title: Permethrin-Treated Clothing as Protection against the Dengue Vector, Aedes aegypti: Extent and Duration of Protection.
abstract: BACKGROUND
  Dengue transmission by the mosquito vector, Aedes aegypti, occurs indoors and outdoors during the day. Personal protection of individuals, particularly when outside, is challenging. Here we assess the efficacy and durability of different types of insecticide-treated clothing on laboratory-reared Ae. aegypti.
  
  
  METHODS
  Standardised World Health Organisation Pesticide Evaluation Scheme (WHOPES) cone tests and arm-in-cage assays were used to assess knockdown (KD) and mortality of Ae. aegypti tested against factory-treated fabric, home-dipped fabric and microencapsulated fabric. Based on the testing of these three different treatment types, the most protective was selected for further analysis using arm-in cage assays with the effect of washing, ultra-violet light, and ironing investigated using high pressure liquid chromatography.
  
  
  RESULTS
  Efficacy varied between the microencapsulated and factory dipped fabrics in cone testing. Factory-dipped clothing showed the greatest effect on KD (3 min 38.1%; 1 hour 96.5%) and mortality (97.1%) with no significant difference between this and the factory dipped school uniforms. Factory-dipped clothing was therefore selected for further testing. Factory dipped clothing provided 59% (95% CI = 49.2%- 66.9%) reduction in landing and a 100% reduction in biting in arm-in-cage tests. Washing duration and technique had a significant effect, with insecticidal longevity shown to be greater with machine washing (LW50 = 33.4) compared to simulated hand washing (LW50 = 17.6). Ironing significantly reduced permethrin content after 1 week of simulated use, with a 96.7% decrease after 3 months although UV exposure did not reduce permethrin content within clothing significantly after 3 months simulated use.
  
  
  CONCLUSIONS
  Permethrin-treated clothing may be a promising intervention in reducing dengue transmission. However, our findings also suggest that clothing may provide only short-term protection due to the effect of washing and ironing, highlighting the need for improved fabric treatment techniques.
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: DeRaedt Banks
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom; arctec, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Orsborne
authors.affiliation: SFRC, University of Florida, Gainesville, Florida, United States of America.
authors.forename: Salvador A
authors.initials: SA
authors.lastname: Gezan
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Harparkash
authors.initials: H
authors.lastname: Kaur
authors.affiliation: Department of Global Health and Epidemiology, Umea University, Umea, Sweden; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
authors.forename: Annelies
authors.initials: A
authors.lastname: Wilder-Smith
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, Durham, United Kingdom.
authors.forename: Steve W
authors.initials: SW
authors.lastname: Lindsey
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom; arctec, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: James G
authors.initials: JG
authors.lastname: Logan
mesh_terms: D000330:Aedes; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003020:Clothing; D003715:Dengue / Q000517:prevention & control*; D005260:Female; D007302:Insect Repellents / Q000494:pharmacology; D007303:Insect Vectors; D007306:Insecticides / Q000494:pharmacology*; D026023:Permethrin / Q000494:pharmacology*; D014944:World Health Organization
chemical_list: D007302:Insect Repellents; D007306:Insecticides; D026023:Permethrin