New computer model predicts dengue outbreaks

SINGAPORE - The fight against mozzies has gone high-tech.

The National Environment Agency (NEA) has added to its arsenal a sophisticated computer model that predicts dengue outbreaks.

Scientific research - some of it done in Singapore - could also yield the world's first vaccine and cure for dengue in the next few years.

Associate Professor Ng Lee Ching, director of the NEA's Environmental Health Institute, said the predictive model is an example of how the agency is using technology to conduct surveillance of the dengue virus itself.

She introduced the model, called a temporal risk map, at the first Singapore International Conference on Dengue and Emerging Diseases last week.

Prof Ng said being able to predict dengue patterns for the year ahead is "very useful for both operations and policymakers".

For instance, it helps with allocating resources and chemicals.

The temporal risk map makes predictions based on historical data on factors like changes in the climate, said Prof Ng, adding that the model still needs some refining before being put to the test.

The agency is already using a spatial risk map which predicts high-risk areas.

This allows officers to zoom in on, for instance, areas with large mosquito populations but where residents have not yet been exposed to the disease.

"If you don't have all this intelligence, you're going to just sweep across... You won't have much impact," said Prof Ng.

What she calls "virus surveillance" has already helped to prevent a potential outbreak this year.

Past data suggests an outbreak is usually imminent after the dominant type of dengue changes.

This occurred during the 2005 and 2007 epidemics.

There are four types of dengue and the Den-2 virus has been predominant here since 2007.

But early this year, the NEA detected that the Den-1 virus was catching up with Den-2.

It alerted its field officers and other government agencies, and the outbreak was suppressed, said Prof Ng.

Promising research has also been done on treating and preventing dengue, said Professor Duane Gubler of the Duke-NUS Graduate Medical School.

He estimates that the world could see the first vaccine and anti-viral treatment for dengue in the next five years.

Staff from Duke-NUS are involved in research on the drug Celgosivir, which could be the first dengue cure, as well as on a potential vaccine by research firm Inviragen.

However, both professors emphasised that the fight against dengue is multi-pronged.

For instance, the NEA still relies on the time-tested method of going door to door to control the disease-spreading Aedes mosquito. Community participation, said Prof Ng, is also the "anchor" of ensuring that mosquitoes do not have places to breed.

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