Why is dengue fever an issue now in the United States?

No one can say for sure why it turned up South Florida, but a May report from the U.S. Centers for Disease Control and Prevention in Atlanta suggests some possibilities:

Dengue might have been present in the community earlier, but is only being detected now.

The conditions for dengue transmission long have been present in South Florida. Epidemiologists say dengue could have reappeared in Florida when an infected international visitor passed the virus to local mosquitoes, or a mosquito carrying dengue hopped a ride on a cruise ship or airplane. Key West has lots of Aedes aegypti, a mosquito that is the most effective dengue carrier.

The large numbers of domestic visitors also might increase the risk for spread in other parts of the United States.

It's misleading to think there's been no dengue fever in the United States until now. In fact, in the last five years, there have been dengue outbreaks in both Florida and Texas, according to the American Society of Tropical Medicine and Hygiene.

http://abcnews.go.com/Health/ColdFlu/de ... d=11281610

Florida: Dengue Fever Outbreaks Reported

About 5 percent of the population of Key West has recently been exposed to the virus that causes dengue fever, the Centers for Disease Control and Prevention reported on Tuesday. Some people have no symptoms but some become severely ill. Dengue is common in the tropics but had been largely wiped out in the United States. There were 27 known cases in Key West in 2009, and this year there have already been 12. Officials fear that if it takes hold in Key West, it can spread to other Southern cities, where the mosquitoes that transmit it are common. There is no vaccine and no cure.


http://www.nytimes.com/2010/07/14/healt ... O_BRF.html