Singapore clear of malaria cluster but expert says system needs to be ready for another

Lynda Hong, Channel NewsAsia 27 Nov 09;

SINGAPORE: Singapore has been clear of malaria clusters for about two months. But an expert warns that because the country is so globalised, it is a matter of time before another one appears. Hence, the public health system needs to be poised to deal with it.

Dr Laurent Renia, a researcher who has three to four years of experience with Singapore's malaria situation, said that in the first 14 days of infection, the malaria parasite remains dormant in the liver.

In the recent malaria clusters here, with nearly all the 28 people infected living in foreign worker dormitories, Dr Renia said it would not have been feasible to screen all the foreign workers here.

Dr Renia, a principal investigator at Singapore Immunology Network, said: "It could have taken one month, two months, before the parasite go into the blood. They (foreign workers) could have been screened; you would have never found the parasite. (When) the parasite is released and introduces the disease, it's already too late.

"You cannot prevent it (the disease) completely. It will always happen, because you are living in the world of globalisation. You will always have people coming. You cannot do mass screening, because this is, in the operational point of view, impossible.

"What you can do is to be prepared when it happens. Public health system, be ready. So you need to have medical doctors trained to recognise a malaria parasite."

Still, hospitals say the most common way of detecting malaria is through blood tests that take up to four hours to get results.

Once the disease is detected here, the National Environment Agency or NEA is then tasked to wipe out the carrier of the malaria parasite - the Anopheles mosquito.

Unlike the Aedes mosquito that transmits dengue fever, the Anopheles mosquito exists in the outdoors and breeds in brackish water in coastal areas and seepage water.

The last big malaria outbreak in Singapore was in 2006 when there were 13 local transmissions. Singapore may still see 100 to 300 cases a year. But most of the cases were brought in by people from overseas.

Dr Renia said: "Malaria is no longer endemic in Singapore. It used to be, but it's not anymore. So if you have an outbreak, it's treated, it's contained. You move on, for the next six months, you don't have malaria. You forget (about the disease), this is human nature, you forget, till the next time. So the thing is to be prepared, and to be responsive."

The NEA has also stressed the need to stay vigilant in pre-empting any malaria outbreaks, and says it will continue to work closely with other agencies.

Since 1982, the World Health Organisation has recognised Singapore's efforts in preventing malaria from becoming endemic in Singapore.

- CNA/ir