Bangladesh’s wake-up call on the growing threat of dengue, chikungunya, and zika
We have just endured one of the deadliest years of dengue in our history. With chikungunya and zika season approaching, the situation could spiral out of control if immediate measures are not taken
I was in the vibrant city of New Orleans, attending the American Society of Tropical Medicine and Hygiene (ASTMH) Annual Conference, which took place between 13 November and 17 November. There, over 4,000 global experts and researchers convened to share their latest findings on tropical medicine and public health.
Among the many enlightening sessions, one in particular captured my attention: "The Rising Tide: Dengue Fever and Climate Change". Attending this session made me realise how critical this topic is for Bangladesh, especially as we grapple with a mounting public health crisis caused by vector-borne diseases.
The session brought together some of the world's leading experts, including Dr Mauricio Nogueira from FAMERP, Brazil; Dr Erin Mordecai from Stanford University, and Dr Shafiul Alam from icddr,b. Their findings shed light on the alarming connections between climate change, vector dynamics, and public health—and their relevance to Bangladesh is undeniable.
Dr Erin Mordecai highlighted the profound impact of anthropogenic climate change on dengue. She revealed that human-induced warming is responsible for 19% of the current global dengue burden. Worse yet, as temperatures rise, this burden is projected to increase by 61% by 2050.
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Warmer climates allow Aedes mosquitoes to expand their geographic range, extend their breeding seasons, and accelerate virus transmission cycles. These findings show the urgency of addressing climate change as a key driver of vector-borne diseases.
Dr Mauricio Nogueira from Brazil shared insights that resonated deeply with our struggles against dengue. Brazil is battling a surge in Aedes mosquito-borne diseases—dengue, chikungunya, and zika—each presenting unique challenges but often overlapping in symptoms.
His findings offered not just a glimpse into Brazil's proactive measures but also stark reminders of the gaps in Bangladesh's response.
One key issue highlighted was the growing complexity of dengue reinfections.
Rapid diagnostic tests, commonly used to detect dengue, are often ineffective in cases of reinfection, missing up to 40% of cases. This happens because, in secondary infections, the IgG antibody response dominates, while other markers, such as NS1 and IgM, remain low, leading to misdiagnosis.
Undetected cases pose severe risks, as timely treatment is crucial for preventing complications.
Even more troubling was the revelation about chikungunya. Clinically, it is nearly indistinguishable from dengue, sharing symptoms like fever and joint pain.
However, rashes and severe joint inflammation are more pronounced in chikungunya, though these distinctions often go unnoticed. This diagnostic confusion leads to underreporting of chikungunya cases, many of which are mistakenly classified as dengue.
Brazil's situation serves as a cautionary tale. Despite facing similar challenges, they have managed to keep their dengue mortality rate at 0.5 per thousand population—a figure far lower than Bangladesh's alarming 5.3 per thousand. Their success lies in robust year-round vector control, meticulous surveillance, and clinical care.
Dr Shafiul Alam from icddr,b shed light on the evolving crisis in Bangladesh, which is now on the brink of an even more complex health emergency.
Chikungunya, first detected in 2008, caused a massive outbreak in 2017, infecting nearly a million people. While those affected gain immunity for 8–10 years, growing evidence suggests that chikungunya could resurface by 2026, as immunity wanes in previously affected populations.
At the same time, the recent detection of the zika virus in Dhaka adds another layer of complexity. Although zika is less fatal, it is linked to serious neurological complications, such as Guillain-Barré Syndrome, and severe congenital disabilities when it infects pregnant women.
With all three Aedes-borne viruses—dengue, chikungunya, and zika—potentially circulating in Dhaka simultaneously, our public health system could face an unprecedented challenge. Yet, there seems to be a dangerous level of complacency in addressing these threats.
Equally critical is the need for nationwide, year-round vector surveillance and control. Aedes mosquitoes do not adhere to seasons, and neither should our interventions. Communities must also be engaged in eliminating breeding sites and adopting personal protective measures.
This is not fear mongering; it is a call to action. Bangladesh must act decisively to strengthen its defences against vector-borne diseases. Clinical guidelines need urgent updates to account for reinfections and overlapping symptoms of dengue, chikungunya, and zika. Healthcare providers must be equipped with tools and training to differentiate between these diseases and manage cases effectively.
Brazil's example shows that with timely action, we can mitigate the impact of Aedes-borne diseases. The stakes for Bangladesh, however, are higher than ever.
We have just endured one of the deadliest years of dengue in our history last year. With chikungunya and zika now in the mix, the situation could spiral out of control if immediate measures are not taken.
The time to act is now. Every missed opportunity to strengthen our public health response brings us closer to a crisis we cannot afford. Let us rise to the challenge before it is too late.
A K M Tariful Islam Khan is a science writer. He can be reached at tarif71@gmail.com.
Disclaimer: The views and opinions expressed in this article are those of the author and do not necessarily reflect the opinions and views of The Business Standard.
