Wash durability and optimal drying regimen of four brands of long-lasting insecticide-treated nets after repeated washing under tropical conditions

Malaria Journal

Research

Ayub V Ofulla¹  John M Vulule²  Stephen O Munga²  Francis K Atieli² 

[1] Department of Biomedical Sciences, Maseno University, Kenya;Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya;

关键词: Direct Sunlight;    Hand Rubbing;    Local Village;    High Performance Liquid Chromatography Grade;    Mosquito Mortality;   

DOI  :  10.1186/1475-2875-9-248

 received in 2010-04-28, accepted in 2010-08-30,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe current study was undertaken to determine the optimal wash-drying regimen and the effects of different washing procedures on the efficacy, and durability of four brands of newly introduced long-lasting insecticide-treated nets (LLINs) under tropical conditions.MethodsIn the current study, the following four LLINs were tested: Olyset®, PermaNet ®2.0, BASF® and TNT®. Nets were divided into three sets; one set was washed by hand rubbing and air-dried either hanging or spread on the ground in direct sunlight or hanging or spread on the ground under the shade. A second set was washed using the WHO protocol (machine) and the third set was washed by beating the nets on rocks. The biological activities of the nets were assessed by a three-minute bioassay cone test and the residual insecticide contents were determined using high performance liquid chromatography (HPLC) procedure.ResultsNets that were dried hanging under the shade retained more insecticide, 62.5% and recorded higher mortality compared to nets which were dried lying on the ground in direct sunlight 58.8%, nets dried under the shade spread on the ground 56.3%, and 57.8% for nets dried hanging in direct sunlight. It was also observed that nets washed by the standard WHO protocol, retained more insecticide and were more effective in killing mosquitoes compared to nets washed by local methods of hand rubbing and beating on rocks. There were significant differences between drying regimens (p < 0.0001) and between washing procedures (p < 0.001) respectively. However, the effect of net type was statistically insignificant. The statistical differences on individual nets were also compared, for PermaNet® and TNT there were no significant differences observed between the four drying regimens (p = 0.7944 and 0.4703) respectively). For BASF and Olyset, the differences were significant (p < 0.001 and p > 0.0001).ConclusionThe results of this study suggest that washing and drying regimen influence the insecticidal activity of LLINs. The standard WHOPES washing protocol underestimates the amount of insecticide washed from LLINs compared to the abrasive washing procedures that are used in the field. This suggests that there is need to educate net users to adopt a more gentle washing procedure while handling LLINs. The education should accompany net distribution campaigns.

【 授权许可】

CC BY   
© Atieli et al; licensee BioMed Central Ltd. 2010