Dengue infection: 13 Dhaka wards at high risk

Some 13 wards across the two city corporations in the capital have been identified as high-risk zones for dengue, with seven under Dhaka South City Corporation and six under Dhaka North.

In these wards, the density of Aedes mosquito larvae, the primary vector for dengue, exceeds the critical threshold, according to a pre-monsoon survey conducted jointly by the Communicable Disease Control programme of the Directorate General of Health Services, and the Institute of Epidemiology, Disease Control, and Research.

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Aedes larvae density is measured using the Breteau Index (BI), which assesses the number of positive containers per 100 houses inspected. A BI over 20 indicates an uncontrollable situation and a heightened risk of a dengue outbreak, according to global standards.

Among the 99 wards surveyed across DNCC and DSCC in February, March and May, 13 exceeded the BI threshold of 20.

The survey found DNCC's ward 12 (BI: 26.67); wards 2, 8 and 34 (BI: 23.33 each); and wards 13 and 22 (BI: 20 each) to be at high risk.

In DSCC, wards 31 and 41 (BI: 26.67 each); wards 3, 46 and 47 (BI: 23.33 each); and wards 4 and 23 (BI: 20 each) were found to be in high risk.

Among the breeding sources identified, cement water tanks accounted for the highest proportion (22 percent), followed by flooded floors (20 percent).

The other sources included plastic drums (13 percent), water meter holes (11 percent), plastic buckets (10 percent), flower tubs and trays/plastic pipe pits (7 percent), discarded tyres (6 percent), internal water channels (5 percent) and cement plots (4 percent).

The highest concentration of Aedes mosquito larvae (58.88 percent) was found in multistorey buildings, according to the survey, which was published yesterday.

The other breeding grounds included under-construction buildings (19.63 percent), independent houses (9.8 percent), semi-pucca houses (8.88 percent) and vacant plots (2.8 percent).

To combat the growing risk, the report urged several measures including community-based interventions to eliminate breeding grounds and enhanced coordination with REHAB and flat owners' associations, especially in multi-storey and under-construction buildings.

A year-round larvicidal programme in wards with high BI and House Index; a nationwide cleanliness drive involving schools, civil society, youth groups and other stakeholders; and regular dissemination of awareness messages through electronic and print media were also advised.

Authorities emphasised that immediate, coordinated action is essential to prevent a large-scale dengue outbreak in the coming monsoon months.