Dengue fever is a mosquito-borne disease caused by any one of four closely related dengue viruses. Symptoms of dengue fever usually begin four to six days after infection and last for up to 10 days. The symptoms may include:

• Sudden, high fever
• Severe headaches
• Pain behind the eyes
• Severe joint and muscle pain
• Fatigue
• Nausea
• Vomiting
• Mild bleeding from the nose or gums
• Bruising easily

Sometimes, symptoms are mild and can be mistaken for those of the flu or another viral infection. Younger children and people who have never had the infection before tend to have milder cases than older children and adults. However, serious problems can develop. These include dengue hemorrhagic fever, a rare complication characterized by high fever, damage to lymph and blood vessels, bleeding from the nose and gums, enlargement of the liver, and failure of the circulatory system. The symptoms may progress to massive bleeding, shock, and death. This is called dengue shock syndrome (DSS) . People with weakened immune systems as well as those with a second or subsequent dengue infection are believed to be at greater risk for developing dengue hemorrhagic fever.

It is important to note that not everyone with dengue fever will develop severe symptoms. Most people recover within a week or so. However, if you live in or are visiting an area where dengue fever is common and you have had a fever, it is important to seek medical attention if you develop any of the warning signs of severe dengue fever, which can be life-threatening. These warning signs usually begin the first day or two after your fever goes away and may include severe stomach pain, persistent vomiting, bleeding from your gums or nose, blood in your urine, stools or vomit, bleeding under the skin, which might look like bruising, difficult or rapid breathing, fatigue, irritability or restlessness.