I seem to recall the story surrounding one plague in Europe. As told,
or written, the cats were blamed for the sickness (achoo achoo we all
fall down) carried by rodents. The cats were slaughtered in a belief
that they were the disease vector, which, in what might be described
as only a human weakness, led to increasing vermin levels and the
incidence of plague victims. I think it is from the epidemiological
literature (the "tea pump" case the more famous one).

George Myers