Bangladesh experienced the deadliest dengue outbreak this year, breaking all previous records by early November. The Directorate General of Health Services (DGHS) reported 279,904 hospitalisations and 1,408 deaths due to the disease.
Dengue is not new in the country. For about two decades now, outbreaks have been an annual occurrence. It is the rate and intensity at which the disease spread this year that led public health experts to issue warnings about the future.
In fact, this year, the world has witnessed more devastating dengue outbreaks in many other regions as well. Moreover, not just dengue and not just in Bangladesh, but climate change is likely to increase disease outbreaks around the world in several ways.
There is rising concern among public health experts and scientists that climate change could contribute to the increased risk of epidemics or outbreaks of infectious diseases.
Some of the correlating causes are: changes in temperature, precipitation patterns and ecological systems which can alter the distribution of disease vectors (organisms that transmit diseases), impact the life cycles of pathogens (disease-causing microorganisms) and affect human behaviour and vulnerability.
According to the Centers for Disease Control and Prevention, climate change can affect the distribution and behaviour of disease-carrying vectors like mosquitoes, ticks, fleas, etc.
In the case of Bangladesh and dengue, the evidence and track record warrants caution. Bangladesh is one of the countries most vulnerable to climate change, with a growing population of climate-change refugees — internally displaced people who move to the cities after losing their homes to extreme weather events. In the cities, rapid unplanned urbanisation and poor water storage practices do nothing to help limit or control the spread of infectious diseases.
A higher population density in the cities compounded with a poor healthcare system is likely to spell more intense dengue outbreaks.
There are vector-borne diseases — which means mosquitoes spreading dengue, malaria, etc. An increase in temperature increases the breeding [of these mosquitoes]," said Professor Mahmudur Rahman, a former IEDCR Director, "but we also have non-communicable disease outbreaks such as diarrhoea, which sees an increase with temperature increase."
So how does one tackle disease outbreaks?
Capacity building is one, said Professor Rahman. "There is something called the Public Health Emergency Operation Center, [in short] EOC, in almost every country, to respond to outbreaks. We have it, but not a functioning one. This is what is supposed to respond to an outbreak," he explained.
"There should be a national-level response team, district-level and upazila level," said Professor Rahman. He also pointed to WHO's One Health concept (an approach that recognises that the health of people is closely connected to the health of animals and our shared environment).
"We do have some training in place – some also came to an end for the lack of funds. But much more is needed," he added. From logistics support (lab support, sample transport support, etc) and outbreak detection, to a robust scheme to expand these detection methods, we need a lot more, according to Professor Rahman.
"There should also be something called an emergency fund to tackle an outbreak," he added, "on top of proper allocation of funds. And continuous advocacy is needed — for people working in certain health sectors to advocate for these [public healthcare initiatives] to those in positions of policymakers."
Bangladesh saw the deadliest dengue outbreak this year. What can help to resolve the worsening and contributing conditions of dengue outbreaks in the future?
"The most important thing is to have a National Strategy Plan," replied public health expert Dr Be-Nazir Ahmed, adding, "The health ministry has a key role to play here."
Funding and increasing the number of entomology labs, surveillance medical officers, manpower, and sufficient funds to carry out a nationwide strategy are all imperative. "Because, as we have seen, the dengue outbreak has moved beyond the cities," he said.
The crux of the problem, according to Dr Ahmed, lies in the absence of a coordinated national strategy. Another factor is community engagement. "Of course, raising awareness is important. But community engagement is needed," he said. The expert also said surveys of Aedes larvae, chemicals, reagents and insecticides are all important to redress the dengue phenomenon.
What's happening on the ground
"What we continue to see are ad-hoc measures undertaken by city corporations," explained Dr Ahmed, adding, "They are uneducated mosquito control staff and the spread is mainly associated with unplanned urbanisation."
The years 2020-21 serve as a stark reminder of the quality of the country's healthcare system. Yes, even developed countries fell victim and incurred high death tolls from the Covid-19 pandemic.
In the case of Bangladesh, the Institute of Epidemiology, Disease Control and Research (IEDCR) — the government research institute under the Ministry of Health, which is responsible for disease control — came under criticism by the public health experts, mainly for their delayed and slow response and shortsightedness.
However, when asked about its slow response to the pandemic, ASM Alamgir, Principal Scientific Officer of IEDCR, had said in 2021, "I beg to differ. IEDCR responded promptly and effectively from the very beginning. In fact, we worked preemptively."
He noted how in 2021, airports and other ports of entry were all covered by IEDCR. Alamgir stood firm in his stance despite how public health experts implored IEDCR for a better response.
Fast forward to Bangladesh's deadliest dengue outbreak year, in June 2023, IEDCR reported that people are getting affected with the DENV-2 and DENV-3 variants this season — the two with the highest rates of infections and death. In 2022 and 2021, DENV-4 and DENV-3 were found for the first time, respectively.
At this point, does IEDCR have plans to expand its surveillance or investigation capacity to monitor the dengue outbreak specifically for the future?
"We are doing investigations and surveys," replied Dr Tahmina Shirin, director of IEDCR. "We do not have plans to expand. This [climate change will increase infectious disease outbreaks] is based on assumption. We have one entomological lab."
During the pandemic years, a specialised Covid-19 hospital propped up in Mohakhali. The Dhaka North City Corporation hospital treated high volumes of patients during the peak of the pandemic. When the crisis subsided, so did the inflow of patients, but the well-equipped hospital sat idle, according to media reports from earlier this year.
When the dengue outbreak started to spread in May this year, there were calls to use the Dhaka North hospital for dengue care. In July, the hospital was declared a dedicated dengue hospital.
"That's a two-month delay," said Dr AM Zakir Hussain, a former Primary Care director at DGHS and also a former director at IEDCR. "That's the point. The bureaucratic protocols get in the way. I have seen how and to what extent first-hand in the past," he added.
"The problems are threefold: Resources, leadership and skill problems. It is a hotchpotch," said Dr Hussain.
Dr Be-nazir Ahmed said he is not aware of any plans required to tackle dengue outbreaks in future.