Dengue fever: symptoms, treatments, and prevention

Dengue fever: symptoms, treatments, and prevention

Dengue fever, also known as breakbone fever is a mosquito-borne infection that causes a severe flu-like illness. Four different viruses can cause dengue fever, all of which are spread by a particular type of mosquito.

Dengue fever can vary from mild to severe; severe forms include dengue shock syndrome and dengue hemorrhagic fever (DHF). Patients who develop the most serious forms of dengue fever usually need to be hospitalized.

There are currently no vaccines for dengue fever. The best way to prevent the disease is to avoid being bitten by mosquitoes altogether. Although there is no precise treatment for dengue, it is treatable if caught before developing into dengue shock syndrome or dengue hemorrhagic fever.

A study published in Nature (April 2013 issue) showed that there are approximately 390 million people worldwide infected with the dengue virus each year, over three times as many as the World Health Organization's estimate of up to 100 million.

Here are some key points about dengue fever. More detail and supporting information is in the main article.

  • Dengue is transmitted between people by the mosquitoes Aedes aegypti and Aedes albopictus, which are found throughout the world.
  • Around 2.5 billion people, or 40 percent of the world's population, live in areas where there is a risk of dengue transmission.
  • Dengue is endemic in at least 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean.
  • Symptoms of infection usually begin 4-7 days after the mosquito bite and typically last 3-10 days.
  • If a clinical diagnosis is made early, DHF can be effectively treated using fluid replacement therapy.

Dengue fever is commonly spread by the Aedes aegypti mosquito, and more rarely by the Aedes albopictus mosquito.

Where is dengue fever most common?

Dengue fever is most commonly found in subtropical and tropical areas, such as Central and South America, parts of Africa, parts of Asia, the Caribbean, and the Pacific.

Most cases of dengue among United States citizens occur in those inhabitants of Puerto Rico, the US Virgin Islands, Samoa, and Guam, which are endemic for the virus.

The high-risk regions for catching dengue fever are:

  • Central America - Costa Rica, Guatemala, Honduras, Mexico, Panama, Puerto Rico.
  • South America - northern Argentina, Bolivia, Brazil, Guyana, Paraguay, Venezuela.
  • The Caribbean - Barbados, Dominican Republic, Jamaica, Suriname, Trinidad.
  • Tropical Asia - northern Australia, the entirety of Bangladesh, Cambodia, India, Indonesia, Laos, Malaysia, Micronesia, Pakistan, Paraguay, Philippines, Samoa, Singapore, Sri Lanka, Taiwan, Thailand, Vietnam, and increasingly in southern China.

Dengue is just as prevalent in urban areas as it is in rural areas (unlike malaria). However, researchers from the Nagasaki Institute of Tropical Medicine in Japan reported in PLoS Medicine (August 2011 issue) that people living in rural areas have a higher risk of dengue virus infection than city dwellers.

According to the World Health Organization (WHO):

  • Approximately 2.5 billion people, or two-fifths of the world's population, are now at risk from dengue.
  • The disease is now endemic in over 100 countries.
  • Dengue hemorrhagic fever is a leading cause of serious illness and death among children in some Asian countries.
  • In 2007, there were over 890,000 reported cases of dengue in the Americas, of which 26,000 cases were DHF.
  • Dengue infection rates among people who have not been previously exposed to the virus are commonly 40-50 percent during epidemics, but may sometimes reach 80-90 percent.
  • Approximately 500,000 people with DHF are hospitalized each year, of which many are children. About 2.5 percent of these patients die.
  • DHF fatality reads may exceed 20 percent if untreated. If there is access to medical care with doctors trained in treating DHF, the death rate may be less than 1 percent.

Symptoms of dengue fever

The symptoms of dengue fever. Image created by Mikael Häggström.

Symptoms of dengue fever vary depending on the severity of the disease.

Mild dengue fever

Symptoms can appear up to 7 days after the mosquito carrying the virus bites and usually disappear after a week. This form of the disease hardly ever results in serious or fatal complications.

The symptoms of mild dengue fever are:

  • aching muscles and joints
  • body rash that can disappear and then reappear
  • high fever
  • intense headache
  • pain behind the eyes
  • vomiting and feeling nauseous

Dengue hemorrhagic fever (DHF)

Symptoms during onset may be mild, but gradually worsen after a number of days. DHF can result in death if not treated in time. Mild dengue fever symptoms may occur in DHF, as well as the ones listed below:

  • bleeding from mouth/gums
  • nosebleeds
  • clammy skin
  • considerably damaged lymph and blood vessels
  • internal bleeding, which can result in black vomit and feces (stools)
  • lower number of platelets in blood - these are the cells that help clot the blood
  • sensitive stomach
  • small blood spots under your skin
  • weak pulse

Dengue shock syndrome

This is the worst form of dengue and can also result in death; mild dengue fever symptoms may appear, but others likely to appear are:

  • intense stomach pain
  • disorientation
  • sudden hypotension (fast drop in blood pressure)
  • heavy bleeding
  • regular vomiting
  • blood vessels leaking fluid
  • death

Causes of dengue fever

There are four dengue viruses (DENV) that cause dengue fever, all of which are spread by a species of mosquito known as the Aedes aegypti mosquito, and more rarely by the Aedes albopictus mosquito.

