Twenty-one dengue patients died in the last 24 hours till 8:00am yesterday, the highest number of single-day casualties from the mosquito-borne disease in the country.

The total number of deaths from dengue fever now stands at 618.

Of the deceased, 19 were in Dhaka city hospitals, followed by one each in Mymensingh and Barishal, according to a press release from the Directorate General of Health Services (DGHS).

Thirteen patients, however, were brought to Dhaka from outside the city, due to what experts said was a detection and treatment gap outside Dhaka.

During the same period, 2,352 dengue patients were admitted to hospitals, raising the total number of patients hospitalised this year to 1,27,694.

The dengue cases may continue to rise as the ongoing survey by the DGHS revealed a high density of Aedes mosquitoes in 79 wards of two city corporations in Dhaka city.

"Dengue cases and deaths may continue to be as high as they are now throughout September. Because, as of Friday, we found the Breteau index to be very high, around 20, in the majority of the wards surveyed in the last eight days." Kabirul Bashar, entomologist and professor at Jahangirnagar University

— Kabirul Bashar, entomologist and professor at Jahangirnagar University

"Dengue cases and deaths may continue to be as high as they are now throughout September. Because, as of Friday, we found the Breteau index (BI) to be very high—around 20—in the majority of the wards surveyed in the last eight days,"  Kabirul Bashar, an entomologist and professor at Jahangirnagar University who is coordinating the survey, told The Daily Star.

BI is calculated as the number of containers with any larvae or pupae, divided by the total number of inspected households, multiplied by 100.

A total of 99 wards—40 in Dhaka North City Corporation and 59 in Dhaka South City Corporation—are being surveyed under the programme.

The survey will end today, according to Kabirul.

"The high BI reflects that the anti-mosquito drive has not been effective and is inadequate," he added.

Dr Mushtuq Hussain, consultant at the Institute of Epidemiology, Disease Control and Research (IEDCR), meanwhile, highlighted the absence of access to dengue testing services in rural areas.

"There is no dengue testing arrangement in upazila health complexes. As a result, people cannot even know in time that they have a dengue infection," Dr Mushtuq Hussain told The Daily Star yesterday.

He urged the government to arrange low-cost dengue testing services at people's doorsteps outside Dhaka.