The first known case of Lyme Disease has been contracted on the Mendip Hills in Somerset.
The tick bites humans before feeding on their blood.
The disease is caused by ticks, which can bring on arthritis, nerve and heart problems. It is transmitted to humans through bites.
Andrew Tinknell, of Congresbury, was out running on the hills when he was bitten by a tick.
He told the BBC: "It was only when the rash came out that I thought I'd better go and see the doctor about it."
The ticks bite humans in order to feed on their blood.
They hide in shady, moist, leaf litter, but also cling to tall grass, shrubs and low tree branches, waiting for an animal to brush against them so they can climb on board.
Ticks can attach themselves almost anywhere on the body, but prefer creases like the armpit, groin, or back of knee.
In the US, where the disease is more common, the Borrelia burgdorferi bacteria causes the disease.