What is dengue fever?
Dengue fever is a mosquito-borne viral infection common in Southeast Asia, the Indian subcontinent, the Caribbean, Africa, the Americas, Australia and the Pacific islands.
Dengue fever is transmitted by the bite of a mosquito (typically the Aedes aegypti) and usually causes flu-like symptoms such as fever, pain in the muscles and general weakness.
Although most cases of dengue fever are relatively mild, even mild infections can cause painful or debilitating symptoms. In rare cases, the condition can turn into severe dengue (dengue hemorrhagic fever), which can cause acute health problems and be potentially life-threatening.
Dengue fever is in the majority of cases self-limiting, meaning it will be dealt with by the body’s immune system and disappear naturally. There is no specific treatment for cases of mild dengue fever besides supporting the body with rest and plenty of fluids. In severe cases, treatment will be more intensive, with a stay in hospital likely.
Symptoms of dengue fever
The symptoms of dengue fever usually begin to develop in between four and ten days after infection with the virus. They include:
- Fever (above 38 C or 100.4 F)
- Severe headaches
- Body aches (including muscle and joint pain)
- Pain behind the eyes
- Nausea and vomiting
- A widespread red body rash
- A loss of appetite
People with these symptoms, especially those currently in or recently returned from an area with a known danger of dengue infection, should see a medical professional as soon as possible. The symptoms of dengue fever can often be confused with flu or another virus, especially in young adults, who tend to experience a milder form of the virus.
In some cases, the virus can cause severe symptoms (also known as dengue hemorrhagic fever). Dengue hemorrhagic fever is most common in young children and people who have had the infection previously.
Symptoms of dengue hemorrhagic fever include:
- Severe abdominal (belly) pain
- Bleeding from any part of the body (most commonly the gums)
- A very high fever
- Persistent vomiting or vomiting blood
- Rapid breathing or difficulty breathing
- Skin rash
If the symptoms of dengue hemorrhagic fever are not well managed, they may develop into dengue shock syndrome. This condition may lead to severe bleeding, insufficient blood flow (shock) and even death.
Causes of dengue fever
Dengue fever is spread by mosquitoes, not from person to person. These mosquitoes are most commonly found in tropical and warm areas, and become most active at night or in the early morning.
Today, dengue fever is common in many tropical areas of the world. While everyone is at equal risk of being bitten by mosquitoes and contracting the virus, those with weakened immune systems or those who have previously been infected with the virus are most at risk of dengue hemorrhagic fever.
The female Aedes aegypti mosquito is the main carrier of the viruses that cause dengue fever. The virus is passed on via a bite from one of these mosquitos, which generally acquire the virus from the blood of an infected individual.
Aedes aegypti typically breed indoors in artificial water containers and spend the majority of their lifespan in or around the location where they emerge. However, Aedes aegypti are capable of biting and spreading the virus in any location (indoor and outdoor) at any time of the day.
Aedes aegypti are the mosquito variety most closely associated with dengue fever, however, other mosquito types have also had dengue fever outbreaks attributed to them. These mosquito types include Aedes albopictus, Aedes polynesiensis and several species of the Aedes scutellaris complex.
Diagnosing dengue fever
People with the symptoms of dengue fever should seek a medical opinion as quickly as possible. Dengue fever is diagnosed with a series of blood tests used to identify the virus itself, the immune reaction to the infection and other effects the infection may have on the body (such as reduced blood clotting).
Dengue fever treatment
If dengue fever is suspected, medical attention should be sought immediately. Doctors will generally prescribe rest and plenty of fluids to help support the body in combating the infection. If symptoms of dengue fever persist or if a person is unwell for longer than three days, urgent medical attention should be sought to avoid the risk of complications.
There is currently no effective vaccine or specific medication to treat dengue fever. Pain relievers containing acetaminophen (paracetamol) can be used to manage some of the symptoms (mainly body pain and headache), but aspirin, ibuprofen and any other anti-inflammatory medication – which can worsen bleeding – should be avoided.
Preventing dengue fever
As there is no specific treatment, prevention is key to combating dengue fever. If living or travelling in tropical areas, taking steps to avoid the reproduction of mosquitoes and avoid being bitten by mosquitoes is the most effective method of doing this.
