Wild Card's description 
As an extreme, imagine if domestic dogs suddenly became a carrier for some flea-borne disease which affected humans in the UK. It would be a major issue. It is the equivalent of the Black Death, but instead of rats coming into the country you already have a huge dog population here. They are in very close human contact all the time and as a vector of disease, dogs would be quite dangerous. Is there something causing a change in fox behaviour? Because that it is so unlike a fox. Normally they don’t go into domestic dwellings, they are quite timid. They do feed off the contents of bins now and there is an upsurge in urban foxes, but there has been a change there. If foxes became a vector of disease or changed their behaviour to come into greater contact with humans, or if they cross-infected the dog population, then… imagine if people could not have dogs or cats in houses with them. If it was decided it was no longer safe for people to keep dogs as pets, then that would be a major wild card.