Dengue outbreak in Dhaka: A policy failure?

Last year, it was me and this year, it was my father — both of us suffered from dengue fever. And we were just two among the thousands of dengue patients, falling victim to an outbreak that has escalated to record-breaking levels in recent years. 

Until 1 December, 494 patients died from dengue across the country. Among them, 209 of them died in Dhaka South City Corporation and 89 in Dhaka North. 

Last year, dengue claimed the lives of 1,705 people, making it the deadliest year on record. And 58% of the dengue deaths in the country were from the two city corporations of Dhaka. The role of the two city corporations in the capital in dengue control was rightfully criticised by many.

Despite substantial investments in mosquito control, the problem remains persistent, exposing deep-rooted policy and governance failures. 

Why is the death toll and infection rate so high?

Historically, dengue outbreaks were seasonal, peaking during monsoon, but the disease has become a year-round menace due to poor urban planning, unregulated construction, and inadequate waste management. Entomologists note that Aedes mosquitoes are now breeding in unconventional places, such as water storage containers in densely populated areas, drainpipes in high-rise buildings, and open construction sites. 

Over the years, Dhaka, the epicentre of the crisis, has accounted for the majority of all dengue-related deaths. Experts attribute this to the failure of city corporations in effectively managing mosquito control programs. For instance, fogging — a widely used method to kill adult mosquitoes — has proven to be largely ineffective.

Ex-president of the Bangladesh Zoological Society, Entomologist Manjur A Chowdhury, said, "There is no field-level survey to assess whether the dengue control efforts are effective. According to our research, less than 10% of mosquitoes are killed after fogging. Similarly, after applying larvicides, over 30% of mosquitoes in most drains remain unaffected."

Last year, at the height of the dengue outbreak, experts pointed out that dengue control is a technical issue - the biggest problem here is the lack of good governance, as good governance is essential in Aedes mosquito control. And this year, the situation is still spiralling, showing that good governance has not been ensured. 

Moreover, the healthcare system is ill-equipped to handle the influx of patients. Hospitals frequently run out of essential supplies like saline, and there is a lack of adequate diagnostic facilities outside Dhaka. Vulnerable populations, such as children and the elderly, bear the brunt of the epidemic, with delayed diagnoses and treatment contributing significantly to the mortality rate.

Virologist and public health specialist Dr Mushtaq Hussain thinks that the dengue crisis is a policy failure. "Our doctors and medical facilities are doing their duties well. But the root of the crisis is the policy approach," he said. 

"Dengue is a public health problem. Treating patients is the last step of a long list of preventive measures. To combat a public health crisis like dengue, you need a community-based public health approach.

"City corporations alone cannot contain dengue outbreaks. We need to decentralise our medical facilities, increase testing at community levels, and ensure early and fast diagnosis. Sometimes, the poor patients do not have the means to realise that they are affected by dengue. They wait, and since there are no proper dengue diagnosis facilities outside Dhaka, they need to come here. Until then, their condition worsens," Dr Hussain added. 

Policy failure: Mismanagement and flawed strategies

The policy failures contributing to Bangladesh's dengue crisis are numerous, compounded by a lack of foresight, ineffective governance, and a rigid adherence to outdated methods. These missteps are particularly glaring when juxtaposed with the substantial funds allocated to mosquito control. 

The Dhaka North and South city corporations have spent over Tk1,300 crore in the past 13 years. To control Aedes larvae, guppy fish were released into drains, Bacillus thuringiensis israelensis (Bti) tablets were applied to water bodies, and ducks and frogs were released into ponds and ditches. Additionally, drones were used to identify mosquito breeding hotspots. 

Despite this, the efforts have proven inadequate, with both infections and fatalities reaching alarming levels year after year. 

Bangladesh's reliance on chemical control methods, primarily fogging and larvicide spraying, reflects an outdated and myopic strategy. These measures are not only ineffective, but also fail to address the root causes, such as mosquito breeding grounds. 

GM Saifur Rahman, an entomologist and faculty member at the National University, told TBS, "We first need to find out why dengue spread from Dhaka to the rest of the country. The root cause lies in the methodological flaws in our Aedes mosquito control efforts. 

"Dengue-carrying Aedes mosquitoes must be controlled using the Integrated Vector Management [IVM] approach. For this, a separate organisation or body needs to be established, one that will conduct year-round research on dengue and determine what measures should be taken in which areas," he said. 

The IVM approach, which has been successful in other dengue-endemic countries, employs a mix of biological, mechanical, chemical, and environmental strategies tailored to specific regions.

Ex-president of the Bangladesh Zoological Society, Entomologist Manjur A Chowdhury, said, "There is no field-level survey to assess whether the dengue control efforts are effective. According to our research, less than 10% of mosquitoes are killed after fogging. Similarly, after applying larvicides, over 30% of mosquitoes in most drains remain unaffected." 

Further compounding the problem is the lack of coordination between the city corporations. Dhaka North and Dhaka South operate independently, with no unified action plan. This creates inefficiencies and often allows mosquitoes to migrate between regions when one area initiates control measures while the other lags behind. 

