What Is Dengue Fever?
Dengue (pronounced DEN-gee) fever is a mosquito-borne disease caused by any one of four closely related dengue viruses. You get dengue fever through the bite of an aedes mosquito infected with a dengue virus. The mosquito becomes infected when it bites a person with dengue virus in their blood. It can’t be spread directly from one person to another person.
About 400 million people worldwide are infected with dengue virus each year, and 100 million become mildly to severely ill with dengue fever. Most cases happen in tropical areas, such as Southeast Asia, the western Pacific islands, Latin America, and Africa. Cases in the U.S. are often in people who contracted the infection while traveling abroad. But the risk of getting dengue virus is increasing in parts of the southern U.S.
Strains of Dengue Fever
Dengue viruses come in four types, which doctors call serotypes:
- DENV-1
- DENV-2
- DENV-3
- DENV-4
All four serotypes are similar. They spread in the same parts of the world and cause the same symptoms. But each virus reacts differently to antibodies — proteins your immune system makes to protect you against germs.
Dengue Fever vs. Malaria
Malaria is another disease that spreads through the bite of infected mosquitoes in tropical countries. A different type of mosquito carries each disease. Aedes mosquitoes spread the virus that causes dengue fever. Female anopheles mosquitoes carry the parasite that transmits malaria.
Both infections cause a high fever and headache, which can make it hard to tell the two infections apart. Malaria also has symptoms such as:
- Extreme tiredness
- Seizures
- Trouble breathing
- Dark or bloody urine
- Yellowing of the eyes and skin (called jaundice)
- Abnormal bleeding
Malaria causes more deaths worldwide than dengue fever, but it is preventable and treatable. There isn’t a specific treatment for dengue fever.
Symptoms of Dengue Fever
Symptoms, which usually begin 4-10 days after infection, may include:
- High fever
- Headache
- Pain behind the eyes
- Joint, bone, and muscle pain
- Nausea
- Vomiting
- Skin rash
Sometimes, symptoms are mild and easy to mistake for those of the flu or another viral infection. Younger children and people who have never had dengue fever before tend to have milder cases than older children and adults.
Sometimes, mild cases can become more severe and turn into dengue hemorrhagic fever. It's a rare complication with symptoms such as:
- Intense stomach pain
- Vomiting that doesn't stop
- Bleeding from the nose and gums
- Blood in your pee, poop, or vomit
- Bleeding under your skin, like a bruise
- Difficulty breathing or breathing very quickly
- Tiredness
- Feeling restless or irritable
The infection may lead to severe bleeding, shock, and death. This is called dengue shock syndrome (DSS). It's important to get medical attention right away if you have these symptoms.
Diagnosing Dengue Fever
Doctors can diagnose dengue infection with a blood test to check for the virus or antibodies to it. If you become sick after traveling to a tropical area, inform your doctor. Tests can show whether a dengue infection caused your symptoms.
Dengue fever tests
A few tests can help your doctor diagnose dengue fever, such as:
Serologic or antibody tests. These tests check a sample of your blood for antibodies, which are proteins your immune system makes against viruses such as dengue virus. The MAC-ELISA test detects proteins that fight dengue fever.
Molecular tests. These tests identify genetic material from the virus. The nucleic acid amplification test (NAAT) first makes many copies of (amplifies) the virus’s DNA. Amplifying the genetic material makes it easier to find very small amounts of dengue virus in a blood sample. Polymerase chain reaction (PCR) is one type of NAAT.
Complete blood count (CBC). This test counts the number of cells in a sample of your blood. Dengue fever can cause a drop in white blood cells (which fight infection) and platelets (which prevent bleeding). A CBC can help your doctor predict how severe your infection could become.
Treatment for Dengue Fever
There is no specific medicine to treat dengue infection. If you think you may have dengue fever, take pain relievers such as acetaminophen (Tylenol). Avoid nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen (Advil, Motrin), which could worsen bleeding. Rest and drink plenty of fluids to prevent dehydration. If your symptoms are severe or they don’t improve at home, call your doctor. You may need treatment in a hospital.
Preventing Dengue Fever
The best way to prevent the disease is to avoid bites from infected mosquitoes, especially if you are living in or traveling to a tropical area. This involves protecting yourself and making efforts to keep the mosquito population down.
To protect yourself:
- Use mosquito repellents, even indoors.
- When outdoors, wear long-sleeved shirts and long pants tucked into socks.
- When indoors, use air conditioning if available.
- Make sure the window and door screens are secure and free of holes. If sleeping areas are not screened or air-conditioned, use mosquito nets.
- If you have symptoms of dengue, speak to your doctor.
To reduce the mosquito population, get rid of places where mosquitoes can breed. These include old tires, cans, or flower pots that collect rain. Regularly change the water in outdoor bird baths and pets' water dishes.
If someone in your home gets dengue fever, make an extra effort to protect yourself and other family members from mosquitoes. Mosquitoes that bite the infected family member could spread the infection to other people in your home.
Dengue vaccine
A vaccine called Dengvaxia can help prevent dengue in children aged 6 to 16 who have tested positive for the virus before and who live in areas where dengue spreads. The vaccine is about 80% effective, but children need three doses to get full protection against the virus.
The vaccine’s manufacturer, Sanofi-Pasteur, has announced that it will stop making Dengvaxia due to a lack of demand. Another vaccine called Qdenga is licensed for children aged 6 to 16, but it’s not available in the U.S. A third vaccine, TV005, is in clinical trials.
Dengue Fever Complications
Severe dengue fever can cause complications such as:
- Bleeding inside the body
- Damage to organs such as the heart and liver
- Very low blood pressure
- Breathing problems
- Seizures
- Brain inflammation
- Swelling of the testicles or ovaries
The infection can be life-threatening if you don’t treat it. If you're pregnant, you can spread the virus to your baby. Having dengue fever increases the risk of pregnancy complications such as preterm birth and low birth weight.
Dengue fever fatality rate
Worldwide, about 21,000 people die from dengue-related illness each year.
Dengue Fever Immunity
After an infection with one serotype of dengue fever, you’ll have lifelong immunity to the virus. That means you can never get sick from that type of dengue again. You’ll also be immune against the other three serotypes, but only temporarily. After a few months, you can get an infection with any of the other three types.
Takeaways
Dengue fever is a viral illness that mosquitoes spread in tropical areas of the world. The virus causes symptoms such as a high fever and painful headaches. Dengue fever is often mild and manageable at home with rest, pain relievers, and extra fluids. Severe cases may need treatment in a hospital.