Unless the trend of infections is halted, the number of sick people could hit record levels in three years' time.

The bulk of the money is going into seeking out and destroying mosquito breeding sites, and mounting a targeted war against mosquitoes in areas where two or more people fall ill.

The bad news: The mosquito seems to be winning so far.

The number of infections from January to last Saturday is already 60 per cent higher than in the same period last year.

The severe, flu-like illness is also manifesting in a more deadly form called dengue haemorrhagic fever, for which no vaccine or cure is available. Victims are treated only for the symptoms - high fever, body aches and nausea.

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Twenty people died from it last year.

Dr Ng Lee Ching, who heads the Environmental Health Institute (EHI) of the National Environment Agency (NEA), said: 'If nothing is done to stop the spread, the number of cases will increase very significantly.'

The experts are also concerned because the Aedes aegypti mosquito, which spreads the disease, seems to be spreading to areas of Singapore where it previously was not found.

From 2004 to last year, for example, it became predominant in Bukit Batok, an area where it had not previously been a significant problem.

More than 5,000 homeowners were fined last year for breeding mosquitoes. The fine has been doubled to $200 from last Tuesday.

Construction sites found breeding mosquitoes are fined $2,000 the first time and last year, 44 were made to stop work and get cleaned up. This year, three have been ordered to stop work for anti-mosquito action.

Still, the number of infections has kept rising. Said Dr Ng: 'We cannot understand why the numbers are climbing.'

Dengue outbreaks happen in cycles which peak every six to seven years. During the last peak in 2005, 14,209 people were infected and 25 died.

That year's total was almost three times the previous peak of 5,258 in 1998.

The dengue numbers have been rising even during the low years. The last low point, in 2006, saw more than 3,000 falling sick - more than three times the number infected in previous low years.

Last year, which marked the start of the current upswing, more than 8,800 people were taken ill - the third highest number ever.

Dr Ng put last year's large number down to a change in the dominant virus - from Den 1 to Den 2 - that was circulating. People had lower immunity against Den 2 than Den 1.

Last year, when three people in Tampines fell ill with the rare Den 3 strain of dengue fever, the EHI leapt into action to prevent the strain from spreading.

As part of the war on dengue this year, new and faster test kits will be made available at doctors' clinics.

Speedier discovery of infected patients will let the anti-dengue teams descend on the affected areas to stop the spread.

salma@sph.com.sg

CHEAPER, FASTER DENGUE TEST KITS ON THE WAY: SINGAPORE