The 2023 fatal dengue outbreak in Bangladesh highlights a paradigm shift of geographical distribution of cases

In 2023, Bangladesh experienced its largest and deadliest outbreak of the Dengue virus (DENV), reporting the highest-ever recorded annual cases and deaths. Historically, most of the cases were recorded in the capital city, Dhaka. We aimed to characterize the geographical transmission of DENV in Bangladesh. From 1 January–31 December 2023, we extracted and analyzed daily data on dengue cases and deaths from the Management Information System of the Ministry of Health and Family Welfare. We performed a generalized linear mixed model to identify the associations between division-wise daily dengue counts and various geographical and meteorological covariates. The number of dengue cases reported in 2023 was 1.3 times higher than the total number recorded in the past 23 years (321,179 vs. 244,246), with twice as many deaths than the total fatalities recorded over the past 23 years (1705 vs. 849). Of the 1,705 deaths in 2023, 67.4% (n = 1,015) died within one day after hospital admission. The divisions southern to Dhaka had a higher dengue incidence/1000 population (2.30 vs. 0.50, p <0.01) than the northern divisions. Festival-related travel along with meteorological factors and urbanization are likely to have contributed to the shift of dengue from Dhaka to different districts in Bangladesh.