As strong pre-monsoon rains sweep across Bangladesh, an unsettling trend is again emerging: cases of dengue fever rising earlier and faster this year.
In the first 27 days of May 2025, at least 1,450 people were infected with the mosquito-borne viral disease, according to data from the Directorate General of Health Services (DGHS). The number marks a 26 percent rise from the same period in 2024 and a 400 percent increase from 2023.
These numbers raise not just public health concerns but also policy questions. Should dengue be declared a reportable disease in Bangladesh?
Stronger pre-monsoon, earlier outbreak
Dengue cases have traditionally been known to spike between June and October, coinciding with the monsoon season, when waterlogging and urban drainage issues create ideal breeding grounds for the Aedes Aegypti mosquito. However, the mosquito life cycle started earlier this year due to unseasonal rains and high humidity in early May.
Climatologists report that rainfall in the first half of May 2025 was 35–40 percent above average, and temperatures stayed above 30 degrees Celsius – conditions ideal for Aedes breeding.
"This shift means dengue is no longer a seasonal phenomenon and it's becoming a year-round health concern," says Farzana Haque, public health specialist at Institute of Epidemiology Disease Control And Research (IEDCR).
Numbers paint a grim picture
In the first 27 days of May 2023, Bangladesh reported 261 dengue cases. This number increased significantly to 972 cases during the same period in 2024, showing a sharp 273 percent rise compared to the previous year. The situation has worsened further in 2025, with 1,450 cases recorded by May 27, representing an alarming increase of over 455 percent compared to 2023, and a nearly 49 percent rise from 2024.
Health experts are deeply concerned about this upward trend, warning that if the current pace of infection continues unchecked, Bangladesh could face a dengue outbreak worse than the severe epidemic of 2022, which resulted in more than 300 deaths. The rising numbers highlight the urgent need for strengthened public health measures, early detection, and comprehensive mosquito control programmes to prevent further escalation of this life-threatening disease.
Dengue types: Understanding the medical landscape
Dengue is not just one disease; it has several forms with different levels of seriousness. Dengue Fever (DF) is the most common form, which usually causes high fever, headache, and body pain. However, sometimes it can develop into more dangerous forms like Dengue Haemorrhagic Fever (DHF), where bleeding occurs, or Dengue Shock Syndrome (DSS), which can cause a sudden drop in blood pressure and be life-threatening. In Bangladesh, all these types are seen every year, and recently, severe cases like DHF and DSS are increasing in cities and nearby areas.
One important reason behind this rise is the presence of four types of dengue virus, called serotypes—DENV-1, DENV-2, DENV-3, and DENV-4. When a person gets infected by one serotype, they become immune to that type for life. But if they get infected again by a different serotype, the illness can become much more severe because the body's immune response can worsen the infection. Doctors and scientists pay close attention to which serotypes are spreading each year.
Zahirul Islam, a researcher at Dhaka Medical College, explains that many deaths happen because patients are not diagnosed early, and private clinics often miss the signs of severe dengue.
"In 2022, most deaths were caused by late referrals and misdiagnoses," he says. This shows how crucial it is to improve early detection, raise patient awareness, and ensure hospitals are ready to treat all forms of dengue effectively.
What happens when a disease is made 'reportable'
A reportable (or notifiable) disease is one that, by law, must be reported to health authorities upon detection. This allows the state to: track outbreaks in real time, mobilise emergency medical resources, launch targeted vector control programmes, and coordinate public communication and awareness drives.
Currently, diseases like tuberculosis, cholera, polio, and measles are reportable in Bangladesh. Dengue is not, meaning many private hospitals and diagnostic centres don't report cases, leading to reduced data and delayed interventions.
How a disease gets declared reportable in Bangladesh
Under the Communicable Diseases Act-2018, after consultation with the DGHS and IEDCR, the Ministry of Health and Family Welfare can issue a gazette notification to designate any disease as reportable.
This legal move makes reporting mandatory for all healthcare institutions, public or private, and enables the use of legal enforcement mechanisms during outbreaks.
Government's response: reactive or preventive?
The government of Bangladesh has taken several important steps in response to the rising dengue threat in 2024 and 2025. These measures include increased funding for fogging and larvicide programs, particularly in high-risk cities such as Dhaka and Chattogram, alongside piloting AI-based hotspot mapping projects supported by the World Health Organization. Community awareness campaigns have also been launched through mosques, schools, and television to educate the public on dengue prevention.
Public hospitals have expanded their dengue wards ahead of the monsoon season to prepare for a potential surge in patients. Moreover, the government has worked closely with city corporations to enhance waste management and clean drainage systems, while deploying mobile health units to provide immediate care in vulnerable slum areas.
However, experts warn that these efforts remain largely reactive rather than preventive. Aminul Haque, Director of Epidemiology at BRAC Health, emphasises that without legally designating dengue as a mandatory reportable disease, authorities often find themselves responding after outbreaks occur rather than preventing them. This represents a significant gap in Bangladesh's overall dengue control strategy.
Dengue and urban Bangladesh: A perfect storm
Dengue is not just a medical issue — it's a symptom of urban vulnerability.
Unplanned urbanisation, stagnant water on rooftops, broken drainage, and construction sites without mosquito control contribute significantly to the dengue problem. Studies show that 90 percent of dengue larvae in Dhaka are found in indoor containers, flower pots, rooftop tanks, and construction barrels. According to the "Entomological Survey of Dengue Vectors in Dhaka City" by icddr,b and the "Dengue Vector Surveillance and Control in Dhaka" published in the Journal of Vector Borne Diseases, these breeding sites are major contributors to the rapid spread of dengue in urban areas.
"We are fighting an urban disease with rural-style responses," notes Tahmina Ali, entomologist and urban health policy researcher.
A way forward: from reactive to proactive
To move from a reactive stance to a genuinely proactive approach in tackling dengue, public health experts are urging a comprehensive national strategy.
First and foremost, they recommend officially declaring dengue a reportable disease, which would mandate uniform case reporting across public and private healthcare facilities, ensuring real-time data integration.
Second, surveillance and vector control measures like fogging should be carried out throughout the year, not just during the monsoon months, as the shifting climate has made dengue transmission more unpredictable.
Third, experts stress the need for urban sanitation reform, calling on city corporations to coordinate closely with community leaders to address garbage management and stagnant water issues that fuel mosquito breeding.
Finally, a unified health dashboard that integrates data from both government and private sectors could significantly enhance transparency, tracking, and early warning systems. Together, these steps would shift from short-term containment to long-term prevention.
In addition to these measures, sustained public education campaigns remain crucial to raise awareness and encourage community participation in mosquito control. International partnerships can provide technical and financial support to strengthen national capacity. Research into dengue transmission dynamics and vaccine development should be prioritised to stay ahead of evolving threats. A coordinated response involving government agencies, healthcare providers, and civil society will be key to implementing these strategies effectively and protecting public health.
What the numbers now tell us
Bangladesh is no longer able to treat dengue as a seasonal inconvenience. With stronger pre-monsoon rains, rising temperatures, and expanding urban populations, dengue has become a public health emergency that requires legal, structural, and cultural change.
The key to tackling it lies not just in killing mosquitoes but in modernising our health governance, from tracking diseases to preparing for outbreaks and holding institutions accountable.
Dengue is no longer knocking. It's already inside the house.
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