Understanding Dengue Fever
Dengue fever is a mosquito-borne tropical disease caused by the dengue virus which is transmitted to humans via the bite of an infected Aedes mosquito. It can be caused by 4 different strains of the same virus (DENV-1, DENV-2, DENV-3 and DENV-4). If you have been infected from one strain, you can get infected again from the remaining 3 strains. Hence, individuals can be infected with dengue fever up to four times.
Recovery from dengue infection is believed to provide lifelong immunity against that strain but not against the other strains. First-time dengue infections can be severe, especially among individuals with weakened immune systems. Repeated dengue infections increase the risk of developing severe dengue.
Dengue fever is widespread throughout the tropics. In Singapore, the Ministry of Health has reported 20 deaths, and the cumulative number of dengue cases to date this year stands at over 22,400. Our neighbourhoods are categorized as green, yellow and red zones to indicate the increasing risk of dengue fever in that vicinity respectively. Currently, there are close to 400 dengue clusters in Singapore.
How does Dengue Fever spread?
Mosquito-to-human Transmission
The dengue virus is transmitted to humans through the bites of infected female Aedes mosquitoes.
Human-to-mosquito Transmission
Humans carrying the dengue virus can infect mosquitoes. A mosquito becomes infected when it takes a blood meal from a dengue-infected person. After an incubation period of 8 to 12 days, the mosquito becomes infective and will remain infective throughout its lifespan.
Dengue fever is not contagious and does not spread directly from person to person.
Symptoms of Dengue Fever
A person bitten by an infected Aedes mosquito may develop symptoms after approximately 3 to 14 days.
Common symptoms associated are:
- Fever of sudden onset, lasting for 1-7 days
- Muscle and joint pains
- Severe headache
- Pain behind the eyes
- Skin rashes
- Bleeding eg from the gum and nose, and easy bruising
- Nausea and vomiting
The main risk of dengue fever is the progression to dengue hemorrhagic fever or dengue shock syndrome which can result in death in rare cases. This occurs about 3 to 7 days after the first onset of symptoms with worsening symptoms. Warning signs of severe dengue include:
- More pronounced bleeding problems (bleeding from the nose and gums, into the skin and internal organs, black coloured stool)
- Persistent vomiting
- Severe abdominal pain
How is Dengue Fever treated?
There is no specific medication or antibiotic to treat dengue fever. Treatment is supportive and directed towards the relief of symptoms. Medications can be taken to control the symptoms of muscle pain and fever. In addition, having ample rest and plenty of fluids is key to avoid dehydration from vomiting and high fever.
In more severe cases, there may be a need to be hospitalized for careful monitoring and treatment that includes fluid and electrolyte replacement and/or blood transfusions.
How to protect against Dengue Fever?
The best protection is to avoid getting bitten by mosquitoes. This can be done by:
- Applying insect repellent regularly
- Wearing long-sleeved tops and long pants of light colours
- Sleeping under mosquito nets installing wire-mesh screens on windows, or in air-conditioned rooms to keep mosquitoes out
- Spraying insecticide in dark corners around the house
Aedes mosquitoes prefer to breed in clean, stagnant water easily found in our homes. You can prevent them from breeding by:
- Loosening hardened soil
- Turning over pails
- Tipping vases
- Flipping flowerpot plates
- Clearing the roof gutter and placing BTI insecticide
More information can be found in the National Environment Agency website.
Is there a vaccination for Dengue Fever?
Yes, Dengvaxia® is a vaccine used to help protect against dengue disease in individuals aged 12 – 45 years, and who have had prior dengue infection.
It is not recommended for those who have NOT had previous infection as evidence shows a longer term risk of more severe disease upon infection in such individuals following vaccination.
You may book an appointment with us for vaccinations or consult our doctor to find out if you are suitable for the dengue vaccine.
What should you do if you suspect you have Dengue Fever?
Please seek immediate medical attention if you think you have dengue fever. Blood tests to screen for dengue and monitoring of blood platelet levels are available to aid the diagnosis and management of dengue fever.
If you are returning from an area where dengue fever is prevalent, you should also be vigilant and monitor for symptoms of dengue fever. If in doubt, consult a doctor even though you may not display any symptoms. Our doctors at Minmed Clinics will be happy to assist you.
You can now Teleconsult via our Minmed Connect App. Download the app and find out more about our Teleconsult service.
Dr Lisa Chen
M.B.B.S. (Singapore) Grad. | Dip. Occupational Medicine
Dr Lisa Chen is a deeply passionate family physician and designated workplace doctor with an endearing commitment to the successful attainment of health and wellness at individual, workplace and community levels. Having worked widely with family practice clinics and major medical disciplines, she is thoroughly committed to the promotion and sustenance of health and quality of life for everyone.
