RESUMO
Understanding and improving the durability of long-lasting insecticidal nets (LLINs)in the field is critical for the success of malaria prevention using mosquito nets,as well as contributing to procurement decisions based on the number of yearsof protection, rather than the current practice of unit cost. Using the recentlypublished guidelines from the World Health Organization (WHO) some progresshas been made in the monitoring and assessment of performance of nets in thefield. This paper describes the protocol of an ongoing retrospective study of theattrition rate, physical integrity and bioefficacy of three polyester LLIN productsthat were distributed during 2010 to 2013 in Nepal. It is hoped that robust andauditable data on net survival (physical integrity and bioefficacy) of these threebrands in different environments will assist the Nepal National Malaria ControlProgramme in planning future LLIN-replacement strategies, including behaviourchange communication about LLIN care and maintenance. The advantages anddisadvantages of prospective and retrospective cross-sectional approachesare discussed, including appropriate strategies to validate the timing for massdistribution of nets. Similar studies should be done in other countries to (i) trackLLIN durability to support management of resupply, and (ii) inform procurementdecisions at the global level. New, more predictive, textile laboratory testing is alsourgently needed.