Dengue fever is caused by four closely related dengue viruses typically found in tropical areas. Humans contract the illness by being bitten by an infected mosquito. In the Western Hemisphere, the Aedes aegypti mosquito is the most common transmitter of the disease. A more serious form of the disease, dengue hemorrhagic fever (DHF), can be fatal if it is not diagnosed and treated promptly.
Symptoms of dengue fever include high fever; severe headache; intense pain behind the eyes; joint, bone, and muscle pain; rash; and mild bleeding from the nose or gums. DHF follows a similar course, but after the fever subsides, persistent vomiting, severe abdominal pain, and difficulty breathing may develop. These symptoms mark the beginning of a more serious phase of the disease—a 24- to 48-hour period when the capillaries become permeable, causing fluid to leak out of the blood vessels. When this happens, failure of the circulatory system and shock may follow. Other signs of DHF include tendency to bruise easily, bleeding from the nose or gums, and possibly internal bleeding.
There are no specific medications for dengue fever. People with the infection should avoid aspirin and take acetaminophen instead, drink plenty of fluids, and rest. If more serious symptoms appear, it may indicate the onset of DHF. Then it is important to go to the hospital so that fluid replacement therapy can be started right away.
A vaccine has been developed and licensed in Mexico. It is recommended for individuals between the ages of 9 and 45 living in countries at high risk for the illness. The vaccine should be given in a series of three doses. Five other vaccines are under development, with two in clinical trials.
The best way to prevent an outbreak of dengue or DHF from occurring is by controlling mosquito populations. This can be done by covering containers, such as rainwater drums, where mosquitoes lay their eggs and cleaning pet and animal watering containers frequently. Air conditioning and window and door screens help prevent mosquitoes from coming indoors. Mosquito repellent can be used carefully.