Aedes mosquitoes out of govt control: Prof Kabirul Bashar

Dengue has taken an alarming turn this year as a record number of people have been hospitalised with the Aedes mosquito-borne viral disease and many are dying every day. In a recent conversation with Prothom Alo, entomologist and professor of zoology at Jahangirnagar University, Kabirul Bashar, said that the Aedes mosquito population was out of the government's control.

Prothom Alo: Apart from ineffective mosquito insecticide and the failure of the city corporations, has climate change contributed to the increase dengue's severity this year?

Kabirul Bashar: Dhaka city witnessed the highest rainfall in February this year since 1953. The Aedes mosquito population increased manifold due to this year's heavy rainfall. Aedes mosquitoes' larvae can survive in nature at least six months in the dry season. These were laid by the mosquito population last November, December and January and Aedes mosquitoes emerged in huge numbers when the rains started in February. The rainfall expedited the breeding.

Prothom Alo: If that is so, the situation should be same to all cities of this region. Why didn't dengue take such a turn in Kolkata?

Kabirul Bashar: Bangladesh does not have any policy to eradicate mosquitoes. The city corporations target only Culex mosquitoes.

Prothom Alo: Dengue has been breaking out every year since 2000. There are agencies to tackle this, but why this negligence?

Kabirul Bashar: Directorate General of Health Services (DGHS) has a plan to survey various areas. Around 40 members of a team conducted a survey in 100 spots of 98 Dhaka wards in March 2019. Led by DGHS director Sania Tahmina, the team found the density of Aedes mosquitoes more than it should be. Carried out and financed by the DGHS, the survey predicted a dengue outbreak earlier in the season. I was also a member of the survey team.

Prothom Alo: You conducted a similar survey in July, too. Is there any difference in the latest survey in comparison to the previous one?

Kabirul Bashar: Obviously. The density of Aedes mosquitoes has increased more as there was more rainfall in July than that of February. If mosquitoes cannot be controlled, the dengue situation can deteriorate further. If it rains, the situation can linger up to October.

Prothom Alo: Where do we have lapses in controlling Aedes mosquitoes? And where do we have improvements?

Kabirul Bashar: Four tools will be required to controlling Aedes mosquitoes: 1. Environmental management, 2. Biological management, 3. Control of chemicals, and 4. Involving people. The city corporations only do the third, that is, control of chemicals. This year they have been trying to involve people, but that requires a year-long plan. It cannot be controlled without a coordinated plan.

Prothom Alo: What about the ineffectiveness of the insecticides?

Kabirul Bashar: When an insecticide is used for a long time, it loses its effectiveness and the mosquitoes become resistant to it. The new pesticide, which is used worldwide, will work.

Prothom Alo: We have heard that the government is going to buy Malathion. But this is used mainly for agricultural purposes.

Kabirul Bashar: Aedes is weaker than other mosquito species. It can bite four to five persons and infect with dengue in its lifespan of 21 days. The insecticide which can kill Culex can also kill Aedes mosquitoes. But the new insecticide should be tested in at least three laboratories before it is used. We, from the expert team, suggested that the government purchase Malathion 57EC, Malathion 5% RFU, Teltamethrin+PBU and Paramithas which are available in India, China and Germany.

Prothom Alo: What should the government do right now? If the capital Dhaka cannot tackle the dengue situation, how can the local governments throughout the country manage it?

Kabirul Bashar: Right now, Aedes mosquitoes are out of the government's control. These have spread to all 64 districts. The government, without delaying further, should sit with the experts and ask for direct help from the people. If people do not take part right now, the government cannot control things. The government has to raise awareness among people to identify Aedes mosquitoes and kill them to save themselves and their families. Only people can control this.

Prothom Alo: How has Kolkata been successful in controlling Aedes mosquitoes?

Kabirul Bashar: They prepared a good plan and implemented it.

Prothom Alo: Professor Nazrul Islam, virologist and former vice chancellor of Bangabandhu Sheikh Mujib Medical University, told us that dengue is absent from the MBBS syllabus and there is also a crisis of expert dengue physicians.

Kabirul Bashar: The symptoms of dengue change on regularly. For this, we have readied a guideline and a clinical manual for the physicians. These are available on the DGHS website.

Prothom Alo: Thank you.

Kabirul Bashar: Thank you.

*This report, originally published in Prothom Alo print edition, has been rewritten in English by Imam Hossain