Ugandan mosquitoes are resistant to DDT â€" study

May 02, 2005

SEVERAL mosquito varieties in Uganda have a strong resistant gene (kdr) against several insecticides including DDT, a new report has disclosed.

By Kikonyogo Ngatya

SEVERAL mosquito varieties in Uganda have a strong resistant gene (kdr) against several insecticides including DDT, a new report has disclosed.

DDT is under consideration for use in spraying the inside of the walls of residential houses to control malaria causing mosquito population. Dr Ambrose Talisuna, Assistant Commissioner Epidemiological Surveillance in the Ministry of Health presented the findings at a senior doctors lecture on the malaria situation in the country on April 19, in Kampala.

“Apart from mosquitoes in Arua and Jinja, more than 25 % of the mosquitoes in other parts of the country such as Apac, Tororo, Kanungu and Kyenjojo have this gene,” Talisuna said. He advised that an assessment for the levels of resistance of the different insecticides to mosquitoes needs to be conducted to guide the country on the best option to use for spraying.” Talisuna said their data suggest that the most effective option in spraying is deltamethrin, followed by permethrin then DDT.

Permethrin and Deltamethrin are also used in the treatment of mosquito nets.

“Permethrin is more fatal to mosquitoes than DDT. It will take about 20 minutes to kill 50% of mosquitoes exposed to it. DDT will take about 50 minutes. If you want to kill 95% of the mosquitoes, permethrin will take 50-60 minutes, while DDT will take 120-200minutes,” the expert said.

However, he noted that permethrin and deltamethrin are far more expensive than DDT.

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