Elevated Temperature Decreases the Insecticidal Efficacy of Yahe LN Insecticide-Treated Nets: Implications for Transport and Storage

A recent durability study has revealed that Yahe LN® insecticide-treated nets (ITNs; Fujian Yamei Industry & Trade Co., LTD, Fuzhou, China) distributed in Papua New Guinea (PNG) in 2021 did not retain their insecticidal efficacy after several months post-distribution. Insecticide-treated nets are frequently shipped and stored in containers where they are exposed to elevated temperatures. When used in the tropics, ITNs may continue to be exposed to high ambient temperatures. The aim for the present study is to better understand the potential impact of elevated temperature during transport and storage on the insecticidal efficacy of Yahe LN ITNs and to investigate why they failed insecticidal efficacy tests after 6 months in PNG. To achieve this aim, Yahe ITNs were stored at elevated temperatures and tested using cone bioassays. The results revealed that ITNs exposed to temperatures between 35°C and 50°C, reflective of those in shipping containers, exhibited a significantly decreased insecticidal efficacy. The present study highlights the importance of developing temperature-stable ITN products and assessing current products for temperature stability.