title: The heat is on: Killing blacklegged ticks in residential washers and dryers to prevent tickborne diseases.
abstract: Reducing exposure to ticks can help prevent Lyme disease and other tickborne diseases. Although it is currently recommended to dry clothes on high heat for one hour to kill ticks on clothing after spending time outdoors, this recommendation is based on a single published study of tick survival under various washing conditions and a predetermined one-hour drying time. We conducted a series of tests to investigate the effects of temperature, humidity, and drying time on killing nymphal and adult blacklegged ticks (Ixodes scapularis). Muslin bags containing 5 ticks each were washed then dried or dried only with six cotton towels during each drying cycle. All nymphal and adult ticks were killed when exposed to wash cycles when the water temperature reached ≥54°C (≥130°F); however, 50% of ticks survived hot water washes when the water temperature was <54°C. The majority (94%) of ticks survived warm washes [temperature range, 27-46°C (80-115°F)] and all ticks survived cold washes [15-27°C (59-80°F)]. When subsequently dried on high heat setting [54-85°C (129-185°F)], it took 50min to kill all ticks (95% confidence limit, 55min). Most significantly, we found that all adult and nymphal ticks died when placed directly in the dryer with dry towels and dried for 4min on high heat (95% confidence limit, 6min). We have identified effective, easily implemented methods to rid clothing of ticks after spending time outdoors. Placing clothing directly in a dryer and drying for a minimum of 6min on high heat will effectively kill ticks on clothing. If clothing is soiled and requires washing first, our results indicate clothing should be washed with water temperature ≥54°C (≥130°F) to kill ticks. When practiced with other tick-bite prevention methods, these techniques could further reduce the risk of acquiring tickborne diseases.
authors.affiliation: Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA. Electronic address: wje1@cdc.gov.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Nelson
authors.affiliation: University of Vermont College of Medicine, Burlington, VT, USA.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Hayes
authors.affiliation: University of Vermont College of Medicine, Burlington, VT, USA.
authors.forename: Molly A
authors.initials: MA
authors.lastname: Markowitz
authors.affiliation: University of Massachusetts, Boston, MA, USA.
authors.forename: Jacqueline J
authors.initials: JJ
authors.lastname: Flynn
authors.affiliation: Vermont Agency of Agriculture, Barre, VT, USA.
authors.forename: Alan C
authors.initials: AC
authors.lastname: Graham
authors.affiliation: Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Delorey
authors.affiliation: Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Mead
authors.affiliation: Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA.
authors.forename: Marc C
authors.initials: MC
authors.lastname: Dolan
mesh_terms: D000818:Animals; D025065:Borrelia burgdorferi / Q000502:physiology; D003020:Clothing; D003080:Cold Temperature; D006358:Hot Temperature; D006813:Humidity; D018884:Ixodes / Q000382:microbiology; D008193:Lyme Disease / Q000382:microbiology / Q000517:prevention & control; D009758:Nymph / Q000382:microbiology / Q000502:physiology; D064927:Tick Bites / Q000382:microbiology; D017282:Tick-Borne Diseases / Q000382:microbiology / Q000517:prevention & control*; D014867:Water
chemical_list: D014867:Water
keywords: Borrelia burgdorferi; Clothing; Ixodes scapularis; Tick-borne disease prevention; Ticks