Per head of population, more cases of human illness from infection with Shiga toxin producing E. coli (STECs) occur in Scotland than elsewhere in the United Kingdom. We will use detailed information from whole-genome sequences to improve knowledge of STEC that exist in the ecosystems of Scottish dairy cattle, sheep, farmed deer and leafy produce. We will compare them with sequenced isolates from Scottish human cases, to help develop ways to reduce the burden of disease in the Scottish human population. We will also investigate if current laboratory diagnostic detection methods can be improved, which would save time and money.