Submitted to: Journal of Medical Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/13/2003
Publication Date: 3/17/2003
Citation: Carroll, J.F. 2003. A cautionary note: survival of nymphs of two species of tick (acari: ixodidae) among clothes laundered in an automatic washer. Journal of Medical Entomology. 40:732-736. Interpretive Summary: Tick-borne diseases are serious human health problems in parts of the U. S. Host-seeking ticks are often brought into homes on clothing worn by persons returning from tick infested habitats. Such ticks pose at least a temporary risk to people and pets in the house. Many persons perceive the risk to be over when the clothes are laundered. To ascertain whether typical laundering practices kill ticks on clothes, small polyester mesh packets containing host-seeking lone star tick, Amblyomma americanum, and blacklegged tick, Ixodes scapularis nymphs, were placed among clothing washed in cold, warm and hot water in a clothes washer. Ticks were also placed with the damp washed clothing in a clothes dryer for 1 h cycles at high heat and air only. Nearly all nymphs of both tick species survived the cold and warm washes. Most lone star ticks survived the hot wash, as did about half the blacklegged ticks. All the ticks that were subjected to the 1 h cycle of high heat in the dryer died, but some of both species survived the air only drying. These findings should improve public awareness of risks associated with laundering clothes potentially infested by ticks.
Technical Abstract: Host-seeking ticks often remain on clothing of persons returning home from work or recreation in tick habitats, and can pose at least a temporary risk to people and pets in these homes. Laundering clothing in automatic clothes washers gives people a sense that the washed garments are tick free. Host-seeking lone star tick, Amblyomma americanum (L.), and blacklegged tick, Ixodes scapularis Say, nymphs confined in polyester mesh packets, were included with laundry in cold, warm and hot wash cycles of an automatic clothes washer. Ticks were also placed with washed clothing and subjected to drying in an automatic clothes dryer set on high heat. Most nymphs (¿90%) of both species survived the cold and warm washes, and 95% of A. americanum nymphs survived the hot wash. At the time of their removal from the washer, I. scapularis nymphs were clearly affected by the hot wash, but 65% were considered alive 20 - 24 h later. All ticks were killed by the 1 h cycle at high heat in the clothes dryer, but with unheated air some nymphs of both species survived the 1 h cycle in the dryer. Given the laundering recommendations of clothing manufacturers and variation in the use automatic clothes washers, laundry washed in automatic washers should not be considered free of living ticks.