The re-emergence of Dengue Fever last year in south Florida, after an absence of 70+ years, wasn’t completely unexpected.
A little over a year ago, in a blog entitled Outnumbered By A Competent Vector I outlined the rapid spread of West Nile via mosquitoes here in the United States, and reported that scientists were worried that Dengue and Chikungunya were also candidates to spread in in the United States.
Other blogs on the subject include:
Dengue fever is a mosquito borne illness – sometimes called `breakbone fever’ – and has been on the rise around the world for the past 40 years. Dengue is caused by one of four different related viruses, and there is currently no vaccine available.
While most people recover from Dengue fever, Dengue Hemorrhagic Fever (DHF) - a more severe form of dengue infection - can be fatal if not properly treated. Even in its `mild form’, this is something you really don’t want to get.
Today the MMWR (Morbidity and Mortality Weekly Report) has a detailed study of the Key West outbreak of Dengue, including several case reports. It’s an interesting read, and I would encourage you to follow the link to read the whole thing.
I’ve excerpted a few passages, and a graph, below.
WeeklyMay 21, 2010 / 59(19);577-581
Dengue is the most common vector-borne viral disease in the world, causing an estimated 50--100 million infections and 25,000 deaths each year (1). During 1946--1980, no cases of dengue acquired in the continental United States were reported.
On September 1, 2009, a New York physician notified the Monroe County (Florida) Health Department (MCHD) and the Florida Department of Health (FDOH) of a suspected dengue case in a New York state resident whose only recent travel was to Key West, Florida. CDC confirmed the diagnosis, and a press release was issued to notify the public and Key West physicians of the potential risk for locally acquired dengue infections.
In the next 2 weeks, two dengue infections in Key West residents without recent travel were reported and confirmed. Subsequently, enhanced and active surveillance identified 24 more Key West cases during 2009. On April 13, 2010, another Key West dengue case was reported to FDOH, bringing the total to 28.
(Continue . . .)
Alternate Text: The figure above shows the number of locally acquired dengue cases (N = 28), by week of illness onset and method of identification for an outbreak in Key West, Florida, during 2009-2010. Onset dates in the 26 Key West residents ranged from July 2009 to April 2010, indicating that transmission began occurring before the August 2009 onset of symptoms in a New York resident who had traveled to Key West.
Twenty-eight cases, while concerning, does not a crisis make. But this does illustrates how easily diseases once thought conquered here in Florida can make a comeback.
Obviously, a lot of eyes will be on Key West this summer to see if additional cases show up.
And of course doctors must now be alert to the symptoms of Dengue fever, and not exclude it as a possible diagnosis simply because a patient hasn’t traveled out of the country.