GIVE

A Dangerous Precedent: Reducing Florida Mosquito Control Capabilities in the Face of Potential Catastrophic Dengue Outbreak

It has been suggested that Florida's rapid growth and prosperity can be attributed largely to efficient interstate transportation, air conditioning, and the effectiveness of Florida mosquito control. However, recent reductions in the Florida state budget have reduced Florida's commitment to support Florida mosquito control capabilities. This has occurred precisely at the time when Florida's risk from the devastating consequences of mosquito-borne disease has never been greater.

Previously I have called attention to the draconian reductions and the impacts of those reductions on Florida's mosquito control capabilities (for example see Tabachnick, WJ. 2011. What is next for Florida state aid for mosquito control? BuzzWords 11(3):8-11). The state of Florida appropriated ca. $5.5 million annually in 2007 to support Florida mosquito control. This support consisted of state aid to individual districts, funds to support the aerial dog fly program, $250,000 in a small mosquito control research program, and funds to two state universities to maintain the 2 Florida research laboratories conducting research needed to improve mosquito control. By 2011, state aid to mosquito control was cut in half, the aerial dog fly program had been eliminated (2007), and Florida A&M University closed the Public Health Entomology Research Center in Panama City eliminating 1/3 of the Florida research faculty working on mosquito control issues. The remaining laboratory, the University of Florida IFAS Florida Medical Entomology Laboratory, has lost 20% of its faculty and 80% of its technical staff due to budget reductions experienced throughout the University of Florida. All in all, nearly 60% of Florida's once proud state mosquito control infrastructure has disappeared (Fig. 1). Florida's ability to mitigate the impact of new mosquito-borne diseases through the use of new methods, targeted control, bringing new research information to bear, statewide attention to diverse regions and ecologies has been severely reduced. There has been discussion in Florida DACS to completely eliminate the state aid to mosquito control and the mosquito control research budget.

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Florida is at a crossroads. The decisions to reduce and hamper the effectiveness of Florida mosquito control are ill conceived and, frankly, dangerous. These are dangerous times for Florida's public health, well-being, and general safety. The danger to Florida from mosquito-borne disease has never been greater.

Has anyone looked at the most recent map of dengue transmission in Florida? How can one possibly look at the current dengue transmission in Florida and come to the conclusion that this is the right time to cut Florida's mosquito control funding? Fig. 2 shows the progression of mosquito transmitted dengue in Florida since 2009. Elsewhere I showed that the incidence of DENV-1 in Key West in 2010 was among the highest in the world. CDC estimated ca. 1000 residents were infected though there were only 22 recorded cases in 2009. Using the same proportions with 65 cases in 2010, ca. 3000 more residents were likely infected. In two years, 4000 infected residents among 20,000 people. One of every five Key West residents had been infected with DENV-1 since 2009.

Fig. 2. Dengue transmission in Florida 2009-11.
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Further consider that there was DENV-3 in Broward in 2010, and DENV-1 in 4 counties in 2011. The catastrophe could occur at any time. Consider DENV-3 entering Key West where ca. 4000 residents have likely already been primed for greater severity of symptoms due to their prior exposure to DENV-1. It is chilling to consider that such an event could easily produce 500 cases with 50 deaths!

Here are a few facts that we know about dengue transmission in Florida since 2009.

  1. Dengue transmission has occurred in South Florida.
  2. Multiple dengue serotypes have been detected.
  3. Vectors are present, ubiquitous, and have been very difficult to control.
  4. There has been transmission in large urban areas with the potential for large numbers of cases.

Mosquito Control capabilities must address:

  1. Urban domestic mosquitoes.
  2. Need to target resources quickly and devise control strategies for domestic mosquitoes not commonly or historically targeted.
  3. Need to galvanize the entire community to actively participate in control efforts to be successful.
  4. Need to increase capabilities through assistance from state and research agencies.

How might a looming catastrophe unfold? What might a severe dengue outbreak look like and how might Florida respond given its current reduced capabilities? The following scenario is hypothetical in the extreme and is presented only as an illustration of the events and issues we will face.

June: 2 dengue cases are reported in Key West. A Medical Alert is issued. Mosquito Control mounts a campaign targeting domestic Ae. aegypti.

