We used to spray our uniforms with a permethrin based spray, it would kill ticks for up to six months (washing uniforms normally). Same stuff your vet uses on his/her lab coat.

Permethrin kills (especially fish and cats), DEET repels. We used both.
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Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein