In spite of increasing vector resistance against pyrethroid insecticides and the acknowledged need to address residual transmission, insecticide treated nets remain the core element of malaria vector control in most endemic countries.
This success was possible by the introduction of the long-lasting insecticidal net (LLIN) technology some 20 years ago and the commitment of governments and donors to provide huge numbers of free LLIN to achieve and sustain universal coverage with LLIN. While the need to monitor the quality and field performance of LLIN products with respect to physical and insecticidal durability has long been established, results from operations research has at times been inconsistent or even misleading due to the lack of a comprehensive and standardized methodology for the physical durability of nets. This has changed with the release in 2013 of WHO guidance for estimating LLIN physical durability using a single, standardized metric that allows comparison of results between countries and at different time points.
The VectorWorks project has been monitoring LLIN durability as part of the U.S. President’s Malaria Initiative in seven countries applying a standardized methodology based on the latest recommendations from WHO and building in-country capacity for future durability monitoring activities. Different brands of LLIN were followed up in prospective cohort studies for up to three years looking at two principal scenarios: either comparing two different brands of LLIN in very similar ecological and socio-behavioral settings, or comparing the same brand of LLIN in different parts of a country where varying durability performance is expected due to differences in environmental and/or cultural or behavioral differences.
The results from each country provide valuable information for the Malaria Control or Elimination Program management teams, but also allow significant learnings from cross-country comparisons and pooled data analysis.
This series comprehensively summarizes the work done within the VectorWorks project and is hoped to contribute to a better understanding of drivers of physical and insecticidal durability of LLIN.
Edited by: Joshua Yukich, Tulane University, USA