Human behaviour directs household-level exposure to malaria vectors in Bandarban, Bangladesh

Matthew A. Aubourg, Hasan Mohammad Al-Amin, Anoop Sunkara, Sanjna Chetan, April Monroe, Ching Swe Phru, Rashidul Haque, Wasif A. Khan, Allison Hendershot, Mohammad Shafiul Alam, Neil F. Lobo

Bangladesh has reduced malaria incidence and mortality by over 75% between 2010 and 2020. Widespread long-lasting insecticidal net (LLIN) distribution and use is one of the measures responsible for this success. Recalcitrant malaria hotspots within the Chittagong Hill Tracts districts suggest important drivers of malaria risk may remain uncharacterized. Towards understanding how household-level human behaviour impacts exposure to mosquitoes, parallel human landing catches and human behavioural observations were conducted in four households for 6 months (May-October) over the rainy season in the Bandarban District. Analysis quantifies spatiotemporal human behaviour-adjusted exposure to Anopheles with and without LLINs. This small-scale operational study demonstrates that human spatial and temporal presence along with LLIN use drives exposure to Anopheles. Though the four households had both outdoor and indoor exposure, especially in the evening (1800-2000 h) and early morning (0400-0500 h), data points to household-based heterogeneity in malaria exposure even with similar LLIN access. Incorporating human behaviour into exposure estimates can be used to understand the efficacy and limitations of local vector control strategies and identify gaps in protection, as well as where present intervention strategies may be optimized.