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Dengue Fever

Dr Karen Martin
Reviewed by Dr Karen MartinReviewed on 10.10.2024 | 5 minutes read
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Dengue fever is a mosquito-borne viral infection that poses a significant global health threat, particularly in tropical and subtropical regions and is now a major public health concern due to its widespread prevalence and potential for severe complications. In this article we look at its causes, symptoms, how it is transmitted, risk factors, complications, and how it can be prevented.

What is dengue fever?

Dengue fever is caused by the dengue virus and is spread by the Aedes mosquito. This mosquito lives in areas with tropical and near-tropical climates such as Southeast Asia, Western Pacific regions, the Caribbean, Latin America, and some parts of the US (such as Texas and Hawaii), Africa, and the Middle East. It does not live in the UK or other Western countries, although there is concern that global warming may mean the mosquito may travel to these countries in the future. However, you can become infected if you travel to a region where dengue fever is often found.

There are four types of the virus (called DEN-1, DEN-2, DEN-3, and DEN-4) that are all capable of causing the disease. The Aedes mosquitoes that pass it on to humans live in urban environments and breed in stagnant water. The transmission of the virus involves the female Aedes mosquito becoming infected after biting a person that is already infected with the virus. This infected mosquito then transmits the virus to healthy people by biting them. Unlike some other mosquito-borne diseases, dengue is not spread directly from person to person.

Who is most at risk?

Although anyone can catch dengue fever if exposed to it, certain factors can increase the risk of severe dengue occurring. These include:

  • Previous infection with dengue. People who have previously been infected with one type of the virus are at a higher risk of severe dengue if subsequently infected with a different type. As there are four types of dengue virus it’s possible to get the infection more than once.

  • Age. Children and the elderly are generally more susceptible to severe forms of the disease.

  • Immunity. Our body’s immune response is crucial. A strong immune response may help keep the severity of the infection low, while a weak or altered immune response can cause more severe symptoms.

Dengue fever during pregnancy can cause serious problems. For example, it can lead to your baby having a low birth weight. If you get dengue fever while pregnant you will need to be treated in hospital.

What are the symptoms?

The symptoms of dengue fever are similar to those of many bacterial and viral infections, and so this can make an exact diagnosis difficult without tests. As a general rule, we advise that if you have been in an area in the last two weeks where dengue fever is common and you then become ill with symptoms of a fever, it’s important to tell your doctor about it.

Symptoms range from a mild, self-limiting illness to severe and potentially life-threatening. The incubation period typically ranges from 4 to 10 days after being bitten by an infected mosquito. Common symptoms include:

  • Sudden onset of high fever that lasts up to a week
  • Severe headaches
  • Pain behind the eyes
  • Nausea and vomiting
  • Joint and muscle pain
  • Skin rash or flushing
  • Mild bleeding (such as nosebleeds or bleeding gums)

While most cases of dengue fever are self-limiting, severe dengue can lead to complications that require immediate medical attention. These complications include:

  • Dengue Hemorrhagic Fever (DHF) - characterized by bleeding, blood plasma leakage, and low platelet count, DHF can progress to shock.
  • Dengue Shock Syndrome (DSS) - a severe form of DHF, this involves a rapid drop in blood pressure, leading to shock.

Both DHF and DSS are medical emergencies that require immediate medical treatment to prevent a fatal outcome.

It is rare for anyone to die from dengue fever unless they have a severe infection, but up to 3 in 100 people with a severe infection die from dengue fever. Severe infection is more common in children. Fortunately, most people recover from dengue fever with no special treatment.

How is dengue fever treated?

There are no specific drugs used to  treat dengue fever but some people may need medical treatments such as fluids given by intravenous (IV) drip. The treatments for dengue fever are the same for adults as for children.

General recommendations for the treatment of dengue fever include:

  • Fluid replacement. Hydration is a key part of dengue fever treatment because adequate fluid intake helps manage dehydration, a common complication of the disease. Oral rehydration solutions (ORS) may be used for mild cases and you can purchase these from our shop. Severe cases of dehydration may require intravenous fluids in hospital.
  • Pain management. Acetaminophen is generally recommended for pain and fever relief. Avoid nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen and aspirin, as they can increase the risk of bleeding.
  • Rest. Adequate rest is essential to allow the body to recover and fight the infection.
  • Monitoring. For more serious cases, regular monitoring of vital signs, blood pressure, and platelet count is important to detect any signs of complications. Severe cases or cases with warning signs should be monitored in a hospital setting. Warning signs may include persistent vomiting, abdominal pain, mucosal bleeding, lethargy, restlessness, and a rapid decrease in the platelet count.

Preventing dengue fever

If you are visiting an area where dengue is endemic while pregnant, it is especially important to take all the precautions you possibly can against mosquito bites. The mosquitoes that carry dengue fever are the same ones that carry Zika and an infection called chikungunya. Ways to reduce your risk of catching dengue fever include:

  • Using a mosquito repellent. Apply this to exposed skin, especially during peak mosquito activity times (dawn and dusk). Use repellents containing DEET, picaridin, or oil of lemon eucalyptus.
  • Wearing protective clothing such as long-sleeved shirts, long pants, socks, and shoes to cover exposed skin.
  • Avoiding peak mosquito activity by trying to stay indoors during peak mosquito activity times, especially early morning and late afternoon.
  • Using mosquito nets or screens on windows and doors, especially if you live in an area with a high incidence of dengue.
  • Removing any standing water around your home to eliminate mosquito breeding sites - mosquitoes lay eggs in stagnant water. Regularly empty and clean containers that can collect and hold water, such as flowerpots, bird baths, and gutters.
  • Installing mosquito screens on your windows and doors to prevent mosquitoes from entering your home.

If travelling to areas with a high risk of dengue, take extra precautions, such as using bed nets and applying mosquito repellent.

In some regions, a dengue vaccine may be available. Check with your doctor to determine if vaccination is recommended where you are.

Remember - it's essential to be proactive in preventing dengue, as there is no specific antiviral treatment widely available for this infection. If you suspect you may have dengue fever, seek medical attention promptly for proper diagnosis and management of your symptoms.

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Dr Karen Martin
Reviewed by Dr Karen Martin
Reviewed on 10.10.2024
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