Many people, especially children and teens, may experience no signs or symptoms during a mild case of dengue fever. When symptoms do occur, they usually begin four to 10 days after you are bitten by an infected mosquito. Signs and symptoms of dengue fever most commonly include:
- Fever, as high as 106 F (41 C)
- Muscle, bone and joint pain
- Pain behind your eyes
You might also experience:
- Widespread rash
- Nausea and vomiting
- Rarely, minor bleeding from your gums or nose
Most people recover within a week or so. In some cases, symptoms worsen and can become life-threatening. Blood vessels often become damaged and leaky. And the number of clot-forming cells (platelets) in your bloodstream drops. This can cause:
- Bleeding from your nose and mouth
- Severe abdominal pain
- Persistent vomiting
- Bleeding under the skin, which might look like bruising
- Problems with your lungs, liver and heart
When to see a doctor
If you've recently visited a region in which dengue fever is known to occur and you suddenly develop a fever, see your doctor.
Dengue fever is caused by any one of four dengue viruses spread by mosquitoes that thrive in and near human lodgings. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito. When the infected mosquito then bites another person, the virus enters that person's bloodstream.
After you've recovered from dengue fever, you have immunity to the virus that infected you — but not to the other three dengue fever viruses. The risk of developing severe dengue fever, also known as dengue hemorrhagic fever, actually increases if you're infected a second, third or fourth time.
Factors that put you at greater risk of developing dengue fever or a more severe form of the disease include:
- Living or traveling in tropical areas. Being in tropical and subtropical areas increases your risk of exposure to the virus that causes dengue fever. Especially high-risk areas are Southeast Asia, the western Pacific islands, Latin America and the Caribbean.
- Prior infection with a dengue fever virus. Previous infection with a dengue fever virus increases your risk of having severe symptoms if you're infected again.
If severe, dengue fever can damage the lungs, liver or heart. Blood pressure can drop to dangerous levels, causing shock and, in some cases, death.
Six dengue fever vaccines are in development, but not yet available. The vaccine that's furthest in development is a three-dose vaccine for children. The results of a phase III trial were published in July 2014. This study showed that the vaccine appears to be safe, and it prevented dengue infections slightly more than half the time.
Those who had the vaccine but still became infected with dengue had a milder course of the disease than did those who weren't vaccinated. Although the vaccine is not as effective as doctors would like, it is safe. The company that makes this vaccine hasn't yet announced any plans to seek approval to market the vaccine.
So for now, if you're living or traveling in an area where dengue fever is known to be, the best way to avoid dengue fever is to avoid being bitten by mosquitoes that carry the disease.
If you are living or traveling in tropical areas where dengue fever is common, these tips may help reduce your risk of mosquito bites:
- Stay in air-conditioned or well-screened housing. It's particularly important to keep mosquitoes out at night.
- Reschedule outdoor activities. Avoid being outdoors at dawn, dusk and early evening, when more mosquitoes are out.
- Wear protective clothing. When you go into mosquito-infested areas, wear a long-sleeved shirt, long pants, socks and shoes.
- Use mosquito repellent. Permethrin can be applied to your clothing, shoes, camping gear and bed netting. You can also buy clothing made with permethrin already in it. For your skin, use a repellent containing at least a 10 percent concentration of DEET.
- Reduce mosquito habitat. The mosquitoes that carry the dengue virus typically live in and around houses, breeding in standing water that can collect in such things as used automobile tires. Reduce the breeding habitat to lower mosquito populations.