Most people with dengue do not experience any symptoms, but those who do may experience mild or severe disease, usually lasting two to seven days. The most common symptom of mild dengue is fever, which can begin four to 10 days after the bite from an infected mosquito. 

Other symptoms include:

• Rash 
• Severe headache 
• Pain behind eyes 
• Muscle and joint pain 
• Bruising 

About one in 20 people may develop severe dengue, which is a medical emergency and if not treated can result in death. Severe dengue symptoms normally occur 24-48 hours after the fever subsides and include: 

• Severe pain in the abdomen or stomach  
• Bleeding from the nose or mouth  
• Vomiting (at least three times within 24 hours)  
• Vomiting blood or pooping blood 

People can be infected with dengue through the bites of Aedes species mosquitoes carrying the virus. Mosquitoes become infected by biting a person with dengue virus in their blood. After about a week, the mosquito can spread the virus to other people when it bites. Dengue cannot spread directly from person to person. 

Less commonly, a pregnant woman can spread the dengue virus to her child during pregnancy or around the time of birth and rarely, the virus can be spread in a healthcare setting through blood transfusion, organ transplant, or by accidental needle stick injuries.