Long lasting insecticidal nets use, efficacy and physical integrity in a vector resistance area after a nationwide campaign in southern Benin, West Africa

Abstract

Although effective malaria control measures such as long lasting insecticidal nets (LLINs) have been promoted, relatively little is known about their coverage dimension. However, usage varies among households, and such variation may seriously limit the potential impact of nets. Moreover, the efficacy of these measures against Anopheles gambiae in some departments is unknown. The objective of this study was to investigate LLINs coverage and use, and their efficacy against A. gambiae in Oueme department after a mass free distribution. A post survey campaign was undertaken in January, 2012 to assess the effect of campaign six months after LLINs (Olyset net) free distribution in southern Benin. A questionnaire has been provided to heads of 1,600 households randomly selected from four districts. Despite LLINs use reaching more than 80%, coverage was low at 50.9%. A considerable damage rate (14%) of Olyset nets after only 6 months of use was observed. Bioassays revealed inefficacy of olyset toward the local population of A. gambiae after only 6 months of use. Free distribution of LLINs rapidly improved their coverage in communities. The rapid wear observed associated with low efficacy raises the problem of the choice of impregnated materials in a context of high vector resistance to insecticides. Key words: Long lasting insecticidal nets (LLINs), olyset, efficacy, Anopheles gambiae, vector control.