Decreased bioefficacy of long-lasting insecticidal nets and the resurgence of malaria in Papua New Guinea

Papua New Guinea (PNG) has the highest malaria transmission outside of Africa. Long-lasting insecticidal nets (LLINs) are believed to have helped to reduce average malaria prevalence in PNG from 15.7% in 2008 to 1% in 2014. Since 2015 malaria indicators in PNG have risen significantly. In the present study, we observed a drastically decreased bioefficacy of unused LLINs with manufacturing dates between 2013 and 2019 collected from villages and LLIN distributors in PNG. Specifically, of the tested n=167 LLINs manufactured between 2013 and 2019 only 16% achieved ≥ 80% 24h-mortality or ≥ 95% 60 min-knockdown in cone bioassays conducted with pyrethroid susceptible Anopheles farauti mosquitoes. In contrast, all (100%, n=25) LLINs with manufacturing dates between 2007 and 2012 achieved ≥ 80% 24h-mortality or ≥ 95% 60 min-knockdown. This difference was extremely statistically significant. We hypothesise that decreased bioefficacy of LLINs has contributed to the malaria resurgence in PNG.

Methods
This dataset is the result of cone bioassays on unused and used long-lasting insecticidal nets using Anopheles farauti mosquitoes. The assays were conducted at the Papua New Guinea Institute of Medical Research. Please refer to the manuscript methods section for detailed information on the methods employed in this study. Data are presented in the form of an excel spreadsheet.