5 Things You May Not Know About Dengue Fever

It’s dengue season.

During the warmer and rainy season of June to October, there is usually a higher transmission of dengue fever as the dengue virus multiplies quicker. With abundant rainfall, warm weather, and high humidity levels, Singapore is the ideal breeding ground for Aedes aegypti mosquitoes, which carry the dengue virus. Experts said that given the trend of extended warm weather and higher rainfall, Singapore’s annual dengue problem may get worse.

Unfortunately, 2022 is shaping up to have one of the worst outbreaks of dengue fever, with cases rising since the beginning of the year. In May 2022, the Aedes aegypti mosquito population remained high and was 11 per cent higher than in the same period in 2021. There have been more than 17,000 dengue cases in Singapore this year, as compared to 5,258 cases reported throughout last year.

If you feel unwell and suspect you may have dengue fever, consult a doctor immediately.

Here are five things you may not know about dengue fever, the vector-borne disease that is plaguing us.

1. You can get dengue more than once

There are four distinct serotypes or strains of the dengue virus, namely DENV-1, DENV-2, DENV-3, and DENV-4. This means that it is possible to get the dengue virus up to four times. According to the World Health Organization, infected individuals can develop immunity against that serotype and not the others, as cross-immunity against the other serotypes is only partial and temporary.

2. Repeat infections are more dangerous

Another point to note is that repeat dengue infections are associated with a higher risk of developing severe dengue, which can be fatal.  Examples of severe dengue include dengue-shock syndrome or dengue-haemorrhagic fever.

Read about severe dengue: https://www.who.int/news-room/fact-sheets/detail/dengue-and-severe-dengue

3. Rarer serotypes of dengue have taken a foothold

The rare DENV-3 is now widely circulating and has become the predominant serotype detected in Singapore. DENV-3 and DENV-4 have not been prevalent until five to 10 years ago. Hence, the herd immunity against these two serotypes is very low. In 2021, Singapore saw the first DENV-3 outbreak in 40 years and a 400 per cent increase in DENV-4 cases. Together, they accounted for more than half of the dengue cases sampled since February 2021. This is worrying as the low herd immunity means that more people are vulnerable to dengue infections of these serotypes.

In combination with the resurgence of the rare serotypes, the high Aedes mosquito population and work-from-home arrangements are contributing to the surge in dengue cases in Singapore.

Firstly, there are more Aedes aegypti mosquitoes detected in the community. In February 2022, the number of Aedes aegypti mosquitoes were 17 per cent higher than that of the same period in 2021.

The continued work-from-home arrangements also played a part. With a sizeable number of people staying in, there are more biting opportunities for the day-biting Aedes aegypti mosquito, resulting in greater risk of dengue transmission.

4. Global warming is affecting dengue transmission

To make matters worse, global warming is exacerbating the dengue situation, causing the Aedes mosquitoes to breed faster and the incubation period of the virus to shorten.

According to Ruklanthi de Alwis, a senior research fellow at the Duke-NUS Medical School and an expert in emerging infectious diseases, predictive modelling studies have proven that global warming will eventually expand the geographical areas in which mosquitoes thrive, as well as prolong the duration of dengue transmission seasons.

Read about ways to prevent dengue: https://www.nea.gov.sg/dengue-zika/stop-dengue-now

Given the current dengue situation, it’s important to recognise the symptoms of dengue fever for early diagnosis and treatment.

What are the symptoms of dengue fever?

Dengue takes a toll on the immune system, which may cause infected people to get sick easily. Symptoms include a sudden onset of fever for 2 to 7 days, severe headache with pain behind the eyes, joint and muscle pain, skin rashes, nausea and vomiting, and mild bleeding (e.g. nose or gum bleed, or easy bruising of the skin). The symptoms tend to appear 4 to 7 days after being bitten and range from 3 to 14 days.

If you are unsure whether you are experiencing dengue symptoms, visit your nearest My Family Clinic to take a blood test. This can determine whether you have dengue fever so that you can receive treatment as soon as possible. With our friendly, registered healthcare professional, this procedure can take less than 5 minutes. You can also use our mobile application service, HeyAlly, to take a queue number before you head to the clinic and skip the queue.

5. Some side effects may persist for up to 2 months

Dengue can cause long-term side effects such as excessive hair loss, which can last up to 1 to 2 months after acute dengue infection. Dengue-associated hair loss may be caused by direct infection or by killing hair follicle-related cells.

Read about the symptoms and warning signs of dengue: https://www.moh.gov.sg/diseases-updates/dengue

What should you do if you think you have dengue fever?

If you are diagnosed or suspected to have dengue fever, spray mosquito repellent regularly to protect those living around you.

Please seek immediate medical attention if you are facing symptoms of dengue fever. Visit your family doctor at My Family Clinic and our doctors will be happy to assist you. Blood tests and monitoring of blood platelet levels are available.

If you are returning from an area where dengue fever is widespread, please look out for symptoms of dengue fever. If you are unsure, consult your family doctor at My Family Clinic even if you do not display any symptoms.

You may video consult your doctor via AllyTele on the HeyAlly app and have your medication delivered to you.

Please note that telemedicine consultation via AllyTele is not suitable for these conditions:

  • Emergency conditions (not exhaustive)
    • Chest pain
    • Severe shortness of breath
    • Convulsions or seizures
    • Persistent bleeding or severe wounds
    • Severe abdominal pain
    • Sudden onset of numbness/weakness or slurred speech
    • Suspected fractures or dislocations presenting as severe pain, open wounds, deformity, severe bruising or swelling, loss of sensation, limb weakness etc.
  • Non-minor conditions
  • Chronic conditions which have not been previously diagnosed by a health professional
  • Any conditions deemed during telemedicine consultations to be in need of a physical consultation for further examination, diagnosis and/or treatment.

This article is brought to you by My Family Clinic and Ally.