What Is Dengue Fever?
Dengue (DENG-gey) fever is a mosquito-borne illness that occurs in tropical and subtropical areas of the world. Dengue viruses are spread to people through the bite of an infected Aedes species ( aegypti or albopictus) mosquito. These mosquitoes also spread Zika, chikungunya, and other viruses.
Mild dengue fever causes a high fever and flu-like symptoms. The severe form of dengue fever, also called dengue hemorrhagic fever, can cause serious bleeding, a sudden drop in blood pressure (shock) and death.
 |
| What Is Dengue Fever? |
Almost half of the world’s population, about 4 billion people, live in areas with a risk of dengue. Dengue is caused by one of any of four related viruses: Dengue virus 1, 2, 3, and 4. Due to this reason, a person can be infected with a dengue virus as many as four times in his or her lifecycle.
Who does dengue fever affect?
Dengue is most commonly found in Central and South America, Africa, parts of Asia and the Pacific Islands. Some parts of the U.S. also have dengue. Those living in or traveling to these regions, almost more than half the people in the world are at risk. Children and those who are elderly are at higher risk for serious illness.
How common is dengue ?
In studies it is found nearly 400 million people get infected with dengue every year, but most (about 80%) have no symptoms.
Can you be immune to dengue fever?
Yes, you can get immunity to a version of dengue virus once you’ve been infected with it. Because there are at least four versions (strains) of the virus (DENV).
Our immune system is efficient to recognize infections and get better at fighting them off. As our body fights a virus, it uses antibody to fight with the virus .
Antibodies are specific to each harmful invader to our body, fitting to them like a key to a lock. Antibodies grab onto their specific target and our immune system destroys it. Once our body knows how to fight that specific virus, we are unlikely to get sick with it again.
After getting one of the four strains of DENV, we shouldn’t be able to get that one again. But the antibodies for that strain don’t fit other versions quite perfectly. So if we get infected by a different version of DENV later on, it can actually use this imperfect fit to trick our immune system (antibody-dependent enhancement).
The different strain can get caught by the antibody from the first strain we had and get pulled into our cells, but — for reasons not fully understood — it’s not destroyed. It’s then inside our cells without our cells knowing it’s harmful. This makes it easier for the virus to infect us and cause more serious illness.
SYMPTOMS AND CAUSES
What are the symptoms of dengue fever?
Most dengue infections don’t cause symptoms. If we 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.
Severe dengue (dengue hemorrhagic fever)
Severe dengue is a life-threatening worsening of dengue symptoms. Warning signs of severe dengue are usually seen 24 to 48 hours after our fever goes away.
Severe dengue is a medical emergency that can be fatal. If we have dengue or live in an area where dengue is common, go to the nearest ER immediately if we experience any of these symptoms:
Stomach/abdominal pain.
Frequent vomiting.
Throwing up blood or blood in our poop (stool).
Nose bleeds or bleeding gums.
Extreme tiredness, restlessness or irritability.
What causes dengue fever?
Dengue fever is caused by one of four dengue viruses. When a mosquito infected with the dengue virus bites us, the virus can enter our blood and make copies of itself. The virus itself and our immune system’s response can make us feel sick.
The virus can destroy parts of our blood that form clots and give structure to our blood vessels. This, along with certain chemicals that our immune system creates, can make our blood leak out of our vessels and cause internal bleeding. This leads to the life-threatening symptoms of severe dengue.
How does dengue fever spread?
Dengue is spread by Aedes mosquitos, which also carry viruses like Zika and chikungunya. The mosquitos bites someone with dengue fever and then bites someone else, causing them to become infected.
Is dengue fever contagious?
Dengue fever isn’t contagious directly from one person to another like the flu. The only way to get dengue from another person is if a pregnant person becomes infected. If you’re pregnant and get dengue, she can pass it to her baby during pregnancy or childbirth.
How is dengue fever diagnosed?
Dengue fever is diagnosed with a blood test. Our healthcare provider will take a sample of blood through a vein and send it to a lab to look for signs of dengue virus. This may also identify which of the four versions we have. Our provider can use a blood test to look for other viruses that cause similar symptoms.
