Dhaka city corporations consider new strategies to battle mosquitoes
ASM Atiq lives on the third floor of a building in Dhaka’s Uttara. He uses mosquito screens on windows all the time, repellents during attacks and nets while sleeping. But nothing works to save his two daughters from the bites of the insect.
“The insects lurk around the mosquito net at night and slip in whenever they can,” he said.
Atiq has doubts about the effectiveness of the mosquito repellents sprayed by workers of Dhaka North City Corporation, reports bdnews24.com.
“We see the workers using fogging machines. They also spray some medicine in the drains during the morning hours. But the mosquitoes have not gone away,” the exasperated father said.
The residents of Dhaka are suffering as the density of Culex mosquito population has increased in the capital. Culex mosquito bite does not lead to dengue fever, but the attacks are no less annoying.
There has been a spurt in mosquito population this time due to excessive rains during the months of November and December, said entomologists.
The Dhaka North City Corporation is considering an area-based ‘crash programme’ to curb mosquito infestation while the Dhaka South City Corporation is changing its mosquito repellent.
Nur Ullah Sohel, a resident of Bashundhara, alleged they have been worse off than the previous year.
The mosquito menace was not that severe last March and in the few months that followed, Nur told bdnews24.com on Monday.
How was it under control then? Why can’t it be controlled now?
“The government has been unable to take any effective steps to control mosquitoes,” Sohel offered. “This is not a project worth billions of takas. The government simply lacks goodwill.”
There is a difference of opinion among the people on various issues, including politics, but there is none when it comes to mosquito menace, he said.
Mohammad Ullah from Mohammadpur said mosquitoes are unable to enter his eighth-floor home as he keeps the doors and windows shut all the time and his office is also safe from the insects.
He discovered the terrible feeling of being attacked by Dhaka’s mosquitoes after visiting his father-in-law’s house in Kalyanpur.
“The situation was so dire that I could pluck out a handful of mosquitoes from the air after sunset. There seems to be more mosquitoes this year than the previous years.”
According to a survey conducted by Kabirul Bashar, professor of zoology at Jahangirnagar University, the mosquito infestation in the capital this time is higher than the same period last year. He has been working on mosquito density since January 2020.
Six localities in Dhaka are selected for sampling every month and individual surveys are conducted in those areas, Kabirul said. For this purpose, mosquito density-measuring devices or dippers are installed at different places.
As many as 200 dippers were set up in each area. Each dipper was submerged in water once and the number of mosquito larvae it caught was counted after lifting it. After collecting all the samples, the average was calculated to find the density of mosquitoes in the particular area.
“The figure varies from place to place. Last year, we got an average of 35-40 larvae per dipper. But an average of 50-55 was found in February this year. If there is no crash programme to curb the mosquito outbreak and if there is no storm, then the number of mosquitoes can increase in March,” said Kabirul.
There was more rain than usual in November and December. The canals have filled up and the accumulation of water in these closed water bodies in Dhaka has offered a perfect breeding ground for mosquitoes to multiply, said entomologist Manjur Ahmed Chowdhury. As a result, the mosquito menace has more bite at this time of the year.
“Breeding sites have developed in the accumulated water. The more breeding sites there are, the more the Culex mosquitoes will reproduce. That is what has happened this time.”
A major storm would naturally reduce the number of Culex mosquitoes, said Manjur. But he advised a fast mosquito eradication programme.
“You can’t wait for the rain to come. I heard the DNCC will conduct an area-based programme. I’m hoping for a visible change if that happens.”
DNCC Mayor Atiqul Islam said he was looking for effective ways to end the mosquito menace. He also held a day-long meeting on the issue on Monday.
“I wanted to know from the entomologists the reason behind the increase in mosquito population. They said the infestation is bigger this time due to the excess rains.”
A regional crash programme will be launched in the DNCC areas on Mar 8 or 10, he said.
“I used to conduct ward-based crash programme. Now it’ll be region-based. We’ll deploy all the staff and equipment in 10 regions simultaneously. We want to see how it works. We need rain as well.”
ABM Amin Ullah Noori, chief executive officer of DSCC, was adamant that mosquito infestation has not spiralled out of control, not yet. He sounded confident that the initiatives taken to control mosquito, including eradication of its sources, will prove effective.
They have also changed the mosquito repellents.
“Malathion was used for fogging. We’re speculating the mosquitoes might have become resistant to the medicine due to its long-term use. We’ve consulted with an expert committee on this matter. We’re going to use Deltamethrin now.”
“We’ve sat down with the experts to determine the amount of diesel to mix with Deltamethrin,” Amin Ullah said.
“They gave us a formula. If we use our imported medicine according to the formula, we will be able to control the infestation even more.”