Dengue fever

Overview

Dengue fever is a mosquito-borne illness that occurs in tropical and subtropical areas of the world. Recently, Barbados and the countries of the Eastern Caribbean has seen a spike in cases. This in the middle of an ongoing Covid-19 pandemic is cause for concern. 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.

Researchers are working on dengue fever vaccines. For now, the best ways to prevent infection are to avoid being bitten by mosquitoes and to take steps to reduce the mosquito population.

Many people experience no signs or symptoms of a dengue infection. When symptoms do occur, they may be mistaken for other illnesses — such as the flu — and usually begin four to 10 days after you are bitten by an infected mosquito.

Dengue fever causes a high fever — 104 F (40 C) — and any of the following signs and symptoms:

• Headache
• Muscle, bone or joint pain
• Nausea
• Vomiting
• Pain behind the eyes
• Swollen glands
• Rash

Most people recover within a week or so. In some cases, symptoms worsen and can become life-threatening. This is called severe dengue, dengue hemorrhagic fever or dengue shock syndrome.

Severe dengue happens when your blood vessels become damaged and leaky. And the number of clot-forming cells (platelets) in your bloodstream drops. This can lead to shock, internal bleeding, organ failure and even death.

Warning signs of severe dengue fever — which is a life-threatening emergency — can develop quickly. The warning signs usually begin the first day or two after your fever goes away, and may include:

• Severe stomach pain
• Persistent vomiting
• Bleeding from your gums or nose
• Blood in your urine, stools or vomit
• Bleeding under the skin, which might look like bruising
• Difficult or rapid breathing
• Fatigue
• Irritability or restlessness

When to see a doctor

Severe dengue fever is a life-threatening medical emergency. Seek immediate medical attention if you have had a fever and you develop any of the warning signs. Warning signs include severe stomach pain, vomiting, difficulty breathing, or blood in your nose, gums, vomit or stools. 

Causes

Dengue fever is caused by any one of four types of dengue viruses. You can't get dengue fever from being around an infected person. Instead, dengue fever is spread through mosquito bites.

The two types of mosquitoes that most often spread the dengue viruses are common both in and around human lodgings. When a mosquito bites a person infected with a dengue virus, the virus enters the mosquito. Then, when the infected mosquito bites another person, the virus enters that person's bloodstream and causes an infection.

After you've recovered from dengue fever, you have long-term immunity to the type of virus that infected you — but not to the other three dengue fever virus types. This means you can be infected again in the future by one of the other three virus types. Your risk of developing severe dengue fever increases if you get dengue fever a second, third or fourth time.

Risk factors

You have a greater risk of developing dengue fever or a more severe form of the disease if:

• You have had dengue fever in the past. Previous infection with a dengue fever virus increases your risk of severe symptoms if you get dengue fever again.

Complications

Severe dengue fever can cause internal bleeding and organ damage. Blood pressure can drop to dangerous levels, causing shock. In some cases, severe dengue fever can lead to death.

Women who get dengue fever during pregnancy may be able to spread the virus to the baby during childbirth. Additionally, babies of women who get dengue fever during pregnancy have a higher risk of pre-term birth, low birth weight or fetal distress.

Prevention

Prevent mosquito bites

Preventing mosquito bites and controlling the mosquito population are still the main methods for preventing the spread of dengue fever.

These tips may help reduce your risk of mosquito bites:

• Stay in air-conditioned or well-screened housing. The mosquitoes that carry the dengue viruses are most active from dawn to dusk, but they can also bite at night.
• 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% 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. You can help lower mosquito populations by eliminating habitats where they lay their eggs. At least once a week, empty and clean containers that hold standing water, such as planting containers, animal dishes and flower vases. Keep standing water containers covered between cleanings.

Diagnosis

Diagnosing dengue fever can be difficult because its signs and symptoms can be easily confused with those of other diseases — such as chikungunya, Zika virus, malaria and typhoid fever.

Your doctor may draw a sample of blood to be tested in a lab for evidence of infection with one of the dengue viruses.

Treatment

No specific treatment for dengue fever exists.

While recovering from dengue fever, drink plenty of fluids. Call your doctor right away if you have any of the following signs and symptoms of dehydration:

• Decreased urination
• Few or no tears
• Dry mouth or lips
• Lethargy or confusion
• Cold or clammy extremities

The over-the-counter (OTC) drug acetaminophen (Panadol, Tylenol, others) can help reduce muscle pain and fever.

But if you have dengue fever, you should avoid other OTC pain relievers, including aspirin, ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve). These pain relievers can increase the risk of dengue fever bleeding complications.

If you have severe dengue fever, you may need:

• Supportive care in a hospital
• Intravenous (IV) fluid and electrolyte replacement
• Blood pressure monitoring
• Transfusion to replace blood loss