n. a bloodsucking parasite belonging to the order of arthropods (the Acarina) that also includes the *mites. Tick bites can cause serious skin lesions and occasionally paralysis (see Ixodes; Amblyomma), and certain tick species transmit *typhus, *Lyme disease, and *relapsing fever. Diethyltoluamide (DEET) is used as a tick repellent. There are two families: Argasidae (soft ticks), which includes Ornithodoros, with mouthparts invisible from above and no hard shield (scutum) on the dorsal surface; and Ixodidae (hard ticks), including Dermacentor, Haemaphysalis, and Rhipicephalus, with clearly visible mouthparts and a definite scutum.