An Insight into the dengue problem

Tuesday, 2 March 2010

An Insight into the dengue problem

By M. Vivekananda
Subang Jaya

After being warded for dengue fever myself at Sime Darby Medical Centre (formerly known as SJMC) from 1st to 4th January 2010 and still convalescing, by chance I stumbled across what could be the main cause of the dengue outbreak which is due to the drains in front our residential houses.

When MPSJ conducts fogging operations, they only concentrate on the front and sometimes the back portions of the residential houses and generally do not completely fog all portions of the drains especially the areas covered by the driveway which cannot be reached by the fogging hoses.

There are extensive covered portions (for the driveway) in the front drains which can provide breeding grounds for the Aedes mosquitoes. In addition, construction renovation works of houses in the neighbourhood results in debris and soil sediments flowing into the drains and these together with leaves and twigs, etc. result in puddles of water trapped in the drains. When there is heavy rain, then the rapidly flowing water causes the Aedes mosquito larvae to be removed. But when there is no heavy rain for some days, the trapped puddles of water as mentioned can result in the formation of mini-reservoirs for the breeding of the Aedes mosquitoes. In Subang Jaya, there is possibly an infinite number of such mini-reservoirs, in the drains in front of residential houses, which act as breeding grounds for the mosquitoes.

Do the officers from the Health Department of MPSJ test the water in blocked drains for the presence of larvae of the Aedes mosquito?

Other possible places where the mosquitoes can breed are in the roof gutters and in houses where portions of the roof are flat; the flat concrete roofs where the down-pipes that are clogged by leaves can result in rain water being trapped and become breeding ground for the mosquitoes.

The Aedes mosquitoes need only 7 days to develop from eggs to adults. To overcome the dengue problem, house owners/residents can put ABATE every 5 days in the drains in the front of their houses to break the breeding cycle of the Aedes mosquitoes. Other less costly ‘chemical’ items such chilli powder; salt, old medications can also be put into the drains as cheaper alternative to ABATE so that there is some chemical substance in the drain water. I stand to be corrected on this.
(Note: Water in the drains flow in one direction, never in two directions, i.e. from the higher to the lower level).

The large monsoon drain (of trapezoidal cross-section) that cuts through SS 14 and SS 18
is another major breeding ground for the Aedes mosquitoes since many portions of the drain has become damaged over the years and vegetation has grown instead thus hampering the free flow of water when there is no rain. This can be the source of still water for the Aedes mosquitoes to breed.