Dr. Paul McKeown:

Taking the New Forest example, that testing regime showed that approximately one in four people was positive. The New Forest is in an area with a lot of ticks, deer and small mammals. As well as feeding on human blood, ticks have a varied diet and also feed on other blood. If in the New Forest roughly one in four people has a positive Lyme test, I do not know if it is possible to say everyone has been bitten but in areas like that a significant minority of people will be positive. In Dublin, where there would be lower tick populations, the figure would be 0.5% or 1%. Only a minority of people in Dublin would have been bitten. In the high endemicity areas it is a significant minority.