Permethrin-impregnated curtains against phlebotomine sandflies (Diptera: Psychodidae): laboratory and field studies.

The efficacy of permethrin-impregnated nets against vectors of leishmaniases was evaluated in laboratory and field studies. Permethrin-impregnated curtains were tested at different dosages in experimental tunnel against Phlebotomus perniciosus and P. papatasi. The influence on feeding behaviour and the mortality rate post contact with the impregnated curtain were investigated. The vapour effect of permethrin on P. perniciosus adults confined less than 1 cm away from a treated net was also evaluated. From laboratory studies it seems that permethrin shows low or any barrier effect against sandfly species tested, and that the high insecticidal activity (mortality rate greater than 90%, 24 hours after the contact with treated net, 1 g/m2) and the reduction of biting rate observed (between 53.56% and 85.24%) are the main effects that make permethrin-impregnated nets very effective for sandfly control. In field studies carried out in cutaneous leishmaniasis foci of Italy, it was demonstrated that permethrin-impregnated curtains around windows and around CDC light traps, reduce the number of sandflies entering the stables and traps. In Burkina Faso, indoor use of wide-mesh cotton curtains impregnated with permethrin 1 g/m2 almost completely eliminate the occurrence of endophilic sandfly species. In conclusion the use of permethrin-impregnated curtains could be an alternative to residual house-spraying for the control of endophilic vectors of leishmaniases.