Many people experience no signs or symptoms of a dengue infection. When symptoms do occur, they may be mistaken for other illnesses — such as the flu — and usually begin four to 10 days after you are bitten by an infected mosquito. Dengue fever causes a high fever — 104 F (40 C) — and any of the following signs and symptoms: 
Headache
Muscle, bone or joint pain
Nausea
Vomiting
Pain behind the eyes
Swollen glands
Rash
 Most people recover within a week or so. In some cases, symptoms worsen and can become life-threatening. This is called severe dengue, dengue hemorrhagic fever or dengue shock syndrome. Severe dengue happens when your blood vessels become damaged and leaky. And the number of clot-forming cells (platelets) in your bloodstream drops. This can lead to shock, internal bleeding, organ failure and even death. Warning signs of severe dengue fever — which is a life-threatening emergency — can develop quickly. The 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
