ATLANTA — An estimated 5% of the Key West, Fla., population—more that 1,000 people—showed evidence of recent exposure to dengue virus in 2009, according to the Centers for Disease Control and Prevention and the Florida Department of Health.
Dengue is the most common mosquito-transmitted virus and causes 25,000 deaths each year, according to the CDC. From 1946 to 1980, no cases of dengue acquired in the continental United States were reported, and there has not been an outbreak in Florida since 1934.
These cases represent the re-emergence of dengue fever in Florida (and elsewhere in the United States) after 75 years, Dr. Harold Margolis, chief of the dengue branch at CDC said at the 2010 International Conference on Emerging Infectious Diseases.
After three locally acquired cases of dengue fever were initially reported in 2009, scientists from the CDC and the Florida Department of Health conducted a study to estimate the potential exposure of the Key West population to dengue virus.
Since 1980, a few locally acquired U.S. cases have been confirmed along the Texas-Mexico border, which coincided with large outbreaks in neighboring Mexican cities. In recent years, there has been an increase in epidemic dengue in the tropics and subtropics, including in Puerto Rico, the CDC reported.
In teptember 2009, two dengue infections in Key West residents without recent travel were confirmed. By the end of 2009, 27 cases had been identified.
In a poster presented at the meeting, a total of 240 blood samples were collected from randomly selected households in Key West and tested for the presence of virus or evidence of a previous dengue infection. Among the samples, 4.95% had dengue active in their systems or had dengue antibodies. The strain was similar to strains from Mexico, according to study investigator Glen Gallagher of the CDC's dengue branch in Puerto Rico.
The take-away for physicians is that dengue fever can be a potential diagnosis even in patients without a history of travel, he said in an interview.
The CDC and the FDH continue to monitor cases in and around Key West.
Mr. Gallagher reported that he had no conflicts.
Aedes aegypti mosquitoes spread dengue virus to more than 1,000 people in Key West, Fla.
Source Courtey CDC/James Gathany