Enterohaemorrhagic E. coli O157:H7 was first implicated in
human disease in the early 1980s, with the ruminants cited as
the primary reservoirs. Preliminary studies indicated cattle to be
the sole source of E. coli O157:H7 outbreaks in humans, however,
further, epidemiological studies have demonstrated that E. coli
O157:H7 was widespread in other food sources and that a number
of transmission routes existed.