"Dengue is the most common virus that is transmitted by mosquitoes. It infects 50 million to 100 million every year, but only kills 25,000 on average. The bug causes cold or flu like symptoms that are usually very mild, leaving many cases to go undetected. However, the virus can also cause internal and external bleeding, and sudden death. A vaccine has been in the works for quite some time but nothing is concrete at this point.
27 cases of Dengue were reported in Florida in 2009, leading several organizations to investigate the appearance of Dengue in Florida. The Florida Department of Health also recently took blood samples from 240 Key West residents. Of those, 5 percent had active Dengue infections, or active antibodies to the virus, showing that at one point they had been infected."http://health.spreadit.org/dengue-in-florida-1000-exposed-272/