the Dominican Republic. Although most (88%) travelers had a pre-travel healthcare visit, only one-quarter knew that dengue is a risk in Haiti, and one-quarter regularly used insect repellent. This report confirms recent DENV transmission in Haiti. Travelers to DENV-endemic areas should receive dengue education during pre-travel health consultations, follow mosquito avoidance recommendations, and seek medical care for febrile illness during or after travel.