However, Dhaka South Chief Health Officer Dr Fazle Shamsul Kabir thinks that the dengue outbreak is still under control in the city corporation.  

"Only 5% of the dengue patients are from Dhaka South. The daily lists provided by the Department of Health present misleading information to the nation as patients from the southern city hospitals are counted as patients who caught dengue in the southern part of the capital," he said.  

"However, there are many large hospitals in Dhaka South where patients from all over the country come to receive treatment. That does not necessarily mean they are Dhaka South's patients. And less than one-fourth of the deaths listed under Dhaka South are actually from Dhaka South," Dr Kabir further said. 

"Last year, we used to receive concentrated cases from certain areas, but this year that is not the case," he added.

Dhaka North Deputy Chief Health Officer Rubayet Ismat Ovik said Bti will be applied soon and will reduce the Aedes mosquito population. "In July, our activities were hindered for a few days, which led to a significant increase in dengue because that was an ideal environment for the proliferation of Aedes mosquitoes."

Corruption and inefficiency have also plagued mosquito control programs. In their report titled 'Aedes Mosquito Control in Dhaka City: Governance Challenges and Way Forward', Transparency International Bangladesh (TIB) highlighted irregularities in pesticide procurement. 

Last year, reports revealed that the Bti procured for Dhaka North was not suitable for public health use and was deployed without adhering to established protocols. Later, the plan was scrapped, but such lapses waste public funds and undermine confidence in government initiatives. 

Another glaring issue is inadequate monitoring and evaluation. There is little effort to assess the effectiveness of mosquito control measures, leading to repeated failures. 

For example, despite conducting three annual mosquito surveys, the Directorate General of Health Services (DGHS) has struggled to translate findings into actionable interventions. This disconnect between data and policy action reflects poor planning and a lack of accountability.

The absence of community engagement is a critical flaw as well. 

While the government conducts awareness campaigns, these are sporadic and fail to empower citizens to take proactive measures in their homes and neighbourhoods. Without community buy-in, large-scale eradication efforts remain unsustainable.

Dr Mushtaq Hussain thinks that a community-centred approach needs to be taken to ramp up our efforts to contain the dengue outbreak. 

"Patient-centred approach should be the last resort," he opined. 

Two six-member expert committees, formed by the two Dhaka city corporations in response to a surge in dengue cases, have been working on this matter. So far, experts have already recommended ensuring the use of standard and specific doses of insecticides along with conducting a separate survey on mosquito-borne diseases alongside the DGHS.

"We have sat down for two meetings with the committee and they have given us some suggestions. We are evaluating the suggestions and have started to implement some of them in the field," said Dr Fazle Shamsul Kabir. "They will give us a short-term and a long-term plan shortly." 

The use of insecticides has been a centre-point of dengue prevention strategy. Dhaka South uses temephos larvicide each morning to combat mosquito larvae, while malathion and delta methylene are used for fogging in the afternoons. 

Dr Kabir said that the insecticides and larvicides are completely harmless for the environment. 

"The committee has not suggested any new insecticides. They said that they are satisfied with the insecticides' effectiveness. These insecticides do not harm the environment in any way and have WHO's clearance. Moreover, these are tested by two global-standard organisations — the Institute of Epidemiology Disease Control And Research (IEDCR) and Plant Protection Wing, Khamarbari," he further said. 

Impact of global trends on Bangladesh's dengue crisis

The escalating dengue crisis in Bangladesh is not occurring in isolation. Dengue is now a leading mosquito-borne disease worldwide, with the World Health Organization (WHO) declaring it a major public health concern. Bangladesh's struggles are intensified by international factors, including climate change, urbanisation, and global mobility.

Climate change plays a major role in the rising prevalence of dengue. Warmer temperatures and erratic rainfall patterns create ideal conditions for Aedes mosquito breeding. 

In Bangladesh, frequent waterlogging has significantly expanded the mosquito breeding season, making dengue a year-round threat. Research suggests that even small increases in temperature can accelerate the mosquito life cycle, leading to a higher density of vectors.

Additionally, rapid urbanisation in Dhaka and other cities has outpaced infrastructure development, resulting in overcrowded neighbourhoods with inadequate sanitation and water management systems. 

These conditions are ideal for mosquito proliferation. In many ways, Dhaka reflects the challenges faced by other fast-growing cities in developing countries, where unplanned construction and insufficient waste management amplify health risks.

Notably, Bangladesh has failed to adopt international best practices in dengue control, further exacerbating its challenges. Countries like Singapore and Sri Lanka have implemented comprehensive measures that combine early warning systems, community-based interventions, and cutting-edge technology. 

For instance, Singapore's use of traps to detect mosquito presence and its regular inspections of breeding sites have kept dengue outbreaks in check. Similarly, Kolkata's ward-level monitoring and proactive combing operations have demonstrated that local-level accountability can drive significant progress.

Bangladesh, however, lags behind in leveraging such innovations.