As rising numbers of dengue patients strain hospitals across the country, a government survey in Gazipur and Narayanganj has found numerous breeding grounds of Aedes mosquitos.

The survey by the health directorate found Aedes larvae in 150 houses out of 1,050 visited in Gazipur and 95 out of 705 in Narayanganj.

Between July 23 and 28, the researchers visited 41 out of the 57 wards in Gazipur city, and from July 30 to August 3, they visited all the 27 wards in Narayanganj city.

Experts fear that the mosquito-borne disease may spread further if the authorities do not immediately destroy the breeding grounds to control Aedes population, the carrier of the dengue virus.

At least 398 people died of dengue this year, and 147 of the patients died this month, according to the Directorate General of Health Services (DGHS).

As of yesterday morning, the number of confirmed cases was 85,411 across the country, and 688 dengue patients were hospitalised in Gazipur and 381 in Narayanganj.

A statement from the directorate yesterday said at least 11 dengue patients died and 2,905 new cases were detected across the country in 24 hours. Of the new cases, 1,863 were reported outside Dhaka.

According to the survey, the density of Aedes in the two cities is very high, and as rains will create more breeding grounds, the people of the city will be at greater risk, said Mohammad Kholilur Rahman, former chief entomologist at the DHGS, who led the survey.

As there is a scarcity of running water in both the cities, residents tend to store water in buckets or large pots. These containers often become ideal breeding places for Aedes.

The researchers saw small containers and pots that can become a breeding ground in many houses and open spaces in both cities, Kholilur added.

According to Kabirul Bashar, entomologist at the Jahangirnagar University, the mosquito control measures are not properly taken outside Dhaka.

"The government as well as the residents of those cities do not give as much attention to controlling Aedes mosquitoes as they do in Dhaka," he said.

According to GM Saifur Rahman, entomologist at the National University, the absence of surveillance at the district towns has been a major failure this year.

"The government must have effective surveillance to identify dengue hotspots. This will enable local government departments, community organisations, and educational institutions to conduct targeted interventions," he said.

The city corporation officials and the residents share the responsibility to curb mosquito infestation by creating awareness, cleaning houses, and eliminating potential breeding grounds, he added.