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Understanding Dengue Fever
Dengue fever is a disease caused by the dengue virus which is transmitted to humans via the bite of an infective mosquito. There are four different serotypes of dengue virus (DENV1-4) circulating in the world, including Singapore. Hence, individuals can be infected with dengue up to four times. First-time dengue infections can be severe, especially among the elderly and those with pre-existing medical conditions, and repeat dengue infections have been associated with a higher occurrence of severe dengue.
Dengue haemorrhagic fever and dengue shock syndrome can be fatal. Together with the National Environment Agency (NEA), we track all dengue-related deaths in Singapore which are reported quarterly.
How dengue is transmitted
Dengue fever is transmitted to humans via the bite of an infective Aedes mosquito. A mosquito becomes infected after it takes a blood meal from a dengue-infected person. It becomes infective after an extrinsic incubation period of 8 to 12 days. The mosquito then remains infective for the rest of its lifespan. When a person is bitten by an infective mosquito, they may develop symptoms after an intrinsic incubation period of 4 to 7 days (ranges from 3 to 14 days). Notably, up to 75% of dengue infections are asymptomatic. Dengue fever does not spread from person to person.
Symptoms of dengue fever
Sudden onset of fever for 2-7 days
Severe headache with pain behind the eyes
Joint and muscle pain
Nausea and vomiting
Mild bleeding (e.g. nose or gum bleed, or easy bruising of the
Symptoms usually appear 4-7 days after being bitten (ranges from 3-14 days).
Risks of dengue fever
In rare cases, dengue fever may progress to dengue hemorrhagic fever or dengue shock syndrome. These are severe forms of the infection that can result in death.
Symptoms of severe dengue may include:
More severe bleeding problems (gum bleeding, nose bleeding, bleeding into the skin and internal organs, black/tarry stool)
Plasma leakage (abdominal pain, persistent vomiting)
These usually develop after the start of recovery from the initial infection.
Protecting against dengue
You can prevent mosquito bites by applying insect repellent, wearing long, covered clothing and sleeping under mosquito nets or in rooms with wire-mesh screens or air-conditioned rooms to keep out mosquitoes.
Preventing the spread of dengue is also about maintaining vigilance in your environment. The Aedes mosquito has a distinctive black and white striped body, and prefers to breed in clean, stagnant water. By frequently checking and removing stagnant water from your home, you can help to prevent the spread of dengue fever. For more advice on preventing Aedes mosquito breeding, you can visit the National Environment Agency website.
The Health Sciences Authority (HSA) has approved a dengue vaccine, which is available for individuals aged 12-45 years old. You can consult your doctor to find out if you are suitable for the dengue vaccine.
What to do if you think you have dengue fever
If you think you have dengue fever, seek medical attention immediately.
Treatment for dengue fever
There is no specific treatment for dengue fever, or its more serious forms, dengue haemorrhagic fever and dengue shock syndrome. Treatment for dengue is supportive.
In more severe cases, you may be hospitalised for aggressive emergency treatment, including fluid and electrolyte replacement, and/or blood transfusions.