Local Dengue Transmission in Key West, Florida

In September 2009 the Florida Department of Health (FDOH) was notified by a physician in New York about a suspected case of dengue in a New York resident who had recently returned from a trip to Key West, FL. The traveler had not recently been to any dengue endemic areas out of the US. Testing at the
CDC's Dengue Branch in San Juan, Puerto Rico confirmed an acute infection with dengue virus, serotype 1.

In response to a health alert sent to physicians in the Key West area by the Florida Department of Health, two additional suspected cases of dengue in Key West residents were identified and subsequently confirmed by the CDC's Dengue Branch. Neither of these individuals reported recent travel outside of Florida.

In response to the first apparently locally-acquired cases of dengue in Florida in many decades, the FDOH, in collaboration with the Monroe County Health Department and CDC, initiated an investigation to determine the scope of dengue virus activity and to identify risk factors for dengue infection in Key West residents. Additionally, the Florida Keys Mosquito Control district undertook intensive control activities and public education about personal protection.

The investigation had 3 components:

1. A review of medical records from the preceding 3 months at the sole medical center on Key West,
2. A randomized household serological survey which collected blood samples from 240 residents, and
3. An enhanced prospective surveillance for dengue by local health care providers with free diagnostic testing provided by the CDC’s Dengue Branch.

In total, 22 Key West residents were identified with locally-acquired dengue infections.

For more information please see: Florida Department of Health