1. 1Field Service, National Infection Service, Public Health England, Liverpool, UK
2. 2Institute of Psychology, Health and Society, University of Liverpool, Liverpool, UK
3. 3NIHR Health Protection Research Unit in Gastrointestinal Infections, Liverpool, UK
4. 4North West Health Protection Team, Public Health England, Liverpool, UK
5. 5National Infection Service, Public Health England, London, UK
6. 6Royal Liverpool and Broadgreen University Hospitals NHS Trust, Liverpool, UK