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Ticks Tick Borne Dis. 2017 Oct;8(6):837-849. doi: 10.1016/j.ttbdis.2017.06.010. Epub 2017 Jul 1.

Bioassays to evaluate non-contact spatial repellency, contact irritancy, and acute toxicity of permethrin-treated clothing against nymphal Ixodes scapularis ticks.

Author information

1
Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO, 80521, United States. Electronic address: evp4@cdc.gov.
2
Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO, 80521, United States.
3
Department of Biological & Environmental Sciences, Western Connecticut State University, 181 White Street, Danbury, CT, 06810, United States.

Abstract

Summer-weight clothing articles impregnated with permethrin are available as a personal protective measure against human-biting ticks in the United States. However, very few studies have addressed the impact of contact with summer-weight permethrin-treated textiles on tick vigor and behavior. Our aim was to generate new knowledge of how permethrin-treated textiles impact nymphal Ixodes scapularis ticks, the primary vectors in the eastern United States of the causative agents of Lyme disease, human anaplasmosis, and human babesiosis. We developed a series of bioassays designed to: (i) clarify whether permethrin-treated textiles impact ticks through non-contact spatial repellency or contact irritancy; (ii) evaluate the ability of ticks to remain in contact with vertically oriented permethrin-treated textiles, mimicking contact with treated clothing on arms or legs; and (iii) determine the impact of timed exposure to permethrin-treated textiles on the ability of ticks to move and orient toward a human finger stimulus, thus demonstrating normal behavior. Our results indicate that permethrin-treated textiles provide minimal non-contact spatial repellency but strong contact irritancy against ticks, manifesting as a "hot-foot" effect and resulting in ticks actively dislodging from contact with vertically oriented treated textile. Preliminary data suggest that the contact irritancy hot-foot response may be weaker for field-collected nymphs as compared with laboratory-reared nymphs placed upon permethrin-treated textile. We also demonstrate that contact with permethrin-treated textiles negatively impacts the vigor and behavior of nymphal ticks for >24h, with outcomes ranging from complete lack of movement to impaired movement and unwillingness of ticks displaying normal movement to ascend onto a human finger. The protective effect of summer-weight permethrin-treated clothing against tick bites merits further study.

KEYWORDS:

Bioassay; Contact irritancy; Ixodes scapularis; Permethrin-treated clothing; Toxicity

PMID:
28754599
PMCID:
PMC5665650
DOI:
10.1016/j.ttbdis.2017.06.010
[Indexed for MEDLINE]
Free PMC Article

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