Durability assessment results suggest a serviceable life of two, rather than three, years for the current long-lasting insecticidal (mosquito) net (LLIN) intervention in Benin

BACKGROUND: LLIN distribution, every three years, is a key intervention of Benin's malaria control strategy. However, data from the field indicate that LLIN lifespan appears to vary based on both intrinsic (to the LLIN) and extrinsic factors. METHODS: We monitored two indicators of LLIN durability, survivorship and integrity, to validate the three-year-serviceable-life assumption. Interviews with net owners were used to identify factors associated with loss of integrity. RESULTS: Observed survivorship, after 18 months, was significantly less (p<0.0001) than predicted, based on the assumption that nets last three years. Instead, it was closer to predicted survivorship based on a two-year LLIN serviceable life assumption (p=0.03). Furthermore, the integrity of nearly one third of 'surviving' nets was so degraded that they were in need of replacement. Five factors: washing frequency, proximity to water for washing, location of kitchen, type of cooking fuel, and low net maintenance were associated with loss of fabric integrity. CONCLUSION: A two-year serviceable life for the current LLIN intervention in Benin would be a more realistic program assumption.