The mosquito's day

Yesterday, August 20, was observed by the Congress as Rajiv Gandhi's 63rd birth anniversary. Neither the Congress nor anyone else, so far as can be made out, observed the day as the World Mosquito Day, though that is what it was. The day has come and gone without much notice by the public or by the public health authorities. The mosquito menace, which was curtailed at one stage through the national malaria eradication programme, has rebounded after that campaign lost its steam. In fact, the situation has been worsening steadily ever since the ban on the use of DDT, which remains the most effective and cheapest mosquito control agent. Malaria has therefore staged a comeback, and several other vector-borne diseases have become health hazards. Deadly diseases like dengue and chikungunya, unheard of till a few years ago, have become endemic in several areas. Nearly 2 million people are reckoned to have fallen prey to these maladies this year alone. The risk of other life-endangering diseases, such as Japanese encephalitis and yellow fever, cannot be ruled out if the country continues to be apathetic about mosquito control. The thought of a World Mosquito Day may raise a smile, but it happens to be a serious business.

Health is not the only area of concern. Mosquito infestation, if not controlled, can affect tourism, reduce livestock and poultry output, and lower real estate values in badly affected areas. An effective drive to keep the population of these pests under check is, therefore, a must. While the DDT ban is a matter of controversy (it is still in use in several developing countries), the fact is that this low-cost remedy is today not available. Most other pesticides are too expensive for mass application. Individual efforts, such as keeping homes free of mosquitoes by using killing or repelling agents, are of little avail if mosquitoes are allowed to breed unhindered in the neighbourhood. The solution lies in the realm of public health action.

The starting point of any integrated pest management campaign has to be the breeding grounds, which in the case of mosquitoes happen to be stagnant water, heaps of cut grasses and leaves and accumulated garbage. A strategy for mosquito management would have to go beyond the killing of mosquitoes and their larvae. Biological control measures can come in handy, such as predatory fish species. Besides, there are several kinds of nematodes and fungi that help arrest mosquito multiplication. Dead spores of some of the soil-borne bacteria, including the much talked about Bacillus thuringiensis (Bt bacteria), have also been observed to serve as biological mosquito control agents. The means to fight the menace exists.