Dengue fever is a disease caused by four dengue viruses spread by the Aedes aegypti mosquito.

Once you contract one of the dengue viruses, you develop immunity to that virus for the rest of your life. However, you can still contract the other three viruses, so it’s possible to get all four dengue viruses in your lifetime. The viruses that cause dengue fever are related to those that cause yellow fever and West Nile virus infection.

The Center for Disease Control and Prevention (CDC) estimates that at least 400 million cases of dengue fever occur across the globe every year. Tropical regions are heavily affected. Areas that have the greatest risk of infection include:

  • Sub-Saharan Africa
  • Central America
  • Mexico
  • the Caribbean
  • Pacific Islands
  • India
  • South America
  • Southeast Asia
  • Southern China
  • Taiwan
  • northern parts of Australia

Very few cases occur in the United States. Most diagnosed cases occur in people who contracted the virus while traveling abroad. However, risk of infection is increasing for residents of Hawaii, Florida, and in Texas near the Mexican border.

Dengue fever is transmitted via the bite of a mosquito harboring the dengue virus. Person-to-person transmission doesn’t occur. However, a pregnant person with dengue can pass the disease to their child.

If you develop dengue fever, symptoms usually begin about 4 to 10 days after the initial infection. In many cases, symptoms will be mild. They may be mistaken for symptoms of the flu or another infection.

Young children and people who’ve never experienced infection may have a milder illness than older children and adults. Common symptoms generally last for 2 to 7 days and can include:

  • sudden, high fever (up to 106°F or 41°C)
  • severe headache
  • swollen lymph glands
  • severe joint and muscle pains
  • skin rash (appearing between 2 and 5 days after the initial fever)

Symptoms of severe dengue can include:

  • belly pain and tenderness
  • mild to severe vomiting (three times in 24 hours)
  • mild bleeding from the nose or gums
  • vomiting blood or blood in stool
  • fatigue, restlessness, or irritability

Doctors use blood tests to check for antibodies the dengue viruses or the presence of infection. A doctor may use a virological test or a serological test.

Virological test

This test directly tests for elements of the virus. This type of testing often requires specialized equipment and a staff that’s technically trained, so this type of testing may not be available in all medical facilities.

Serological test

This test detects antibodies in the blood to confirm a current or recent infection.

If you experience dengue symptoms after traveling outside the country, you should see a healthcare professional to check whether you have the virus.

There’s no medication or treatment specifically made for dengue infection.

If you believe you may have dengue, you should use over-the-counter pain relievers to reduce your fever, headache, and joint pain. However, you should avoid aspirin and ibuprofen, as they can cause more bleeding.

Your doctor will perform a medical exam, and you should rest and drink plenty of fluids. If you feel worse after the first 24 hours of illness — once your fever has gone down — you should be taken to the hospital as soon as possible to check for complications.

A small percentage of people who have dengue fever can develop a more serious form of disease known as dengue hemorrhagic fever.

Dengue hemorrhagic fever

The risk factors for developing dengue hemorrhagic fever include having antibodies to dengue virus from a previous infection and a weakened immune system.

This rare form of the disease is characterized by:

  • high fever
  • damage to the lymphatic system
  • damage to blood vessels
  • bleeding from the nose
  • bleeding under the skin
  • internal bleeding
  • bleeding from the gums
  • liver enlargement
  • circulatory system failure

The symptoms of dengue hemorrhagic fever can trigger dengue shock syndrome, which is also characterized by low blood pressure, weak pulse, cold, clammy skin, and restlessness. Dengue shock syndrome is severe and can lead to excessive bleeding and even death.

There’s now a new dengue vaccine called Dengvaxia that was approved by the Food and Drug Administration (FDA) in 2019. It’s available in some countries and requires three doses spread 6 months apart.

The best method of protection is to avoid mosquito bites and to reduce the mosquito population. When in a high risk area, you should do the following:

  • Avoid heavily populated residential areas.
  • Use mosquito repellent indoors and outdoors.
  • Wear long-sleeved shirts and pants tucked into socks.
  • Use air conditioning instead of opening windows.
  • Ensure that window and door screens are secure and that any holes are repaired.
  • Use mosquito nets if sleeping areas aren’t screened.

Reducing the mosquito population involves getting rid of mosquito breeding areas. These areas include any place where still water can collect, such as:

  • birdbaths
  • pet dishes
  • empty planters
  • flower pots
  • cans
  • any empty vessel

These areas should be checked, emptied, or changed regularly.