Most Americans have never heard of dengue fever. It is an ugly tropical disease that recently showed up in Key West, Florida. The symptoms include a fever, serious headaches, chills, muscle and joint pain and bloody urine. Although the disease is rarely fatal, it is downright unpleasant. And it is dangerous to those with a compromised immune system or other medical problems.
In the fall of 2009 an astute physician in upstate New York diagnosed dengue fever in a patient that had recently returned from a vacation in Key West. The doctor alerted county and state health officials in Florida as well as the Center for Disease Control (CDC). That triggered an investigation that uncovered 23 more cases in Key West. Everyone survived. The outbreak subsided but in April of 2010 another patient in Key West was diagnosed and hospitalized. The total so far is 28 cases.
Dengue fever is caused by a virus that is spread by mosquitoes. There is no cure. Prevention is the key – through mosquito control and personal protection. Patients typically recover on their own. But occasionally the illness turns into dengue hemorrhagic fever or dengue shock syndrome, which can be fatal.
Dengue fever is the most common mosquito-borne disease in the world. It causes up to 100 million infections and 25,000 deaths each year. Until this recent outbreak, Florida had not seen a case of dengue fever in 66 years. In fact the U.S. has not seen many cases since 1945 except for sporadic outbreaks on the Mexican border and one case in Hawaii in 2001.
Infectious disease specialists have been expecting dengue fever in the southern U.S. Two mosquitoes common to the southeastern U.S. are known carriers of the virus. Dengue cases in South America, Central America, Mexico and the Caribbean quadrupled between 1989 and 2007. A single infected traveler returning from the Caribbean, South America or Asia could trigger an outbreak.
CDC lists rapid urbanization, an increase in man-made containers that serve as mosquito breeding areas, increased international travel and lack of effective mosquito control measures as contributing factors to the increase.
No one knows exactly what caused the outbreak in Key West. But the necessary components were there. There are lots of travelers, the right kinds of mosquitoes, lots of available skin to bite, and lots of places for mosquitoes to breed. Officials suggest that mosquito control may have been a bit slack as well. The best protection is prevention. Mosquito control begins with preventing breeding, a tall order in Florida’s rainy season. Use of a good mosquito repellent is the second layer of protection.