Opinion Desk: Experts fear an even worse outbreak of dengue due to increasing Aedes mosquitoes before monsoon

Amid the coronavirus scare following the detection of three cases in Bangladesh, another dangerous disease, dengue, is lurking around the corner with the gradual rise in its infection rate well before the monsoon, said experts.

They also warned that the capital city may witness an even worse outbreak of dengue this year than last year, as the number of Aedes mosquitoes is already very high   now  in early spring, reports UNB.

Two recent surveys — one by the Directorate General of Health Services (DGHS) and another by a team of researchers from Jahangirnagar University — found an alarming level of aedes mosquito larvae in different wards of Dhaka South City Corporation (DSCC) and Dhaka North City Corporation (DNCC).

The Breteau Index (number of infected water containers per 100 houses inspected) of aedes mosquito was 20-30 points at many wards of the two city corporations, which is very alarming.

Bangladesh experienced a massive dengue outbreak last year. The government confirmed that dengue claimed the lives of 164 people last year while 101,354 were hospitalized with dengue in the country.

According to the DGHS, at least 262 dengue cases were reported in the country since the beginning of 2020, with two hospitalized in the last 24 hours till 8am on Saturday.

Research by Jahangirnagar University

Contacted, Kabirul Bashar, an entomologist of Jahangirnagar University who led a research survey of aedes mosquito prevalence in the two city corporations, said 56 people were infected with dengue in January-February last year while 139 dengue patients were identified during the same period this year, indicating the greater density of aedes mosquito in the capital.

He said as light rain has started occurring since early this month, the scientific prediction model suggests the number of dengue patients will increase substantially this year than last year if proper steps are not taken right now.

“The rainy season will begin in full swing from June and dengue is likely to break out badly if the density of the aedes mosquitoes cannot be reduced and the breeding grounds cannot be destroyed,” he said.

The JU Professor said construction sites, bus terminals, police stations where many seized vehicles are kept in open spaces, the front and backyards of hospitals and various government establishments are the main breeding places of aedes mosquitoes.

Kabirul said the two city corporations need to become active now to kill mosquitos though there was no visible drive in this regard over the last three months.

About the findings of their survey conducted earlier, Kabirul said, the mosquito Breteau index in some areas of the two city corporations was over 25 percent, and 200 aedes mosquito larvae were found in 500ml of water, which indicates a high density of the aedes mosquito in the city.

DGHS research

In their recent survey, Abul Kalam Azad, director general (DG) of DGHS, said they found the aedes population is at a risky level in 12% of DSCC wards and 10% of DNCC wards.

He said the aedes Breteau Index of Dhaka North City Corporation’s wards 12, 16, 28, 31 and 1, and Dhaka South City Corporation’s wards 5,6,11,17,37 and 42, are  more than 20 points.

Assessing the survey results, the DG said dengue may badly spread this year if the breeding grounds of the aedes mosquito cannot be destroyed right now.

DNCC Chief Health Officer, Brigadier General Md Mominur Rahman Mamun said they are conducting mosquito killing and awareness raising activities in the vulnerable areas.

He said they have been working since January to control the outbreak of aedes mosquitoes in the rainy season.

He urged people to clean up their homes, buildings, and adjacent areas. “Don’t throw waste here and there, and do not allow water to be stored anywhere.”

DSCC Chief Health Officer Brigadier General Sharif Ahmed said they undertook a special crash programme on February 26 to destroy the sources of aedes mosquito while wards no 5,6,11, 17,37 and 42 were declared vulnerable.