Optimising sleep quality inside insecticide treated mosquito nets in hot overnight environments

Approximately half of the world’s population is at risk of contracting malaria, a parasitic infection that is transmitted by the Anopheles mosquito. In 2020, malaria infections were responsible for 240 million infections and 627, 000 deaths, with 95% of these occurring in the African region. The mass distribution of insecticide-treated bed netting (ITN) have been a key initiative to successfully reduced malaria transmission, with over 1.5 billion nets distributed free-of-charge since 2008. However, non-adherence to ITNs remains a significant issue, with only 5 countries in the African region achieving the target of 80% usage of ITNs in 2020. The primary barrier to ITN use are that conditions are too hot to sleep comfortably. Studies of real-living conditions and wind tunnel experiments have shown that bed-netting significantly attenuates airflow by up to 75%, without affecting temperature or humidity within the enclosure. Thus, the sensations of feeling too hot are driven by reductions in airflow. While the use of an electric fan that is integrated into the net could improve sleeping conditions by increasing airflow, public health agencies (including the World Health Organisation) state that fans should be turned off above 32-35˚C due to concerns of exacerbating the risk of dehydration and heat illness, despite no evidence to support this recommendation. Thus, the efficacy and safety of using overnight fan use in conditions where malaria is endemic remains unknown. Using a climate chamber, will systematically test a range of air velocities across nine different combinations of air temperature and humidity that simulate typical overnight conditions in the African region. In this way, our project will determine the minimum air velocity required to improve sleep quality without exacerbating the risk of dehydration or heat stress, and how this air velocity changes as a function of higher air temperature or humidity.