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Majority of insecticides used by Dhaka city corporations ineffective against mosquitoes

  • Published at 10:21 pm July 16th, 2019
A city corporation employee with a fogger spraying insecticide on the side of a city street
A city corporation employee with a fogger spraying insecticides to eliminate mosquitoes in Dhaka city Mahmud Hossain Opu/Dhaka Tribune

Sources from the city corporations said they are aware of the study and are trying to switch insecticides, but bureaucratic procedures mean the switch cannot be made immediately

The majority of insecticides used by the Dhaka city corporations are ineffective against Aedes Aegypti, the mosquito species responsible for spreading dengue fever, according to a recent study.

Sources from the city corporations said they are aware of the study and are trying to switch insecticides, but bureaucratic procedures mean the switch cannot be made immediately.

If suggested alternative insecticides are already registered in Bangladesh, the switch may take from one to two months. However, if they are not registered in the country, then the switch will take a minimum of six months, the sources added.

Funded by the US Centre for Disease Control and Prevention (CDC), researchers of the icddr,b collected Aedes Aegypti and Culex mosquito eggs from different areas of Dhaka, and found that the mosquitoes have developed near complete resistance against some of the insecticides the city corporations have been using for the past 10 years.

icddr,b researcher Mohammad Shafiul Alam said the study found that mosquitoes in Dhaka are fully resistant to Permethrin – the insecticide primarily used by the capital’s city corporations.

He added that Bendiocarb was found to be an effective alternative, but it is not registered in our country.

“Malathion and Deltamethrin are also effective alternatives, and these two are registered in the country,” the researcher further said, mentioning that the iccdr,b has been holding meetings with stakeholders to find a solution to the insecticide resistance problem.

Dhaka North City Corporation mayor Atiqul Islam said it would take at least five to six months to switch to different insecticides.

According to the DNCC mayor, Limit Agro, the company that used to supply insecticides to the DNCC, has been blacklisted as the quality of insecticides they supplied was repeatedly checked and found to be poor.

Dhaka North City Corporation (DNCC) Chief Health Officer Mominur Rahman Mamun said: “We are aware of the study and we know mosquitoes are resistant to some of the insercticides we are using right now. Currently, the DNCC is using Permethrin, Tetramethrin, and S-BioAllethrin to kill mosquitoes.

“We need a written document on the alternative insecticides for procurement. The alternatives have to be approved by the technical committee of the health directorate, and we have to seek a tender once approved,” he added.

“If I get a list of alternatives, we can start working on it right away. It would take about one and a half months to two months if the alternatives are registered in Bangladesh. If the insecticides are not registered in Bangladesh, it would take a minimum six months to get them registered,” Mominur further said, adding that any importer has to apply for registration.

He also said the older insecticides would not go to waste, as they still work on larvae.

Furthermore, the DNCC chief health officer said the city corporation  needs a dedicated laboratory and cell to monitor if mosquitoes were developing resistances to insecticides.

Dhaka South City Corporation (DSCC) Mayor Sayeed Khokon said the city corporations would only buy insecticides that are WHO approved.

Health Directorate National Program Manager (Dengue) Dr MM Aktaruzzaman recommended the use of larvicide on water pooling at construction sites, the placing of lids on buckets of water if they were used to store water for more than three days, and the regular cleaning of rain water to prevent mosquitoes from spreading.

A total 2,100 people have been infected with dengue since January this year. Among them, two have died, while 300 were admitted to hospitals and 1,875 returned home after receiving treatment.

In 2018, a total 10,148 people were infected with dengue, and 26 died, according to a Health Directorate report.