Health Library

What Is Dengue Fever?

Dengue (DEN-gee) fever is a tropical disease caused by a virus carried by mosquitoes. The virus can cause fever, headaches, rashes, and pain throughout the body. Most cases of dengue fever are mild and go away on their own after about a week.

Dengue fever rarely strikes in the continental United States, though small outbreaks have happened in Texas, Florida, and Hawaii. But Dengue fever is common in Puerto Rico, American Samoa, and the U.S. Virgin Islands. It’s also common in many tropical countries in Central and South America, Africa, and Asia. If you plan to travel to a foreign country, especially one in the tropics, it’s wise to guard against dengue fever. Wearing insect repellent, covering sleep areas with netting, and avoiding the outdoors at dusk and dawn (when mosquitoes are most active) can help lower the chances of infection.

What Causes Dengue Fever?

Dengue fever is caused by four similar viruses spread by mosquitoes of the genus Aedes, which are common in tropical and subtropical areas worldwide.

When an Aedes mosquito bites a person who’s been infected with a dengue virus, the mosquito can become a carrier of the virus. If this mosquito bites someone else, that person can be infected with the dengue virus and can then get sick with dengue fever. The virus can’t spread directly from person to person.

In rare cases, dengue fever can lead to a more serious form of the disease called dengue hemorrhagic fever (DHF). DHF can be life-threatening and needs to be treated right away.

What Are the Signs & Symptoms of Dengue Fever?

Symptoms of dengue fever are generally mild in younger children and those who have the disease for the first time. Older kids, adults, and those who have had a previous infection may have moderate to severe symptoms.

Common signs and symptoms of dengue fever include:

• high fever, possibly as high as 105°F (40°C)
• pain behind the eyes and in the joints, muscles and/or bones
• severe headache
• rash over most of the body
• mild bleeding from the nose or gums
• bruising easily

Dengue fever used to be called “breakbone fever,” which might give you an idea of the severe bone and muscle pain it sometimes can cause. The fever isn’t actually breaking any bones, but it can sometimes feel like it is.

How Long Does Dengue Fever Last?

Symptoms can start anywhere from 4 days to 2 weeks after being bitten by an infected mosquito, and typically last for 2 to 7 days.

After the fever eases, other symptoms can get worse and may cause more severe bleeding; gastrointestinal problems like nausea, vomiting, or severe abdominal (belly) pain; and respiratory problems like difficulty breathing. Dehydration, heavy bleeding, and a rapid drop in blood pressure (shock) can follow if DHF goes untreated. These symptoms are life-threatening and need medical care right away.

Someone who’s had the illness becomes immune to that particular type of the virus (but can still be infected by any of the other three types).

How Is Dengue Fever Diagnosed?

If you think your child might have dengue fever, call a doctor right away. You should also call a doctor if your child has recently been to a region that has dengue fever and has a fever or severe headache.

To make a diagnosis, the doctor will examine your child and evaluate the symptoms. The doctor will ask about your child’s medical history and recent travels, and send a blood sample for testing.

How Is Dengue Fever Treated?

No specific treatment is available for dengue fever. Mild cases are managed with lots of fluids to prevent dehydration and getting plenty of rest. Pain relievers with acetaminophen can ease the headaches and pain from dengue fever. Pain relievers with aspirin or ibuprofen should be avoided, as they can make bleeding more likely.

Most cases of dengue fever go away within a week or two and won’t cause any lasting problems. If someone has severe symptoms of the disease, or if symptoms get worse in the first day or two after the fever goes away, get medical care right away. This could be an indication of DHF, which is a medical emergency.

To treat severe cases of dengue fever at a hospital, doctors will give intravenous (IV) fluids and electrolytes (salts) to replace those lost through vomiting or diarrhea. When started early, this is usually enough to effectively treat the disease. In more advanced cases, doctors may have to do a blood transfusion.

In all cases of dengue infection, efforts should be made to keep the infected person from being bitten by mosquitoes. This will help prevent the illness from spreading to others.

Can Dengue Fever Be Prevented?

A dengue vaccine is recommended for kids and teens 9–16 years old who have already had dengue fever and who live in the U.S. territories where it is common. It is not recommended for travelers to these areas. Visit the CDC’s site for more information.

But the vaccine is not enough on its own. Preventing mosquito bites is still very important protection. Be sure to:

• Use screens on doors and windows, and promptly repair broken or damaged screens. Keep unscreened doors and windows shut.
• Have kids wear long-sleeved shirts, long pants, shoes, and socks when they go outside, and use mosquito netting over their beds at night.
• Use insect repellent as directed on kids. Choose one with DEET or oil of lemon eucalyptus.
• Limit the amount of time kids spend outside during the day, especially in the hours around dawn and dusk, when mosquitoes are most active.
• Don’t give mosquitoes places to breed. They lay their eggs in water, so get rid of standing water in things like containers and discarded tires, and be sure to change the water in birdbaths, dog bowls, and flower vases at least once a week.

By taking these precautions and keeping your family away from areas with dengue fever outbreaks, the risk of dengue fever is small for international travelers.