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Mosquito-Borne Illnesses: Facts, Figures and Prevention

The Keys county medical director discusses mosquito protection.

The following, based on information from the Florida Department of Health in Monroe County and the Florida Keys Mosquito Control District, is provided to address any questions:

  • Traditionally in Florida, mosquitoes are most active in summer and early fall and more dormant late fall through spring.
  • Mosquito-borne illnesses, such as dengue and chikungunya, are viral diseases primarily transmitted by the Aedes aegypti mosquito, a freshwater breed common to the southeastern United States, the Bahamas, Caribbean, Central and South America as well as other tropical and subtropical locations. These diseases are not spread person to person.
  • To help avoid being bitten by Aedes aegypti or other mosquito species, health and mosquito control officials advise using mosquito repellents that contain 20 percent to 30 percent DEET, picaridin or oil of lemon eucalyptus. DEET is not recommended for use on children younger than 2 months old. Wearing long sleeves and pants, when comfortable to do so, provides additional protection. When inside, close windows and use air conditioning. Or, if windows are open, check screens to ensure there are no holes.
  • Dengue fever and the chikungunya virus are not a health threat in the Florida Keys including Key West.
  • In 2009, cases of dengue surfaced in a small area of Key West only, likely brought in by someone bitten by a dengue-carrying mosquito outside the U.S. However, there have been no confirmed dengue fever cases in Key West since November 2010 and no health advisories were issued discouraging travel to Key West or the Florida Keys because of the virus.
  • Between overnight vacationers and cruise ship passengers, Key West hosts some 2.5 million visitors a year. There were 27 cases of dengue in 2009 and of 66 dengue cases confirmed in 2010, nine were visitors, or .000003 percent of all tourists to Key West that year. All persons — whether residents or visitors — who acquired dengue in Key West fully recovered.
  • There has never been a report of a locally acquired case of chikungunya anywhere in the Florida Keys, according to officials at the Florida Department of Health in Monroe County.
  • The Florida Keys Mosquito Control District has an aggressive mosquito suppression and abatement program. New technologies used include aerial application of an innovative larvacide that targets the mosquito larvae and stops them from reaching adulthood. The larvacide is non-toxic to humans and animals.
  • Eliminate standing water in and around homes/vacation rentals, where mosquitoes like to breed, such as coolers, flower pots, buckets or any containers that could retain rainwater.
Florida Keys Project - Working together on a new solution to reduce mosquito populations

More information is available via these links:

Or contact the Florida Department of Health in Monroe at 305-809-5653.