Dengue fever cases on the rise again

Photo above: A drain clogged with dead leaves near Block 220 Hougang Street 21. This is a potential mosquito breeding area along with the usual suspects such as roof gutters, uncovered buckets and plant pot plates.

SINGAPORE - After a short breathing space during the Chinese New Year, dengue fever cases are up again, with 297 people infected last week and another 162 since Sunday.

In the week beginning Feb 10, the number of people diagnosed with dengue fell to 247, from a high of 322 the previous week.

Dr Koh Hau Tek, medical director of the Parkway Shenton chain of clinics, said a possible reason for the fall in numbers that week could be foreign workers going home for the holiday season, as well as Singaporeans taking advantage of the four-day weekend break to travel.

Another reason, he said, could be "the belief that visits to medical facilities during the Lunar New Year period do not bode well for the new year".

So people who are not very sick might prefer to self-medicate.

A worrying trend that has emerged is that seven of the 24 active clusters are caused by Den-1 and Den-3 viral strains.

There are four dengue strains. Since 2007, the dominant strain has been Den-2, so the population might have little immunity against other strains. Furthermore, someone who has been infected before, tends to be more sick when infected by a different strain.

Three of the four clusters in Hougang, totalling 79 people, are caused by the Den-3 virus. The biggest, with more than 60 people infected, is in Street 51, Street 52 and Avenue 6.

Den-1 is responsible for three other clusters with 12 people infected.

A spokesman for the National Environment Agency said: "NEA and members of the Inter-Agency Dengue Task Force are stepping up inspections to search and destroy mosquito breeding in premises as well as outdoor areas in these estates."

While dengue is endemic in Singapore, it is unusual to have such a high number of infections at this time of the year, which is traditionally the low season.

The peak tends to be in the hotter months in the middle of the year. This year has been an exception, with the number of infections well above the epidemic level of 165 a week, for seven out of the eight weeks.

More than 2,000 people have been sick with dengue this year, compared to fewer than 600 over the same period last year.

Symptoms of dengue fever include a high fever, severe headache, joint and muscular ache and a red rash. In severe cases, the person could bleed from the nose and gums.

Anyone with such symptoms is encouraged to see a doctor as soon as possible.

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