Dengue fever is an illness you can get from the bite of a mosquito carrying one of four types of dengue virus (DENV). The virus is most commonly found in tropical and subtropical regions, including Central and South America, Africa, parts of Asia and the Pacific Islands.

Dengue isn’t contagious from person to person except when passed from a pregnant person to their child. Symptoms are usually mild with your first infection, but if you get another infection with a different version of DENV, your risk of severe complications goes up.

Dengue is most commonly found in Central and South America, Africa, parts of Asia and the Pacific Islands. A few parts of the U.S. also have dengue. Those living in or traveling to these regions — more than half the people in the world — are most at risk. Children and those who are elderly are at higher risk for serious illness.

Most dengue infections don’t cause symptoms. If you do have symptoms, high fever (104°F/40°C) is typical, along with:

• Rash.
• Intense pain behind your eyes.
• Nausea or vomiting.
• Muscle, bone and joint pain.

Dengue fever symptoms start to appear four to 10 days after a mosquito bite and can last three to seven days. About 1 in 20 people sick with dengue will develop severe dengue after their initial symptoms begin to fade

Dengue fever is caused by one of four dengue viruses. When a mosquito infected with the dengue virus bites you, the virus can enter your blood and make copies of itself. The virus itself and your immune system’s response can make you feel sick.

The virus can destroy parts of your blood that form clots and give structure to your blood vessels. This, along with certain chemicals that your immune system creates, can make your blood leak out of your vessels and cause internal bleeding. This leads to the life-threatening symptoms of severe dengue.