[1] Royal Cornwall Hosp Trust, Cornwall Gastrointestinal Unit, Truro TR1 3LJ, Cornwall, England
[2] Peninsula Coll Med & Dent, Truro, England
[3] Royal Devon & Exeter Hosp, Dept Gastroenterol, Exeter EX2 5DW, Devon, England
[4] Derriford Hosp, Dept Gastroenterol, Plymouth PL6 8DH, Devon, England
[5] Torbay Hosp, Dept Gastroenterol, Torquay, England
[6] Hlth Protect Agcy, Ctr Infect, Virus Reference Dept, London, England
[7] Royal Cornwall Hosp Trust, Clin Microbiol, Truro, England