Reducing the mosquito population by identifying and removing locations where they can breed should be the first step in dengue fever prevention. These locations include birdbaths, buckets, old tires and flower pots, or anywhere where standing water can collect.
Other effective ways to protect yourself against mosquitoes include:
- Insect repellents: To be used even when indoors and applied directly to the skin as well as to clothing. Parents should be aware that children may need repellent that has been specially approved for use on children.
- Loose and protective clothing: Mosquitos are able to bite through tight clothing, so garments should be loose and cover as much as the body as possible. Light colours are also preferable to dark.
- Mosquito net: When sleeping, a mosquito net is vital for everyone, especially children. If possible, the net should be treated with insecticide.
Dengue fever and hemorrhagic fever prognosis
Generally, dengue fever is a self-limiting infection that naturally passes within two weeks of infection. People who develop dengue hemorrhagic fever have a higher risk of life-threatening complications.
Advice for travellers
People travelling to regions where dengue fever is a risk (Southeast Asia, the Indian subcontinent, the Caribbean, Africa, the Americas, Australia and the Pacific islands) should be sure to think about prevention before they arrive.
Travellers should ensure they pack a supply of insect repellent; loose, protective clothing; and their own mosquito net to reduce the risk of being bitten. After arriving, efforts should be made to avoid locations where mosquitoes breed (such as stagnant water) and should take special care during times of the day when mosquitoes are most active (generally, at night, dusk and dawn).
If a person begins to display any signs or symptoms of dengue fever when travelling, immediate medical advice should be sought.
Dengue fever FAQs
Q: Is dengue fever contagious?
A: No. Dengue fever is not spread from person to person but via infected mosquitoes.
Q: What does the dengue fever rash look like?
A: A rash is one of the symptoms of dengue fever. Typically, it begins as a mild rash, giving the infected person a flushed appearance. As the virus develops, the rash can become more severe, turning bright red and developing lesions.
Q: When should I visit the doctor?
A: If there is any suspicion of dengue fever, you should visit a doctor immediately. A doctor will be able to evaluate your symptoms and make a proper diagnosis. If you have been diagnosed with dengue fever and the symptoms don’t go away or worsen in three days, a doctor should be seen once again to reduce the risk of complications.
Q: Which liquids should I drink?
A: People with dengue fever are encouraged to drink plenty or water, fruit juice or oral rehydration solutions. Adults should aim to drink at least three litres of water per day in order to stay hydrated.
**Q: Which liquids should infants drink? ** A: Babies under six months old should drink only breast milk or formula to avoid dehydration. Babies over six months should also be able to drink water. Doctors may recommend rehydration solutions for older children.
Q: What medicine can I take during dengue fever?
A: Acetaminophen (paracetamol) can be used to manage the body pain and headaches that typically come with dengue fever. Anti-inflammatory medication such as ibuprofen and aspirin should be avoided as they may cause complications.
Q: What virus causes dengue fever?
A: Dengue fever is caused by four closely related viruses (serotypes): DEN-1, DEN-2, DEN-3 and DEN-4. Although each of these serotypes interacts with the body in a different way, each virus causes the same symptoms to manifest.
Q: Is there a vaccine for dengue fever?
A: Twenty countries globally have licensed a dengue fever vaccine named CYD-TDV. The World Health Organization recommends its use on individuals of nine years of age or above living or travelling in countries with a seroprevalence (the extent to which the virus is present in a population, as measured in blood serum) of 70 percent or above. The vaccine does not offer total protection against dengue fever and its efficacy may differ according to age and previous exposure to the viruses that cause dengue fever. It is recommended that a doctor be consulted regarding the availability of the vaccine before travelling to an area with a confirmed dengue fever presence.
WebMD. [“Dengue Fever.”] (http://www.webmd.com/a-to-z-guides/dengue-fever-reference#1) Accessed July 6, 2017. ↩
Medical News Today. “Dengue fever: Symptoms, treatments, and prevention.” September 25, 2015. Accessed July 6, 2017. ↩
WHO. “Dengue/Severe Dengue frequently asked questions.” January 3, 2017. Accessed August 22, 2017. ↩