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Permethrin-Treated Clothing as Protection against the Dengue Vector, Aedes aegypti: Extent and Duration of Protection.

DeRaedt Banks S, Orsborne J, Gezan SA, Kaur H, Wilder-Smith A, Lindsey SW, Logan JG - PLoS Negl Trop Dis (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom.

ABSTRACT

Introduction: 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.

Conclusion: 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.

No MeSH data available.


Related in: MedlinePlus

Permethrin content (mg/cm2) of WHO bottle and machine washed materials at 0, 1, 5, 10, 15, 20, 25 & 30 washes.Whiskers correspond to 95% confidence intervals.
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pntd.0004109.g004: Permethrin content (mg/cm2) of WHO bottle and machine washed materials at 0, 1, 5, 10, 15, 20, 25 & 30 washes.Whiskers correspond to 95% confidence intervals.

Mentions: The HPLC analysis performed on factory dipped (FDC) clothing demonstrated that the concentration of permethrin on treated clothing decreased with washing. For the WHO washing technique, permethrin concentration decreased from 0.317 mg/cm2 for unwashed clothing to 0.186 mg/cm2 after five washes (p<0.0001 a 41.3% decrease) (Fig 4), and to a concentration of 0.009 mg/cm2 after 30 washes (p<0.0001 a decrease of 97.2%). The machine washing technique produced a decrease from 0.397 mg/cm2 to 0.286 mg/cm2 after five washes (p<0.0001, a decrease of 28%) with 0.073 mg/cm2 of permethrin present after 30 washes (a decrease of 81.6%) (Fig 4).


Permethrin-Treated Clothing as Protection against the Dengue Vector, Aedes aegypti: Extent and Duration of Protection.

DeRaedt Banks S, Orsborne J, Gezan SA, Kaur H, Wilder-Smith A, Lindsey SW, Logan JG - PLoS Negl Trop Dis (2015)

Permethrin content (mg/cm2) of WHO bottle and machine washed materials at 0, 1, 5, 10, 15, 20, 25 & 30 washes.Whiskers correspond to 95% confidence intervals.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595206&req=5

pntd.0004109.g004: Permethrin content (mg/cm2) of WHO bottle and machine washed materials at 0, 1, 5, 10, 15, 20, 25 & 30 washes.Whiskers correspond to 95% confidence intervals.
Mentions: The HPLC analysis performed on factory dipped (FDC) clothing demonstrated that the concentration of permethrin on treated clothing decreased with washing. For the WHO washing technique, permethrin concentration decreased from 0.317 mg/cm2 for unwashed clothing to 0.186 mg/cm2 after five washes (p<0.0001 a 41.3% decrease) (Fig 4), and to a concentration of 0.009 mg/cm2 after 30 washes (p<0.0001 a decrease of 97.2%). The machine washing technique produced a decrease from 0.397 mg/cm2 to 0.286 mg/cm2 after five washes (p<0.0001, a decrease of 28%) with 0.073 mg/cm2 of permethrin present after 30 washes (a decrease of 81.6%) (Fig 4).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom.

ABSTRACT

Introduction: 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.

Conclusion: 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.

No MeSH data available.


Related in: MedlinePlus