Dengue fever is caused by one of four viruses that are transmitted by infected Aedes mosquitoes. The transmission of the disease occurs when a mosquito bites an infected person and subsequently bites an uninfected person. The bite actually transmits the small amount of blood necessary to infect someone with dengue fever. Diagnosis is made through blood tests that scan for antibodies to dengue viruses.

Infection usually becomes symptomatic 5-6 days after the infecting bite. The first symptoms are a high fever, generally 104-105 degrees F (40 degrees C), vomiting, nausea and a headache. Joint and muscular pain follow within the next days, and a flat, red rash may appear and spread from the torso to the limbs and face. The severe pains gave Dengue its nickname: break-bone fever.

Most symptoms of the disease subside within seven days of their onset, and patients are expected to make a full recovery. In a small number of cases, dengue hemorrhagic fever may develop, which has a much higher fatality rate in children and individuals with suppressed immune systems.

Every year some 20 million people contract dengue fever leading to 24,000 deaths worldwide. About 100 dengue fever infections are reported annually in the U.S., mostly from travelers returning from the tropics and residents in the southern states.

Like most viral illnesses, there is no effective cure for the disease. There are four strains of the virus and an infected person can re-experience symptoms if exposed to another strain of the virus.

The Aedes mosquito lives in tropical areas of the world including the Americas, southern Europe, North Africa, the eastern Mediterranean, Asia, Australia, various islands in the Indian Ocean, the south Pacific, the central Pacific and in the Caribbean. Travelers to these regions are advised to: wear white long sleeved shirts and long pants tucked into socks, use mosquito netting over the bed, stay away from heavily populated areas, wear mosquito repellent, and seek medical attention at the first sign of symtoms.