More than two dozen cases of locally-acquired dengue fever have hit the resort town of Key West, Fla., in the past nine months, officials from the U.S Centers for Disease Control and Prevention said.
Although not the first cases of home-grown dengue in the U.S., or even in Florida, the outbreak highlights the need for physician vigilance regarding this and other formerly exotic tropical diseases, the CDC said in the May 21 issue of Morbidity and Mortality Weekly Report.
Dengue fever is a viral infection transmitted by mosquito bites. It can be debilitating, but is not usually fatal in otherwise healthy people.
It is endemic in the Western Hemisphere from Mexico southward. Most cases seen by U.S. physicians have involved travelers to such regions.
Over the past 30 years, a few cases of locally-acquired dengue have been confirmed along the Texas-Mexico border, according to the report, authored by CDC researchers, public health officials in Florida, and physicians who treated the first cases in the new Key West outbreak.
Dengue is much more of a problem elsewhere in the hemisphere, with an estimated 4.6 million cases from 2000 to 2007 in Mexico, the Caribbean, and Central and South America, according to MMWR’s editors.
But the Key West outbreak demonstrates the potential for significant penetration into the continental U.S., they suggested.
They noted that international travelers can pick up the virus in endemic areas, and are often still viremic when they return. In areas with mosquito species capable of transmitting the virus–such as Aedes aegypti and Aedes albopictus, both present in the southern and southeastern U.S.–dengue can then spread locally.