A cross-sectional seroprevalence map (right) of dengue risk in Bangladesh, based on data collected from 70 communities throughout the country (Salje et al., 2019), shows that the risk is highest in the cities of Chittagong (in the south east), Khulna (south west) and Dhaka (in the middle of the country). Previous maps, such as this map based on data from Bhatt et al. (2013) (left), have predicted more widespread risk throughout the country, but these maps were largely based on less detailed data and often relied on extrapolation from nearby countries. This new study by Sajle et al. may suggest that there are unique, as yet unknown, factors that constrain the current distribution of dengue in Bangladesh.