Some simple strategies to combat the dengue menace

Another breeding place is the gutter

By Ranjit Seneviratne

One of the concerns hitting the headlines is the rise of cases of dengue. Various efforts are being done by the authorities and the Colombo Municipality personnel have been going around clearing plants and insisting people who grow useful food plants like banana and aloe vera, etc. to remove them – not to mention flowering plants useful to encourage bees and butterflies already so absent in the city.

This appears to be a sort of “knee-jerk” reaction because if it were plants that harboured or allowed breeding of the dengue-carrying mosquito, then dengue should be rampant in villages with so much vegetation around them. The reason for this is perhaps because plants are known to exude oils and bio-chemicals from their surfaces (much like humans exude salty sweat from the skin’s surface) and the dengue mosquito does not like to breed in such chemically polluted water. It is known to breed in clean water.

On the contrary, dengue is rampant in cities that are densely populated and near schools – in other words where there are people and children who throw plastic yogurt and ice cream cups and plastic bags all over the place as well as ‘thambili’ and coconut shells.

Therefore is it not wiser for the authorities to insist that ice cream should only be sold in “eatable” cups (like the ice-cream cones) – even yogurt could be sold as frozen yogurt in “eatable” cups. Thambili sellers should collect their shells in gunny bags – and be fined if they leave them around.

Eliminate plastic bags

Another source of clean water that is favoured by the Anopheles Aegyptus Mosquito (implicated in the spread of dengue) are plastic bags. Therefore it is in everyone’s interest if the authorities eliminate plastic bags and insist that only paper or Jute-hessian or woven leaf (Dumbara Mat “Pang” and Palmyra leaf) bags be used. 

This will in addition, help our rural people and the recently settled people in the North where Palmyra is plentiful to have gainful employment and help reduce poverty. (Poverty Elimination under the United Nations sponsored Millennium Goals Project). 

Other more public places where water collects are drains, because we the unthinking public, are known to carelessly throw rubbish into drains thus blocking water flow. It is understood that the present practice is to spray toxic chemicals into these drains. As the drains are not water-tight, these harmful chemicals leak into ground water and could poison us – the people. The effect is not immediate but these chemicals are known to gradually accumulate especially in the fat cells and over time could cause cancer and even other non-communicable diseases.

A simple and inexpensive solution is to spray used engine oil (most of the harmful additives in the oil are “burnt up” in used oil). The oil forms a film on the surface and the larvae of the mosquito during the pupal stage (when it is shaped like a “comma”) is an air breather and comes to the surface to breathe. The oil chokes the breathing tube and kills the pupal stage mosquito larvae. 

Another solution is called “Holy Basil” in English (as it is worshipped by Hindus) and is a potent Adaptogen (like Korean Ginseng) – that is, something that strengthens the body’s immune and other systems. Holy Basil was found by researchers in India to be particularly useful in increasing the body’s immunity against viral diseases – and dengue is a viral disease. This herb can be consumed during any breakout of viruses. 

Stop water collecting in gutters

Another breeding place is the gutter and it is understood that some of the authorities concerned want to impose a “No Gutters” policy for new buildings. Again there is a very simple way to stop water collecting in gutters of both old and new buildings. It needs someone to go up to the roof, pour some water into each of the gutter lengths and to note where it collects (usually at the centre of the gutter length as plastic gutters sag with time). The next step is to drill a small hole (1 mm diameter) at each of these lowest points in the gutters. Then wrap a wire (preferably of non-rusting material) or nylon fishing line (thangus) round a small brass screw and thread the wire/nylon line through the hole in the gutter and lead it to the ground by wrapping the other end round another brass screw or even a stone and burying it a few inches into the ground. 

Water therefore cannot collect in gutters as it will quickly leak off into the ground without making an unsightly hole or splashing mud on the adjacent walls if there was no wire/nylon to “lead” the water into the ground. If the holes get blocked by dirt and/or slime – all you need to do is to “jiggle” the wire up and down to clear the block.

I have done this in my home – 8/1, Charles Drive, Colombo 3 and have been officially appointed by the “Praja Police” (Community Police) to help them with their “Surakimu Lanka” project to propagate these ideas (as well as Food Gardening).