July: 8 cases of dengue are reported in Miami-Dade County. A Medical Alert is issued. 4 more cases in Key West.

August: 20 cases are reported in Miami Dade. 20 cases in Key West. We learn that it is DENV-2 in Key West. 8 cases are reported in Broward. A Medical Alert is issued. 6 cases in Hillsborough. A Medical Alert is issued. County Departments of Health and mosquito control in each county issue PSA's to public; mosquito control goes door to door to educate the publis and increases its operational efforts to control Ae. aegypti or Aedes albopictus. As a result of the losses in Florida's statewide support program there is little state response or resources to assist local efforts. Communications between districts and training to provide assistance have also been reduced. There is no recent information on vectors to target high risk areas and new products are untested due to elimination of the mosquito research program.

September: 100 cases in Key West, 6 people with dengue shock syndrome, hospitals overwhelmed. 200 cases in Miami Dade. 100 cases in Broward. 100 cases in Hillsborough. Scattered cases throughout South Florida. The numbers of cases overwhelms Florida's ability to collect case information. Mosquito control is overwhelmed and is not able to determine or target at-risk populations. Tourism to Florida declines as people cancel plans to visit due to the news reports of dengue in South Florida, eventually resulting in a 10% loss of $5.7 billion of a $57 billion industry. Public health officials discuss the declaration of a Medical Threat due to dengue in South Florida. A Medical Threat is not issued because it is believed it will have little impact on reducing transmission. Florida tourism decreases because of the fears and the coverage in the media.

October : Only estimates are available on the numbers of cases due to the backlog in reporting. It is estimated that there are over 1500 cases in 4 counties. Local agencies are overwhelmed. Florida establishes emergency funding for mosquito control though plans to utilize these funds remain uncoordinated and it is unclear if this will have an impact on transmission. Communities begin campaigns to encourage citizens to assist mosquito control. Consideration of bringing added resources from adjoining districts to participate in mosquito control in the high risk areas.

No state network is in place to supervise participation in control efforts across counties and to manage logistics to ensure the effectiveness in bringing resources across districts and counties. Districts outside the dengue high risk region are cautious in providing resources until their own local risk is known with assurance, and surveillance and information to make assessments are not available. The information to effectively target larval habitats is unavailable in heavily populated areas.

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November: Estimates are there are 4000 cases in 10 Florida counties; estimated 200,000 people have been infected with a DENV serotype. Firm numbers unavailable due to reporting backlog. To date 2 serotypes are identified, DENV-1 and DENV-2. Hospitals in some areas are overwhelmed with treating patients. 50 people die.

December – February: Dry weather begins and transmission is reduced.

February –June: Sporadic low level transmission with 20 cases in the state.

June: Florida prepares for more dengue.

Florida has made draconian reductions in state support. This support has been essential for improved, timely and effective mosquito control throughout Florida.

THIS IS NOT THE TIME FOR FLORIDA TO DECREASE FLORIDA'S MOSQUITO CONTROL CAPABILITIES. IT IS THE TIME FOR VERY SERIOUS DISCUSSION ABOUT THE CONSEQUENCES OF THE DISASTEROUS DECISIONS ALREADY MADE THAT WILL CONTRIBUTE TO THE LOOMING CATASTROPHE THAT AWAITS FLORIDA DUE TO MOSQUITO-BORNE DISEASES LIKE DENGUE.

FLORIDA MUST RESTORE ITS CAPACITY TO MITIGATE SUCH AN EPIDEMIC NOW. MAKE SURE YOUR LEGISLATIVE REPRESENTATIVES ARE AWARE OF THE URGENCY.

Some may charge that I am being an alarmist. Recall that the incidence of dengue in Key West in 2010 was ca. 300/100,000 people. Fig. 3 shows what has been labeled the South Florida Metropolitan Area stretching from West Palm Beach to Miami, population estimated 5 million. The same Key West incidence from 2010 would result in 15,000 cases of dengue with ca. 600,000 people infected! Is this farfetched? Is such a risk worth the few million dollars that is needed to restore Florida's eroded mosquito control infrastructure?

   Walter J. Tabachnick, Florida Medical Entomology Laboratory
   Professor, Department of Entomology and Nematology
   University of Florida IFAS
   Vero Beach, Florida