Sustained efforts key to effective mosquito control

Mosquitoes are not any modern-day phenomenon. They are to be found even in ancient books on the biblical era, where it is narrated that emperor Nimrod, the builder of the Tower of Babel, suffered at the hands of a mosquito when it entered his brain through his nostrils and buzzed for twenty-four hours, making his life a veritable hell. So, he started to bang his head against stonewalls and died in the process. It will not be an exaggeration to say that humans have been fighting mosquitos since the dawn of history. In cities like Dhaka, that fight is often one-sided with the tiny creatures, in their millions, causing all sorts of troubles for the residents.

The two city corporations of Dhaka have tried many methods of mosquito control, often without success, despite claims by top officials that Bangladesh is faring better than many other Asian countries in preventing dengue and other mosquito-borne diseases. The methods applied so far include chemicals sprayed on bushes and drains, releasing a small fish variety called guppy in city drains as well as tilapia fish and ducks in ponds and lakes, flying drones for detection of larvae spots, etc. We are told that the Dhaka South City Corporation also released more than 15,000 frogs in various lakes, ponds and other water bodies in the hope that those would eat mosquito larvae and reduce the risk of dengue infection.

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Where have all the frogs gone?

But the move, which entomologists called "unthinkable", proved to be ineffective, as is evident from the fact that city-dwellers in many areas remain hostage to mosquitos, while large numbers of dengue patients continue to be hospitalised. Given the gravity of the situation, the Dhaka North City Corporation recently opened a control room to provide free dengue tests and advice regarding the disease. It also deployed a large number of drones to search for mosquito breeding grounds on building rooftops.

Experts, however, say that such methods and strategies are usually adopted at short notice, without taking their effectiveness or long-term consequences into consideration. They pointed out that the authorities have a tendency to control both Aedes and Culex mosquitoes by following the same methods, but in reality, the two need different approaches. Therefore, there is no alternative to getting our mosquito control policy right, as well as undertaking sustained efforts including surveillance, prevention and follow-up actions. The city corporations must work in collaboration with the experts to adopt the best policy and prevent the onslaught of mosquitos.