We all dread the mention of dengue. It is a viral infection caused by the bite of an infected mosquito. It is only the Aedes type of mosquitoes that transmits the virus, and only a fraction of the mosquitoes are infected. The infection causes flu-like symptoms such as high fever, headaches typically behind the eyes, muscle and joint pain, nausea and stomach ache.
The number of dengue cases globally is on the rise. About 390 million people are infected by dengue every year worldwide. But of these, only 25% – or 100 million – may develop symptoms according to the World Health Organisation.
According to a study conducted by Dr Katja Fink of A*STAR with blood samples from healthy student volunteers from the National University of Singapore, about 80% who have been infected by dengue based on their antibody titers did say that they never had a dengue infection when asked .
What are the reasons that some people’s bodies can fight off the virus while others don’t? How can you prepare your body to fight against the virus?
The first step to helping yourself is to know more about dengue:
1. Dengue mosquitoes are a lazy lot
Aedes mosquitoes are very lazy, explains Dr Fink. They don’t fly very far. “The radius of their reach is probably only 200 meters,” she says. This means that dengue outbreaks always occur in clusters. One infected mosquito can start an infection cluster by infecting one person and if the chain-reaction between mosquito-human-mosquito is not interrupted the infection will spread.
The best way to safeguard yourself and your family is to make sure that these mosquitoes don’t breed in your backyard or in potted plants, and importantly, not inside the house. Aedes mosquitoes like to stay indoors as well as in dark corners.
2. You can be infected several times by dengue
With many known viruses, the first infection will protect you against a reinfection. This is the principle of the vaccination: mimic the infection to protect later against the real microbe. Dengue is more tricky since four closely related viruses cause dengue infections. Each of these viruses are genetically close (60 to 75% of similarity) but different enough to escape the antibodies in our blood made against one serotype. So if you are infected first by a type of virus and infected later by a different type, you are not fully protected… even worse, the second infection could be more severe! Scientists are trying to understand this phenomenon and hypothesis that antibodies produced during the first infection, against a precise type of dengue, could become deleterious during a second infection with another type of dengue. Finally, people who don’t show any symptoms could produce very good antibodies able to recognise all types of dengue and neutralise all of them.
“If you develop symptoms including high fever that persists for more than 24 hours, it is best to see a GP or a Polyclinic. Doctors are trained to identify the symptoms and monitor the course of the disease. They will also refer the patients to hospitals if the signs show that the condition is worsening” says Dr. Fink.
3. Deal with stress to deal with dengue
While it is important to be prepared with mosquito repellents and patches all day, Dr. Fink advises to be extra careful during dawn and dusk. That is the time when dengue mosquitoes are most active.
By now we know that not everyone who is bitten by a dengue mosquito shows signs of an infection. This is because our body’s natural immunity may be protecting us. So, how do you build your body’s immunity?
“To improve your immune response, follow an active lifestyle with healthy eating habits. In my opinion a work-life balance along with an active exercise routine can dramatically improve a body’s immunity,” Dr Fink advises. “There is no guarantee, however, everyone can get dengue. But it certainly helps to be in good health to recover faster.”
Opportunity to visit the dengue lab and learn more about this disease
During the one-north Festival, the dengue lab in SIgN was part of a lab tour. Dr Angeline Rouers, a Research Fellow in Dr Fink’s lab, showed how our immune system fights dengue infection. Interactive aids was used to tell the story of dengue viruses and also explain how antibodies, that are part of our immune system, function.
Several techniques such as ELISA, ELISpot and Focus Assay, that are used to analyse antibodies from dengue-infected patients was showcased so guests could observe scientists performing these techniques live. Look out for lab tours at the next one-north festival!
Dr Katja Fink
Katja Fink has studied how patients’ immune systems react to dengue infection for more than ten years, after moving to Singapore from Switzerland. Together with her team at the Agency for Science, Technology and Research (A*STAR), she is working on immunotherapies for dengue, including vaccines and antibodies. She also teaches at Nanyang Technological University as an Adjunct Assistant Professor.
Dr Angeline Rouers
Angeline Rouers is research fellow at the Singapore Immunology Network (SIgN), A*STAR where she works on B cell and antibody responses during dengue-infection. She obtained her PhD in 2016 in France where she studied HIV-infection. Her research interests include antibody responses and vaccine development. She is also president of Pint of Science Singapore (pintofscience.com) and author of the scientific French blog Chercheur and Co (www.chercheurandco.fr).