How (not) to fight mosquito

Mosquito-borne dengue was in the spotlight last year, setting a new record of infection and death from the disease in the past 19 years.

However, the two Dhaka city corporations were too obsessed with their old measures. They apparently were in love with fogging myth and washed their hands off after spraying and fogging pesticides.

Though the measures drew huge criticisms over their effectiveness, the city corporations' budgets for controlling the mosquito menace show gradual hike every year.

Meantime, experts advocated for coordinated approach like a mosquito control plan instead of spraying pesticides to combat dengue vector Aedes. They emphasised destroying its breeding grounds and cleanliness.

Highlighting awareness building, experts stressed "source reduction and vector control" of Aedes mosquito.

They warned that dengue may morph into an all-year disease and can take a dangerous turn.

Dr Kabirul Bashar, professor of zoology at Jahangirnagar University, told The Business Standard that there are four effective methods to control mosquito. And he suggested using those tools altogether.

The first one is environmental management, which evolves destroying the breeding grounds.

The second measure is biological control – deploying other living entities such as fish, bacteria or genetically modified mosquito to control the Aedes population.

Dr Kabirul said, "Biological control, also known as Ulbakia, can be tested in Dhaka, dividing the metropolis in smaller areas. For this, mosquitos will have to be locally bred instead of importing."

The third measure is spraying and fogging insecticides. It covers both larvicide for mosquito breeding grounds and adulticide or fogging to kill adult mosquitos.

The fourth is community perception, which ensures that mosquito breeding does not recur in a community.

"If the four methods are not put altogether, nothing would tame the intensity of dengue outbreak," said the entomologist who has been conducting researches on mosquitos for 20 years.     

Dr Kabirul Bashar said the methods are not applied in Bangladesh for combating Aedes. 

"We had been depending solely on spraying and fogging. Some initiatives were taken recently for awareness building, though," he added.

Meanwhile, a research conducted about one and a half years ago proved that mosquito sprays have become ineffective. 

Worldwide 725,000 people die of mosquito-borne diseases every year. Mosquito has been the world's deadliest animal year after year.  

According to the World Health Organisation (WHO), some 20,000 people die of dengue throughout the world every year. The mosquito-borne disease is also on the rise in Bangladesh.

Echoing Dr Kabirul, Prof Dr Meerjady Sabrina Flora, director of the Institute of Epidemiology, Disease Control and Research, also emphasised destroying the breeding grounds.  

Dr Flora said dengue spreading Aedes mosquito prevails round the year and the disease peaks up during monsoon.

According to the Directorate General of Health Services, as many as 101,354 people were hospitalised with dengue across the country in 2019. 

In that year, the Institute of Epidemiology, Disease Control and Research confirmed 156 deaths from dengue.

The first 19 days of this year saw 160 fresh dengue infections. In 24 hours until Sunday morning, four new dengue patients were hospitalised across the country.

According to Dr Flora, mosquito control activities should be carried out round the year, especially when the dengue infection rate remains low. 

"The output will be better if you strike when your enemy is weak," she noted. 

Meanwhile, Dr Kabirul Bashar suggested carrying out anti-mosquito programmes at grassroots level so that dengue outbreak cannot take a dangerous turn as it did in 2019.

"If we do not begin now, the peak season will be difficult. Therefore, measures must be taken from the beginning of the new year," the entomologist concluded.