Preventing tick attachment to dogs using essential oils

Preventing tick bites using repellents could make a valuable contribution to an integrated tick management programme for dogs. Here, the ability of a range of essential oils or active ingredients of commercially available repellents, to abolish the orientation and taxis of the tick Ixodes ricinus towards sebum extracted from dog hair was examined in laboratory bioassays. Substantial differences between oils were observed, but turmeric oil was both able to prevent a climbing response by ticks and had a longer residual activity than other oils. A blanket-drag field assay was then used to compare the attachment of ticks to blankets impregnated with one of: turmeric oil, DEET (positive control), orange-oil or excipient only (negative controls). In total, 899 ticks were counted, with an average of 23.3 (SD ± 21.3) ticks per blanket drag for excipient-only (n = 16), 26.9 (SD ± 28.6) for orange oil (n = 16), 2.6 (SD ± 2.0) for turmeric oil (n = 16) and 3.4 (SD ± 3.7) for DEET (n = 16). Finally, in a participatory in vivo trial, tick acquisition by 15 untreated control dogs was compared with 24 dogs sprayed with turmeric-oil and 16 dogs sprayed with orange oil (both 2.5% v/v diluted in water with a 1% coco glucoside excipient) before each walk in known tick infested areas. The percentage of dogs with ticks attached to the legs or belly of dogs sprayed with turmeric oil suspension (15% ± 19.4%) was significantly lower than that of ticks attached to the same areas of dogs sprayed with orange oil suspension (85% ± 19.4%) and unsprayed dogs (73% ± 26.2%) (P < 0.05). The data indicate that turmeric-oil may form a valuable component of a tick management programme for domestic dogs.