Dengue Fever in Singapore – “Prevention is the Only Cure”

Published 10/31/2022 in Scholar Travel Stipend

Written by Lucky Ding | 10/31/2022

“Singapore is a very safe country. You see, damaging storms will have hit other countries by the time it reaches Singapore. We are not located near any major earthquake faults. Tornados do not exist here. The only natural disaster that could possibly destroy Singapore would be dengue.”

This is how a native post-doctoral fellow described Singapore to me during my first few days of interning at the Singapore Immunology Network this past summer. This also happened to be my first introduction to one of Singapore’s primary public health concerns – dengue fever.

Now, some background on this disease. Dengue fever caused by an infection with the dengue virus, which is carried by the Aedes mosquito. Known as Aedes aegypti and Aedes albopictus, these mosquitos can be identified by the black and white stripes on their bodies. Once bitten and infected, the victim often experiences symptoms of prolonged fever, intense headaches or body aches, loss of appetite, nausea, and severe skin rashes. Complete recovery from this infection could take up to a month.1 What makes dengue so terrifying is the lack of either a vaccine or cure for infection. At best, doctors can treat the symptoms of the infection, but not the infection itself. In the worst cases, patients develop life threatening complications like Dengue Hemorrhagic Fever or Dengue Shock Syndrome, which result in bleeding into the skin and internal organs.

The dengue virus is only transmitted through the bite of an infected Aedes mosquito, but the Aedes mosquito also happens to be one of the most common types of mosquitos found in Singapore, thus making this small island nation a hotspot for the disease. Only two years ago, in 2013*, weekly dengue infection cases in Singapore were at a six-year high, and experts had feared that a possible outbreak could surpass Singapore’s worst dengue outbreak back in 2005, where 14000 people fell ill and 25 people died.2 Today, due to government action and public awareness efforts, the number of dengue cases in Singapore has been reduced and can actually be tracked online, as the Singapore National Environment Agency (NEA) daily updates the latest dengue data onto its website. 

Singapore’s government has made impressive movements in their public health approaches to containing and preventing the spread of dengue fever. “The government will send people to inspect your houses frequently and remove stagnant water,” said Andrea, a local Singaporean resident, “the gardeners will also spray your lawn with repellent regularly.” Interestingly, these large scale inspections actually only make up one small component of the NEA campaign to eliminate dengue fever in Singapore. The agency’s approach is four-fold:4

1. Preventative Surveillance and Control

2. Public Education and Community Involvement

3. Enforcement

4. Research

Under “Preventative Surveillance and Control,” the locations of active clusters of dengue cases are updated regularly on the government site so that residents can track local “hotspots.” Trained officers also carry out “search and destroy” operations, where they conduct mosquito surveillance and dengue inspection on a full time basis in Singapore. Adding another layer of ** protection, the regular home inspections previously mentioned by Andrea fit under “Enforcement,” which grants the NEA the power to enter premises to check for mosquito breeding under the Control of Vectors and Pesticides Act (CVPA).

Since there have not been any approved medications for treating dengue fever, it is best to prevent the breeding of its carrier to stop the transmission cycle. Under “Public Education and Community Involvement,” public banners replace advertisement spaces along the streets, reminding residents to remove any stagnant water that can become favorable breeding spots for the Aedes mosquito. Below is an announcement posted on the subway windows, right above the seats.

To convince the public to do their part in eliminating the risk of dengue, there is actually a movement, called the “10-minute 5 Step Mozzie Wipeout,” aimed at encouraging citizens to break the breeding cycle of the Aedes mosquito by (1) changing the water in vases and bowls, (2) removing the water from flower pot plates, (3), turning over all water storage containers, (4) covering bamboo pole holders when not in use, and (5) clearing blockages and putting insecticide in roof gutters monthly. Details, along with image depictions, can be found on the NEA website for public access.

A vaccine for dengue fever has yet to be created, but clinical research for a viable vaccine has been underway. One notable clinical trial began for the drug Celgosivir in 2012, where the efficacy and safety of the drug was assessed in patients with dengue fever. Unfortunately, the drug did not show any significant reduction in viral load or fever symptom in patients with dengue.6 The future outlook seems positive, however, with ongoing clinical research for possible vaccines and treatments. Advertisements seeking volunteers to take part in a clinical trial*** for a possible dengue vaccine were hung along the overhead handrails of each public bus for a week.

As a temporary resident of Singapore for nine weeks, I, of course, took the necessary precautions during my attachment there. I had packed one bottle of spray and one tube of lotion, each containing 35% DEET mosquito repellent. After my discussion with the local residents, I took their recommendations and bought some DEET-free mosquito repellent patches for my clothes and a can of anti-mosquito repellent for my room.

Despite my defensive efforts, I still sustained multiple mosquito bites. Luckily, I’ve yet to show any signs of dengue infection. Still, being able to experience firsthand and learn about the public health concerns from local residents certainly defined education abroad for me.

* "Life Cycle of an Aedes Mosquito." National Environment Agency. National Environment Agency. Web. 01 Sept. 2015.

**a. Chumari, Alvin. "Weekly Dengue Fever Cases Reported in Singapore Reached a Six-year High in 2013." Health Xchange. SingHealth Group, 2013. Web.

b. National Environment Agency. National Environment Agency. Web. 01 Sept. 2015. <www.dengue.gov.sg>.

c. "Operations Strategy." National Environment Agency. National Environment Agency. Web. 01 Sept. 2015.

*** a. "Prevent Aedes Mosquito Breeding." National Environment Agency. National Environment Agency, n.d. Web. 02 Sept. 2015. <http://www.dengue.gov.sg/subject.asp?id=101>.

b. Low, J. G., Sung, C., Wijaya, L., Wei, Y., Rathore, A. P. S., Watanabe, S., … Vasudevan, S. G.. "Efficacy and Safety of Celgosivir in Patients with Dengue Fever (CELADEN): A Phase 1b, Randomised, Double-blind, Placebo-controlled, Proof-of-concept Trial." The Lancet Infectious Diseases 14.8 (2014): 706-15. Web.

- Originally written in 2015 -