Let wildlife play a role in killing mosquitoes

Straits Times Forum 19 Jun 13;

I THANK Mr Loh Kwek Leong for his letter ("Redefining dengue clusters"; last Friday).

He made some valid points but I would like to complement his knowledge with some comments.

First, it is impossible to entirely eliminate mosquito breeding in tropical Singapore.

Singapore should attempt to eliminate artificial mosquito breeding, which happens in clean water in homes.

Therefore, there is a need to create areas for the natural breeding of frogs, fish, fauna and insects that eliminate the pests naturally.

Dragonfly larvae destroys mosquito larvae - especially that of the Aedes mosquito - and the focus should be on creating environments where these natural predators can thrive, rather than fogging them all to death.

Many people do not know that the most prevalent way that mosquitoes breed is in curled-up leaves.

While Mr Loh suggests that the National Environment Agency (NEA) increase its checks on rooftop gutters, such an exercise will be rendered fruitless considering the impossibility of checking every single curled-up leaf in Singapore.

Actually, many farmers and workers in Lim Chu Kang do live on their farms but we take necessary precautions such as sleeping under mosquito nets and applying repellent when necessary.

Farmers do not fog their farms so there is a good balance of nature and wildlife that kills off mosquitoes naturally. However, we do create a small "smoke" screen to chase mosquitoes away.

I applaud the NEA for its valiant effort so far but I think a different approach needs to be taken, instead of wasting time and energy with excessive fines and campaigns.

As infected people also become carriers of dengue fever, the authorities should consider quarantine, as was done during the severe acute respiratory syndrome (Sars) outbreak.

As president of the Kranji Countryside Association, which has 40 member farms, I assure the people that we have a very serious "Mosquito Watch" working closely together with the NEA in the Kranji countryside so that our visitors are safe.

Ivy Singh-Lim (Mrs)
President
Kranji Countryside Association

Redefine dengue clusters
Straits Times Forum 14 Jun 13;

WHILE I am glad that the National Environment Agency (NEA) is stepping up its efforts to combat dengue fever ("Dengue cases expected to surpass 1,000 a week"; Wednesday), I am more concerned that it may be overlooking some of the Aedes mosquito's breeding grounds.

Minister for the Environment and Water Resources Vivian Balakrishnan said that the number of dengue infections is worrying because Singapore is just entering the dengue season.

If dengue fever is seasonal, wouldn't that suggest that outdoor breeding is the more likely cause?

I suggest that the NEA concentrate its efforts on outdoor breeding sites.

Scientific studies have found that the Aedes mosquito is just as likely to breed in tree holes as in people's homes.

Roof gutters in private houses and the rooftops of HDB blocks could also be potential breeding sites for the Aedes mosquito.

How often does the NEA conduct checks on these areas?

The NEA defines a dengue cluster as one where two or more dengue cases occur within 14 days, and the homes of the dengue victims are within 150m of each other.

But this assumes that the victims were bitten at home or in their neighbourhood.

As the Aedes mosquito is known to bite at any time of the day, it could be just as likely that the victims were bitten at work or at school.

A better definition for a dengue cluster would be where two or more breeding sites are found within 150m of each other.

This information would be more useful as Singaporeans would then know where they should take extra care.

For instance, I visited several farms at Lim Chu Kang last week and saw swarms of mosquitoes at the back of the farms where the drains are located. But the NEA's website did not list Lim Chu Kang as a dengue cluster.

One reason for this could be because most of the people who work on the farms do not live there.

Dengue fever has plagued the country for many years and this year, it has become a full-blown epidemic that threatens the lives of all Singaporeans.

There is an urgent need to re-examine the methods currently being used to combat it.

Loh Kwek Leong