Not impossible to wipe out Aedes mozzies in Singapore

The inability to eradicate the Aedes mosquito is certainly true for countries with large areas and if we consider the world as a whole ("Aedes mozzies can't be wiped out, say experts"; Thursday).

But Singapore is small and unique. Here are some factors to note towards achieving that goal.

•Our efforts should be directed towards eliminating the presence and formation of stagnant water. Whether mosquito larvae are found or not during an inspection is irrelevant, as these will form sooner or later.

•It is said that there are more breeding sites in private homes than in construction sites. But breeding in a construction site is usually large-scale, tantamount to breeding in, perhaps, 20 or 30 households.

•When the blockage of a public drain is reported, the remedial response is usually one-off. The same problem later recurs.

•In my experience, when obvious potential breeding sites are pointed out to outsourced inspectors, they often claim that the sites are not within their jurisdiction or area of assignment.

•Larvae usually breed in water exposed to sunlight but adult mosquitoes like to hide in shady, cool places such as bushes. Fogging may kill the adult mosquitoes but probably not the larvae.

•Mosquitoes are mostly confined to some 50m of their breeding sites, although they can be carried far away by wind.

It is not a wild dream to make Singapore essentially mosquito-free by eliminating all possible sites of stagnant water formation.

An example is my neighbourhood. For several decades, residents had been troubled by mosquitoes, which often bred in the 30 to 40 open scupper drains blocked by fallen leaves.

Eventually, after two site meetings involving several government departments, the drains were replaced with large buried pipes.

The neighbourhood has since been essentially mosquito-free, except when there is construction going on nearby.

Singapore has a small land area and every inch is accessible. Prevention is possible and it is better than cure.

Ong Siew Chey (Dr)

A version of this article appeared in the print edition of The Straits Times on September 17, 2016, with the headline 'Not impossible to wipe out Aedes mozzies in Singapore'. Print Edition | Subscribe