Dengue Fever

Dengue infection, which can cause high fever, headache, rash, severe joint and muscle pain, hemorrhage, and death, is a disease usually associated with tropical countries. Yet in the summer and fall of 2009, 22 cases of dengue infection were confirmed in Key West, Florida. Although the number of cases was small, they were noteworthy: These infections were not spread by travelers returning from endemic countries; they were the first locally transmitted infections in Florida in more than forty years. According to the National Institute of Allergy and Infectious Diseases, the risk of further dengue outbreaks in the United States is growing. Dengue infection is caused by any of four related viruses that are transmitted to humans by the mosquitoes Aedes albopictus (Asian tiger mosquito) and Aedes aegypti. Both of these bugs now live in the US. A. albopictus has been found in 36 states while A. aegypti has been found in several southern states. Experience has shown that where these mosquitoes go, dengue infection often follows.

The prospect of dengue epidemics is disturbing because there is no vaccine against dengue; nor have any specific antiviral medications shown to be effective to treat it. Dengue is a particularly tricky disease because it is caused by any one of four closely related flaviviruses. An effective vaccine would need to induce the immune system to produce antibodies against all four dengue virus serotypes, a task that so far has proven too difficult to accomplish. The fourfold dengue foe has also made the development and testing of antiviral medications complicated and expensive. Research funding for dengue and other "neglected" tropical diseases has historically been difficult to come by. Most research advances in the field of dengue prevention and treatment have come through the efforts of government agencies and pharmaceutical companies that are conducting philanthropic research. Despite these efforts, the only existing ways to prevent and control dengue infection are to control the mosquito populations responsible for transmitting the disease and to avoid being bitten by infected mosquitoes.

In this Spotlight, you will learn more about the viruses that cause dengue infection, the mosquitoes responsible for transmitting them, and the challenges scientists must overcome in order to produce a vaccine and effective dengue treatments. You will also learn about the latest research in mosquito control, including the use of genetically modified "flightless" mosquitoes. In addition, clinicians will find links to guidelines for the diagnosis, treatment, and clinical management of dengue infection — information that may be useful, in the event of future dengue outbreaks, to those who have never seen the disease in clinical practice.

Image: James Gathany/CDC.