Mere contact with such an area will suffice, the inbreeding is not obligatory. I lived on the fringes of the Fens for many years (and a short time amingst them)and I am now diabetic, although my eyes are a reasonable distance apart and my feet haven't adapted themselves for walking on boggy ground (the toes are still seperate).

Retires in hail of sugar beet and brussel sprouts.