Dengue Fever Spreading to United States

Mosquitoes are responsible for the spread of many illnesses such as malaria, yellow fever and dengue fever. According to the Centers for Disease Control (CDC) about one third of the world's population lives in regions where they are at risk of catching dengue fever. Beginning with an outbreak last year, it appears that Key West, Florida, may be one of those regions.

Key West had an outbreak of dengue fever from June through October of 2009. KeysNet.com reports that out of 240 residents tested for dengue antibodies, some 99 were positive, meaning that they were exposed to the illness at one time or another. The Florida Department of Health reports 22 confirmed cases in the Key West area in 2009.

KeysNet.com, in its report on dengue, identifies a Navy sailor as testing positive for dengue fever in early April 2010.

The CDC FAQ on dengue fever states that it is an illness produced by one of four serotypes of a virus. Each serotype can produce a different version of the illness and immunity to one does not convey immunity to any of the others. In North and South America, the illness is usually transmitted through the bite of a female Aedes aegypti mosquito.

The Keys Mosquito Control District has this to say about the Aedes aegypti mosquito: "Dengue is a man-made problem with the Aedes aegypti preferring artificial containers, primarily water-holding containers around homes. Many homeowners are breeding this particular mosquito. Individuals can take simple steps to stop the spread of this virus. After each rain event and at least twice a week, walk around your yard and tip over any water-holding containers."

Henry Hagedorn, of the College of Agriculture & Life Sciences, The University of Arizona, is quoted in an on-line piece as stating: "The human link in all of this is that we create the conditions the mosquito larvae can breed in, and we provide shelter for the adults, which need protection from the heat of the day. The best way to avoid dengue fever is to reduce the access the mosquito may have to you."

The homeowner should focus on environments in and around the home that attract A. aegypti, including shrubbery that adults hide in, and places in and around the home that contain water. Window and door screens can prevent mosquitoes from entering the home. "If you have an evaporative cooler that is not well maintained, mosquitoes can breed in it," Hagedorn says.

There is no vaccine for any of the four serotypes of dengue fever. The CDC describes the symptoms as: "a sudden onset of fever, severe headache, myalgias and arthralgias, leukopenia, thrombocytopenia and hemorrhagic manifestations". Dengue fever "occasionally produces shock and hemorrhage, leading to death".

As with most viral illnesses, treatment is supportive, such as IV fluids, and for symptoms of pain and fever. Severe cases require hospitalization.

The CDC has expressed concern about the threat of dengue fever in the United States. It is already prevalent in Puerto Rico. In 2007, the CDC states, over 17 million people traveled to the United States from locations where dengue fever is endemic, potentially carrying the illness to this country. In the U.S., A. aegypti can be found as far north as New Jersey and Chicago, meaning that the potential for local outbreaks exists.