RESEARCH vised handwashing before and after eating should be rein- forced at the point of selling food. Our findings, and those of others (4,5,7,12,13) also suggest that calves may not be suitable animals for petting. In addition, we recommend specifically that food, particularly sweet and sticky food, only be sold and eaten in clean areas of the farm. Ideally, such sticky foods should be discouraged altogether. Acknowledgments We thank staff at the Anglesey County Council, North Wales Health Authority, and Public Health Laboratory Service Communicable Disease Surveillance Centre (Wales) for their support in investigating this outbreak, in particular, Sue Williams and Sue Davies. Dr. Payne is director of public health at South Gloucestershire Primary Care Trust, a U.K. National Health Service organization responsible for providing community and primary care, commissioning hospital care, and working with partner organizations to improve population health and reduce health inequalities. References 1. Willshaw GA, Cheasty T, Smith HR, O’Brien SJ, Adak GK. Verocytotoxin-producing Escherichia coli (VTEC) O157 and other VTEC from human infections in England and Wales: 1995–1998. J Med Microbiol 2001;50:135–42. 2. Dawson A, Griffin R, Fleetwood ABNJ. Farm visits and zoonoses. Commun Dis Rep 1995;5:R81–6. 3. Two outbreaks of Vero cytotoxin producing Escherichia coli O157 infection associated with farms. Commun Dis Rep CDR Weekly 1997;7:263,266. 4. Public Health Laboratory Service. Escherichia coli O157 general out- breaks. Available from: URL:http://www.phls.co.uk/facts/ecolit4.htm (accessed June 20,1999). 5. Shukla R, Slack R, George A, Cheasty T, Rowe B, Scutter J. Escherichia coli O157 infection associated with a farm visitor centre. Commun Dis Rep 1995;5:R86–90. 6. Milne LM, Plom A, Strudley I, Pritchard GC, Crooks R, Hall M, et al. Escherichia coli O157 incident associated with a farm open to members of the public. Commun Dis Public Health 1999;2:22–6. 7. Trevena WB, Willshaw GA, Cheasty T, Wray C, Gallagher J. Vero cytotoxin–producing E coli O157 infection associated with farms. Lancet 1996;347:60–1. 8. Parry SM, Salmon RL, Willshaw GA, Cheasty T, Lund LJ, Wearden P, et al. Haemorrhagic colitis in child after visit to farm visitor centre. Lancet 1995;346:572. 9. Health and Safety Executive. Avoiding ill health at open farms— advice to farmers (with teachers’ supplement). Agricultural Information Sheet No 23 (revised). London: Health and Safety Executive; 2000. 10. Thomas A, Cheasty T, Frost JA, Chart H, Smith HR, Rowe B. Verocytotoxin-producing Escherichia coli, particularly serogroup O157, associated with human infections in England and Wales: 1992–4. Epidemiol Infect 1996;117:1–10. 11. Willshaw GA, Smith HR, Cheasty T, Wall PG, Rowe B. Vero cytotox- in–producing Escherichia coli O157 outbreaks in England and Wales, 1995: phenotypic methods and genotypic subtyping. Emerg Infect Dis 1997;3:561–5. 12. Gage R, Crielly A, Baysinger M, Chernak E, Herbert G, Johnson- Entsuah A, et al. Outbreaks of Escherichia coli O157:H7 infections among children associated with farm visits—Pennsylvania and Washington, 2000. MMWR Morb Mortal Wkly Rep 2001;50:293–7. 13. Richards MS, Corkish JD, Sayers AR, McLaren IM, Evans SJ, Wray C. Studies of the presence of verocytotoxic Escherichia coli O157 in bovine faeces submitted for diagnostic purposes in England and Wales and on beef carcasses in abattoirs in the United Kingdom. Epidemiol Infect 1998:120;187–92. 14. Subcommittee of the PHLS Advisory Committee on Gastrointestinal Infections. Guidelines for the control of infection with Vero cytotox- in producing Escherichia coli (VTEC). Commun Dis Public Health 2000;3:14–23. Address for correspondence: Christopher Payne, Director of Public Health, South Gloucestershire Primary Care Trust, Monarch Court, Emerson's Green, South Gloucestershire, England BS16 7FH; fax: 44- 117-330-2401; email: chris_payne@btinternet.com Use of trade names is for identification only and does not imply endorsement by the Public Health Service or by the U.S. Department of Health and Human Services. 530 Emerging Infectious Diseases • Vol. 9, No. 5, May 2003