Small, 8-legged animals that feed on blood and sometimes transmit diseases to humans via their bites. Ticks are about 3 mm long before feeding and become larger when bloated with blood. Ticks may be picked up in long grass, scrub, woodland, or caves. In the UK, the only disease known to be transmitted to humans by ticks is Lyme disease. Others transmitted in various parts of the world include relapsing fever, Rocky Mountain spotted fever, Q fever, tularaemia, and certain types of viral encephalitis. The prolonged bite of certain female ticks can cause tick paralysis, in which a toxin in the tick saliva affects the nerves that control movement. In extreme cases, this can be fatal.
Ticks and disease |
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