City Bureau

Parks, restaurants, beach, bus stops, street corners, subways ... mosquitoes are everywhere . Is there a solution at hand?

CHENNAI: The buzz of the mosquito is growing louder by the day; repellents are burning holes in family budgets. And, with the city's residents fighting a losing battle with the winged predators, they are wishing the government and civic groups will start doing something soon to address the root causes of the problem.

The promise of a good water year -- with the full reservoirs -- had residents heaving a sigh of relief after the last monsoon. But nothing really prepared the residents for the onslaught of mosquitoes over the past six months. Mosquitoes have replaced water as the biggest civic problem.

Malaria is endemic to some parts of Chennai (see statistics) and residents have accepted it as an inevitable fact of life.

Successive governments have outlined grand plans for mosquito control, and the Chennai Corporation has succeeded in bringing down the number of malarial cases in the recent past, but that is just one part of the story.

Malaria is caused by female Anopheles mosquitoes -- one of three kinds of mosquitoes contributing to the menace. The other two kinds, Aedes Egypti and Culex -- also contribute substantially. While Anopheles and Aedes Egypti breed in fresh water sources, Culex -- sometimes referred to as the nuisance mosquito -- breeds in sewage water.

Entomologists at the Chennai Corporation say Culex mosquitoes are the biggest problem in the city today. B. Dhanraj, retired chief vector control officer and fellow of the Indian Society of Malaria and Other Communicable Diseases, says nearly 90 per cent of the mosquitoes in the city breed in storm water drains and canals. "Culex mosquitoes hunt in packs. These are the ones that are causing a huge problem in the city now."

Misuse of waterways

Storm water drains, if one goes by the definition, should carry only rainwater. In a city that receives the bulk of its rains in a one-month period, the drains should ideally remain dry for the rest of the year. But the ground realities are different.

Almost the entire length of the 800-km plus drain network and the 14 waterways of the city have sewage flowing through them throughout the year. In some instances, even Metrowater contributes to the sewage flow. Though government officials are aware of the problem, action has hardly been forthcoming for various reasons. It is also a myth that only lower-income groups -- such as slum dwellers -- illegally connect their sewage lines to waterways.

In recent years, the Corporation's health department has issued notices to individual houses to cover overhead tanks. This is a measure to control breeding. But, on the other hand, not much has been done to prevent waterways from turning to breeding spots. In effect, the city spends huge sums trying to repel mosquitoes rather than prevent breeding.

There have been some promising measures, however, of late. Chennai Corporation has promised to make the anti-mosquito campaign a community effort. Health Officer (in-charge) P. Kuganandam says the way forward is to associate health workers with the community. "The health worker must be available on call. The residents must personally know the sanitary worker and not come to the headquarters with complaints."

At a recent meeting with residents welfare group Exnora, Chennai Mayor M. Subramaniam appealed to residents' groups to purchase fogging machines. (A fogging machine costs Rs.45,000 and a spraying machine costs Rs.18,000.) "Why do you people have to depend on the government to do all the work? It is everybody's duty to keep the surroundings clean and prevent breeding of mosquitoes."

(Inputs from Karthik Subramanian, R. Sujatha, Susan Muthalaly and Swahilya)

What they say

B. Dhanraj, former chief vector control officer of Chennai Corporation:

The primary objective must be to prevent breeding. The Government can follow the Mumbai example where water connection is not given unless the well and overhead tanks are closed.

At the Chennai Corporation too, we initiated a project two years ago to issue notices to uncovered overhead tanks.

But what is the point covering up old tanks if new buildings are coming up with open tanks simultaneously.

The Government must amend the Town Planning Rules to ensure that open tanks are not allowed.

C.G. Ratnam, Anna Nagar resident, who has published a booklet on ways to control malaria:

The Chennai Corporation should resume distributing fishes such as guppies and gambusia in wells and ponds to control breeding of mosquito larvae.

Overhead tanks and wells must be sealed hermetically.

Even a minute gap of 1.5 mm is enough for the mosquitoes to gain entry into the tanks or wells and breed and pollute the waterbodies.

The Corporation must commence immediately spraying of pesticides on a large scale and on a regular basis.

It should also remove the vegetation from the canals andd other waterways to prevent stagnation of water and ensure a free flow Swaran Singh, Managing Director of the Tamil Nadu Water Supply and Drainage Board:

Controlling the mosquito menace is not just a tail-end solution, whether it is fogging the city roads or application of repellents and use of coils, mats, sprays or netting the windows at home... Fogging operations are temporary measures.

The real solution can be found only by keeping waterways and drainage systems clean.

Stagnating water and putrefying garbage act as receptacles for mosquitoes which breed in droves.

There is no better solution than keeping public spaces clean and dry.

Around the year 2000, when there was a massive cleaning of waterways, there was considerable relief from the mosquito problem, as it ensured a free water flow.