Saturday, September 4, 2010

As a longtime member of Florida's Interagency Arboviral Task Force and an expert on mosquito-borne diseases, I have been monitoring the dengue outbreak in Key West with more than a passing interest. Articles in the press, and in an editorial that appeared in this paper, suggested that the Key West dengue outbreak is being overblown. Further, the Florida Keys Mosquito Control District has been accused of fear mongering about dengue to increase the district budget.

Mosquito control budgets are rightly the provenance of elected mosquito control commissioners. It is entirely appropriate that these commissioners review and approve budgets to ensure that mosquito control has the resources to protect the public health and well-being while being cost-effective.

Accusations that raising the danger of dengue in Key West is fear mongering are counterproductive to protecting the public from this dangerous virus that is being transmitted by Aedes aegypti mosquitoes in the Old Town section of Key West. Anyone dismissing dengue only as a flulike illness is unaware of the potential severity of the disease. It can be dreadful. It is not something you want to get. It is a hemorrhagic disease, meaning you can bleed from the nose, eyes, mouth, and internal blood vessels.

The incidence of dengue in Old Town, defined as the number of cases per 1,000 people, is alarming. The incidence in Old Town in 2010 is equivalent to current dengue epidemics elsewhere. There have been 35 cases, about 28 in Old Town residents. The others were visitors.

With a population of 6,000, 4.7 in every 1,000 Old Town residents have had dengue in 2010. A Centers for Disease Control and Prevention study reported that about 5 percent of about 20,000 Key West residents were infected with dengue in 2009. With the same incidence in 2010, about 2,000 residents, or one in 10, may have been infected with a dengue type one virus since 2009.

Though these residents were likely infected in Old Town, and most showed no reportable symptoms, it is alarming that one in 10 Key West residents may be at elevated risk for severe and potentially fatal disease if Key West were invaded by another form of dengue virus, since sequential infections of different dengue viruses can cause dengue hemorrhagic fever or dengue shock syndrome.

The mosquito transmitting dengue in Old Town is found elsewhere in Florida. If the virus spreads and causes the same incidence as Old Town, say in Miami, there would be 1,700 cases and 18,000 infections! Effective mosquito control is the best hope of reducing cases, containing the Old Town epidemic before it spreads and protecting Key West and Florida.

The mosquitoes transmitting dengue inhabit houses, prefer humans for blood, breed in human water-holding containers, and bite 24/7. Therefore, many mosquito control practices that are effective against other pest mosquitoes are not as effective against this mosquito. Although the Florida Keys Mosquito Control District is effective at protecting people from other pest mosquitoes, no mosquito control district can control Aedes aegypti without active community participation to eliminate mosquito habitats in homes and businesses. It is essential that residents of Key West accept responsibility for eliminating Aedes aegypti and follow protection practices like wearing repellent to reduce contact with blood-seeking mosquitoes.

The accusations currently being hurled about in Key West are not helpful to the community. The Florida Keys Mosquito Control and the Monroe County Department of Health are doing their best to reduce dengue in Key West and Monroe County. They are doing so without essential aggressive community support, according to news coverage that downplays the health threat posed by the dengue virus.

I fear that the situation will worsen in Key West if community apathy persists. Accusations of fear mongering only encourage the public to not take needed actions and to ignore this serious disease. The media articles drawing attention to the "so what" Key West attitude are disheartening. Key West is at a moment of truth. Hurling accusations of fear mongering and not aggressively taking steps to prevent transmission only risks increased transmission and the entry and establishment of other, more severe forms of dengue.

Citizens deserve better from their leaders. How will Key West fare? Consider Fantasy Fest in October with 100,000 expected visitors. If the incidence remains high, Fantasy Fest visitors will be the main sources of blood for infectious mosquitoes. If aggressive actions are not taken now by the community, one might expect 400-500 cases and 5,000 infected people, most of them tourists!

I urge Key West's community leaders to stop the accusations, enlist the public in eliminating Aedes aegypti, and get fully behind the efforts of the Florida Keys Mosquito Control District and the Monroe County Department of Health. Key West citizens need to be working together to eliminate the risk of dengue.

Walter J. Tabachnick is director of the Florida Medical Entomology Laboratory and a professor in the Department of Entomology and Nematology at the University of Florida in Vero Beach.