Dengue Outbreak Escalates in Bangladesh: Co-Circulation of Two Serotypes Drives Highest Infection Rate in Three Years

Khairul Alam; Dbarta24 — Bangladesh is facing its most severe dengue outbreak in three years, driven by the alarming co-circulation of two distinct virus serotypes across urban and rural regions.

 

Official health data shows hospital admissions exceeding 40,000 as of early September, sparking grave concerns among public health experts that the country could face a crisis on par with the catastrophic outbreak of 2023.

The hospital crisis is intensifying rapidly. Outside the emergency department of a private hospital in Farmgate, Dhaka, Khalida Akter waited anxiously with her 22-year-old son, Fatemi, who was diagnosed with dengue.

 

After being turned away from two major public hospitals due to a complete lack of beds, she faced the daunting prospect of paying 8,000 BDT per night for a private cabin—an overwhelming sum for a school teacher.

“In the end, I have to take the cabin. My son’s life comes first,” Akter said. “A lot of money has been spent in three days, and more will go. There is no other way.”

Across the capital, similar stories abound. At the Bangladesh Shishu Hospital and Institute in Agargaon, five-year-old Alifa has been undergoing treatment since late August, while crowded public wards at Suhrawardy Hospital and Chittagong Medical College have forced some patients to receive intravenous fluids on hallway floors.

Data from the Directorate General of Health Services (DGHS) reveals an exponential rise in dengue cases over recent months:

This represents the highest record for the same period over the last three years, surpassing the 33,307 admissions recorded by early September 2025 and 14,325 in 2024.

 

Health authorities emphasize that official tallies only capture hospitalized cases, leaving thousands of mild or home-treated infections uncounted.

DENGUE ADMISSIONS TRAJECTORY (2026)
---------------------------------------
June     | 2,907
July     | 9,206   (▲ 216%)
August   | 20,536  (▲ 123%)
Jan-Sep4 | 40,044  (Highest in 3 Years)

Surveillance by the Institute of Epidemiology, Disease Control and Research (IEDCR) reveals a complex, “mixed profile” of circulating dengue strains. While DEN-3 has emerged as the dominant nationwide strain this year, DEN-2—which fueled the record-breaking 2023 outbreak—remains widely active, particularly in rural districts and regional hubs like Bandarban, Barguna, and Patuakhali.

World Health Organization (WHO) guidelines note that while initial exposure to one dengue serotype confers lifelong immunity against that specific strain, subsequent infection with a secondary serotype significantly heightens the risk of severe dengue hemorrhagic fever and dengue shock syndrome.

“The simultaneous presence of two major serotypes could be playing a key role in the rapid transmission seen this season,” said public health expert Dr. Mushtaq Hossain. “However, broader genomic studies are required to confirm this definitively.”

Health experts also warn of a potential late-year surge if a third serotype gains traction among young children born over the last five years who lack cross-reactive immunity.

Entomological surveys conducted by Jahangirnagar University highlight critical failures in vector control, particularly outside the capital.

 

The Breteau Index (BI)—which measures Aedes mosquito larvae density per 100 houses—exceeded 40 in regions like Bandarban during August. Public health standards dictate that a BI above 20 signals a high risk of an uncontrollable epidemic.

While Dhaka maintains a baseline healthcare and vector management infrastructure, district towns and rural areas lack basic mosquito mitigation programs and specialized medical beds.

 

Out of the 40,044 total cases reported nationwide, more than 30,000 have occurred outside the Dhaka North and South City Corporation areas, with Khulna division alone recording 6,324 cases and 19 deaths.

Responding to public criticism over hospital bed shortages, Professor Halimur Rashid, Director of Disease Control at the DGHS, stated that clinical management remains sound despite capacity constraints.

 

“Controlling transmission is not our direct responsibility,” Rashid said. “Regarding treatment, public hospitals always operate above bed capacity—this is not new, but medical care is being provided without flaw.”

However, IEDCR Director Dr. Kazi Ahmed Zaki expressed frustration over the gap between scientific research and field execution. “We conducted the field research, identified the mosquito density, and mapped the circulating serotypes,” Zaki noted. “I do not know to what extent those findings were implemented in vector control efforts.”

With monsoon rains continuing to create ideal breeding habitats in uncleaned containers and urban debris, entomologists warn that September could see dengue numbers spiral completely out of containment unless immediate, targeted mosquito eradication campaigns are executed nationwide.