Tick paralysis

Tick paralysis is a disease caused when a tick attaches itself to a human and starts releasing toxic saliva into the bloodstream. The saliva poisons the nerves resulting in muscle weakness and paralysis, generally starting in the lower extremities and moving upwards. It can be caused by any type of tick and usually affects people in the United States during the summer as ticks become active. The tick's saliva continues to increase in volume the longer the tick is attached and peaks at about one week after the tick attaches itself.
Once the tick is removed, the symptoms will resolve themselves, often within hours. However, the symptoms are similar to Guillain-Barre syndrome and Botulism and the disease is often mistaken for these illnesses.
The only prevention for the illness is to avoid areas where ticks or common, or to wear clothing covering the entire body in areas where ticks are known to exist.
Tick paralysis at Wikipedia