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Mosquito
winning dengue war Latest research done by these scientists in Colombo on the deadly dengue mosquito is showing some alarming results. According to the research the mosquito has begun to build strong resistance to the insecticides used for its eradication in Sri Lanka's urban and suburban areas. Research has proved that Malathion, the primary agent used by local councils in the country, is showing a disturbingly low rate of success in tackling the dengue problem. Aedes Albopictus or the Asian Tiger mosquito, a dengue vector, has crossed the 50 percent mark in resistance to Malathion in Colombo. "This mosquito which is indigenous to Sri Lanka and the region is most active in suburban areas," scientists say. In the same research, the Asian Tiger mosquito has shown as much as 62.9 percent resistance to DDT in Kurunegala. Scientists say this is a clear indication of the long last resistance build up in the mosquito's genes as DDT was used as an insecticide in the 1960s. Scientists say this is an alarming trend and Sri Lanka will have to seriously look at further research. Sri Lanka has to find the resistance status so that it can use the best mix of insecticide to manage this dengue vector. The research was done by Dr. H.T.R. Jayasooriya of the Open University in Colombo and Dr. I.S. Weerasinghe of the Medical Research Institute under a Welcome Trust Grant from Britain. The research shows that in Colombo the Aedes Aegypti, another dengue mosquito, has shown 84.1 percent resistance to Propoxur, a commonly used insecticide. "We should prevent resistance development in the mosquito which may result in control failure," says Dr. Jayasooriya who assumes that although resistance has reached high levels in certain areas, "we have not yet reached control failure through insecticides". According to Dr. Jayasooriya, community control of this situation is the best method. Other methods would be spraying chemicals in rotation but all this has to be scientifically studied. "The spraying itself is not efficient because they spray things that should not be sprayed. For instance these two species don't breed in drains and dirty water collections. They breed in fresh water areas like gutters, tins and tires, yet I have seen spraying going on against dengue in the drains" says Dr. Jayasooriya. |
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