Aedes aegypti originated in Africa, but nowadays is found in all the tropical areas around the world; it prospers in and close to areas of human population.

The virus is transmitted from an infected mosquito to a human. A mosquito bites a person who is infected with the dengue virus; the virus is then passed on when someone else is bitten by the mosquito.

If you have suffered from dengue fever previously it is still possible to contract it again. If you were infected again and became ill, there is a greater risk of developing a harsher form of the disease.

Diagnosis of dengue fever

The signs and symptoms of dengue fever are similar to some other diseases, such as typhoid fever and malaria, which can sometimes complicate the chances of a prompt and accurate diagnosis.

In order for a doctor to properly diagnose dengue fever they will:

  1. Assess the symptoms - the doctor will take into account all of the symptoms. Some tests may be ordered to confirm whether it is a dengue infection.
  2. Blood sample - this sample can be tested in a laboratory to find signs of the dengue virus. If the dengue virus is detected, diagnosis is straightforward, if this fails, there are other blood tests.
  3. Assess medical history - the doctor will need to know about the patient's travel history and medical history, especially if it involves mosquito exposure.

Treatment and prevention of dengue fever

Dengue is a virus, so there is no specific treatment or cure. However, there are things a patient or doctor can do to help, depending on the severity of the disease. For milder forms of dengue fever the treatment methods are:

  • Prevent dehydration - high fever and vomiting can dehydrate the body. Make sure to drink clean (ideally bottled) water rather than tap water. Rehydration salts can also help replace fluids and minerals.
  • Painkillers - this can help lower fever and ease pain. As some NSAIDs (non-steroidal anti-inflammatory drugs), such as aspirin or ibuprofen can increase the risk of internal bleeding, patients are advised to use Tylenol (paracetamol) instead.

The following treatment options are designed for the more severe forms of dengue fever:

  • Intravenous fluid supplementation (IV drip) - in some cases of dengue the patient is unable to take fluids orally and will need to receive an IV drip.
  • Blood transfusion - a blood transfusion may be recommended for patients with severe dehydration.
  • Hospital care - it is important to be treated by doctors, this way the individual can be properly monitored in case symptoms worsen.
  • Prevention of dengue fever

    At present, there is no dengue vaccine. The best method of prevention is to avoid being bitten by mosquitoes. Anyone who lives in or travel to an area where dengue fever exists, there a number of ways to avoid being bitten.


    The chances of being bitten are significantly reduced if as little skin as possible is exposed. When in an area with mosquitoes, wear long pants, long sleeved shirts, and socks. For further protection, tuck pant legs into shoes or socks and wear a hat.

    Mosquito repellents

    The best way to avoid dengue is to avoid being bitten.

    Use a repellent with at least 10 percent concentration of DEET (diethyltoluamide), a higher concentration is necessary for longer lengths of exposure. Avoid using DEET on young children. Mosquito traps and nets.

    Studies have shown that the risk of being bitten by mosquitoes is reduced if by using a mosquito net while sleeping. Untreated nets are less effective because the mosquito can bite through the net if the person is standing next to it.

    Nets that have been treated with insecticide are much more protective.

    Not only does the insecticide kill the mosquito and other insects, it is also a repellent - therefore fewer mosquitoes are likely to enter the room.


    Avoid wearing heavily scented soaps and perfumes as these are known to attract mosquitos.


    Use structural barriers, such as window screens or netting.


    When camping, treat clothes, shoes, and camping gear with permethrin. Clothes are available that have been pre-treated with permethrin. Try to avoid being outside at dawn, dusk, and early evening.

    Stagnant water

    The Aedes mosquito prefers to breed in clean, stagnant water. It is important to frequently check and remove stagnant water in your home/premises. Here are some tips for this:

    • Turn buckets and watering cans over; store them under shelter so water cannot accumulate in them.
    • Remove the water from plant pot plates. To remove mosquito eggs, clean and scrub them thoroughly.
    • Loosen soil from potted plants. This will prevent puddles from developing on the surface of hard soil.
    • Make sure scupper drains are not blocked; do not place potted plants and other objects over the scupper drains.
    • Gully traps that are rarely used should be covered; replace gully traps with non-perforated ones, and install anti-mosquito valves.
    • Do not place receptacles under or on top of any air-conditioning unit.
    • Flower vases - change the water every other day and scrub the inside of the vase thoroughly and rinse it out.
    • Leaves - make sure leaves are not blocking anything that may result in the accumulation of puddles or stagnant water.

Dengue fever, Symptoms and its Protection (Video Medical And Professional 2020).

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