Permethrin treated clothing to protect outdoor workers: evaluation of different methods for mosquito exposure against populations with differing resistance status

Abstract

Minimizing arthropod exposure (e.g. mosquito and tick bites) is vital to protect health of outdoor workers. Personal protective measures can help protect against exposure. Here, the quantity of permethrin was evaluated for different fabric types after washing. Cone and petri dish exposure assays were used to investigate the knockdown/mortality of permethrin-susceptible and permethrin-resistant populations of mosquitoes. Permethrin-treated clothing was effective against the tested mosquito population that was susceptible to permethrin but not a permethrin-resistant population. Permethrin quantity was significantly highest in the 100% cotton fabric and for the 0 wash group. Permethrin quantity in fabrics decreased with washing. No significant differences (p > 0.05) were observed in knockdown/mortality rates for either exposure method. The protective effect of permethrin-treated clothing against mosquitoes is impacted by many factors, e.g. wash frequency, fabric type, and the susceptibility/resistance status of local mosquito populations.

Malaria Outbreak Facilitated by Appearance of Vector-Breeding Sites after Heavy Rainfall and Inadequate Preventive Measures: Nwoya District, Northern Uganda, February–May 2018

“…Wearing clothes that are long enough to cover arms and legs and stockings to cover feet can provide significant protection against malaria in the evenings, as our study findings indicate. Insecticidetreated clothing has also been provided to outdoor workers in various setting to protect them against mosquito bites [41,42]. In a study in Nigeria, protective clothing given to children under 5 years was reported to increase protection against malaria infection and anemia status [43].…”

Failure of Permethrin-Treated Military Uniforms to Protect Against a Laboratory-Maintained Knockdown-Resistant Strain of Aedes aegypti

“…They state that ''no mosquitoes were homozygous for kdr mutations at both SNPs,'' thus their ''resistant'' PR strain was not analogous to the PR strain used in this study or in Agramonte and, as they also noted, was possibly more susceptible than assumed. This demonstrates the importance of verifying the toxicology profile of strains used in comparative exposure tests, whether arm-in-cage studies with human volunteers or static assays (Agramonte et al 2017, Richards et al 2018, as a standard good laboratory practice.…”

Toxicity and persistence of permethrin‐impregnated clothing against the Australian paralysis tick, Ixodes holocyclus (Acari: Ixodidae)

“…In one study, even though unwashed LLPI 100% cotton fabrics had higher initial permethrin content than 50% cotton/50% polyester fabrics, the 100% cotton fabrics did not knockdown or kill any Aedes aegypti , while the 50% cotton/50% polyester had a knockdown and mortality rate of 2%, although this was not statistically higher (Richards et al . 2018). This study however indicated that the permethrin content in the 50% cotton/50% polyester fabric reduced by 63%, while the 100% cotton fabrics reduced by 70% after 15 washes.…”