New modelling from icddr,b, shared with BHRF this month, suggests that the annual transmission window for dengue and chikungunya across the coastal districts of Bangladesh — Cox's Bazar, Bhola, Patuakhali, and parts of Khulna — could lengthen by six to nine weeks within the next decade as a result of warmer minimum temperatures and shifted rainfall patterns.
The modelling builds on a temperature-suitability framework developed by Mordecai et al., applied to downscaled CMIP6 climate projections for Bangladesh. The lead author, Dr. Tahmina Rashid, told BHRF that the results were "directionally robust but should not be read as deterministic" — the size of the window expansion will depend on how aggressively local mitigation, including elimination of breeding sites and vector surveillance, is implemented.
One implication is operational: the seasonal staffing models that the DGHS uses for its dengue response — a peak-period surge from August through October — may need to extend earlier and run later. Another is structural: clinical training and supply-chain planning in coastal districts need to assume an arboviral baseline rather than treating dengue and chikungunya as monsoon-only diseases.
"This is the kind of finding where the right response is not panic, it is operational," said BHRF Joint Secretary Shahnaz Begum, who has been coordinating BHRF's climate-and-health reporting cluster. "The lead time is long enough that we can adapt — if we start now."
The full modelling paper is currently in pre-print and will be linked from BHRF's climate-health resource page once it is publicly available.