MANAGEMENT AND TREATMENT
How is dengue fever treated?
There’s no medicine that treats dengue fever. Our healthcare provider will give us recommendations on how to manage our symptoms and if and when we should go to the ER.
How do I manage the symptoms of dengue fever?
Managing our symptoms is the only way to treat dengue fever. Follow our healthcare provider’s recommendations, which may include:
- Keeping ourself hydrated by drinking plenty of water and fluids.
- Getting as much rest as possible.
- Treating pain with acetaminophen .
- Do not take ibuprofen or aspirin. This can increase our risk of life-threatening internal bleeding.
PREVENTION
How can I reduce my risk of dengue fever?
The two main ways to protect ourself from dengue are through avoiding mosquito bites and vaccination.
Mosquito protection
The best way to reduce our risk of dengue fever is to protect ourself from mosquito bites:
Use insect repellents that contain 20% to 30% DEET or other ingredients known to help keep Aedes mosquitos away. Cover exposed skin outdoors, especially at night when mosquitos are more likely to be around. Remove standing water (buckets or barrels, bird baths, old tires that may hold rainwater) and fill low spots where water can pool. Keep mosquitos outside of our home by repairing holes in screens and keeping windows and doors closed if possible. Use mosquito netting at night in areas where dengue is common.
If you’re pregnant, avoid traveling to areas where dengue is common if possible.
Dengue vaccine
The dengue vaccine (Dengvaxia) is recommended only if we have already had dengue before. It can reduce our risk of severe dengue (dengue hemorrhagic fever) if we get a different version of the dengue virus in the future.
Getting the vaccine isn’t recommended if we’ve never had dengue before. Because getting infected once with dengue makes us more likely to get sicker if we get another version of the virus (antibody-dependent enhancement), getting vaccinated before having dengue for the first time can increase our risk of severe dengue. Our doctor will do a blood test to check for signs of a previous dengue infection to confirm that we’ve had dengue before getting the vaccination.
FAQ
What can I expect if I have dengue fever?
Most cases of dengue fever don’t have symptoms or the symptoms are mild, but sometimes we can have a more serious case that requires immediate medical attention.
How long does dengue fever last?
Initial symptoms of dengue last three to seven days. Most people begin to feel better after this, but some have life-threatening severe dengue that requires treatment in a medical facility.
Can we survive dengue fever?
Most people recover from dengue fever without any lasting complications. If we have symptoms of dengue fever, we have about a 1 in 20 chance of it worsening to severe dengue. If we have severe dengue and are treated immediately at a hospital or medical facility, we have a greater than 99% chance of recovering.
Complications of dengue fever in pregnancy
If you’re pregnant and have dengue fever, it can cause miscarriage, low birth weight or premature birth. It’s important to take steps to prevent getting dengue during pregnancy to protect yourself and your unborn child.
Can we get dengue fever multiple times?
Yes. Because there are at least four versions (strains) of the dengue virus, we can get dengue more than once.
We’ll usually become immune to the first strain we get sick with and can’t get it again. But we can get sick with one of the other three strains after that. In fact, we’re more likely to get severely sick if we get dengue more than once.
How do I take care of ourself if we’ve had dengue?
If we’ve had dengue before, we’re more likely to become seriously ill if we get a different version of the virus in the future. Consider getting vaccinated and taking additional precautions to protect ourself from mosquito bites, especially if we live in a place where dengue is common.
When should I see my healthcare provider?
If you live in or have recently visited an area where dengue is common, contact your healthcare provider if you have any symptoms of dengue. They will give you recommendations on how to take care of yourself and when to seek additional treatment.
Is dengue deadlier than malaria?
No. While only a small percentage of those infected with either disease die from them, malaria is deadlier than dengue worldwide.
Of an estimated 400 million people worldwide who get dengue every year, about 40,000 die from it (about 0.01%). Of an estimated 271 million people worldwide who get malaria every year, about 627,000 die from it (around 0.3%).
It’s important to remember that any disease can be deadlier in some parts of the world than in others. Children in Africa are disproportionately at risk of dying of malaria, whereas people living in Asia are the most affected by dengue.