# 4804
Early last month I wrote a blog called A Message of Import, which talked about concerns expressed by the Western Australia Health Department regarding visitors returning from Bali, Indonesia.
They warned that "Dengue fever notifications in WA have increased from 16 in 2006 to 151 in the first half of 2010, with most of these cases associated with travel to Bali. "
I then spent some time detailing the outbreak of Dengue in Key West, Florida and the prospects of Dengue being introduced into new areas by infected travelers.
I also discussed the introduction of Chikungunya to northern Italy in 2007 by a traveler returning from India.
The reality is, while once we were protected from rare, exotic diseases by vast oceans and lengthy travel times, an outbreak of an infectious disease in Asia or the Caribbean today may well be on a plane to Atlanta, London, or Sydney tomorrow.
Which brings us to the story out of Broward County, Florida late yesterday confirming a locally acquired case of Dengue Fever . . . the first in Florida outside of Key West.
You can read the details in the Sun Sentinel story First case of Broward dengue fever confirmed or the local CBS TV station report Dengue Fever Is Confirmed In Broward County but the details are basically:
An adult, who had not traveled outside of the county in weeks was diagnosed with Dengue Fever (DENV-3), and has since recovered (most Dengue cases do recover).
The county will step up mosquito control efforts and urges people to lessen their exposure to mosquito bites.
Given the incubation period of Dengue, it is pretty certain this person contracted the virus from a local mosquito . . . and that mosquito could only have gotten the virus by biting someone who was already infected.
Interestingly, the serotype detected in this case is reportedly DENV-3, which is not the same as has been detected in Key West (DENV-1).
DENV-3 hasn’t been among the serotypes detected in Puerto Rico this year, either - which would argue against the importation of the virus from that island as well.
Which leads local officials to believe that this virus was introduced to Broward county by an infected traveler recently arrived from the Caribbean, Central, or South America (or some other country where that serotype is found).
The recent importation of Dengue to South Florida isn’t a complete surprise, given the amount of international travel to and from that region, and the favorable environment (weather, urban population, ample mosquito vectors) for its spread.
The CDC’s MMWR in a report last May on Locally Acquired Dengue in Key West, had this to say:
Cases of dengue in returning U.S. travelers have increased steadily during the past 20 years (8). Dengue is now the leading cause of acute febrile illness in U.S. travelers returning from the Caribbean, South America, and Asia (9).
Many of these travelers are still viremic upon return to the United States and potentially capable of introducing dengue virus into a community with competent mosquito vectors.
None of this means to suggest that Dengue has taken up permanent residence in Broward County. It would take the detection of a lot more locally acquired cases before that becomes a concern.
In fact, it may take many introductions of Dengue to an area before the right combination of weather, insect vectors, and ongoing transmission occur to enable it to get a foothold in a community.
What this does highlight is the need to pursue aggressive mosquito control measures and to instill good mosquito protection habits in the population.
And it isn’t just for Dengue.
The latest Florida Arbovirus Surveillance report (Aug 7th) lists the following Year-to-Date summary:
Eastern Equine Encephalitis Acquired in Florida: Four human cases of EEE have been reported in 2010 in Hillsborough (2), Wakulla, and Leon counties with onset dates in June (1) and July (3).
Dengue Acquired in Florida: Twenty-five cases of dengue have been reported as acquired in Key West in 2010. Of these, 18 are Key West residents, six are residents of other Florida counties, and one resides out of state. Onset dates ranged from March 17 to July 22, 2010.
Imported Dengue: Fifty-seven cases of dengue with onset in 2010 have been reported in individuals with travel history to a dengue endemic country in the two weeks prior to onset.
Imported Malaria: Sixty-five imported cases of malaria with onset in 2010 have been reported.
I’ve stated often that as a native Floridian, I don’t live in fear of being bitten by a mosquito. I understand that the odds of acquiring a disease that way are actually very small.
But I do take reasonable precautions, and try to remember to follow the `5 D’s’:
Don't go outdoors at DUSK and DAWN when mosquitoes are most active.
DRESS so your skin is covered with clothing
Apply mosquito repellent containing DEET to bare skin and clothing.
Other effective repellents include picaridin, oil of lemon eucalyptus, and IR3535
Empty containers and DRAIN standing water around your home where mosquitoes can lay eggs.