Greyeyes,

I think you have missed the point. Airborne transmission is an accepted vector. I can only go by what is on the news and the MAFF site but my understanding is that the epidemiology of the current outbreak can trace those sites which have not had any direct contact with known carriers to confirmed sites given the wind, humidity, and temperature prevailing during the critical period.

Given that the last major outbreak in the UK is thought to have originated from the continent by airborn virus, any animal 30 miles downwind of an infected site has to be considered as being at risk.

Pete M