Perhaps the Caldwells of Yorkshire were wiped out because of their closeness to sheep.

Would there not be major risks of infection, such as anthrax, with sheep close to the shepherd's dwelling; contamination of manure in open barns and subsequent spread over nearby pastures; the frequent dry windy weather; contamination of walking surfaces with infected sheep placenta; spread of infection in densely settled area; and daily contact with the sheep flock or its shepherd?