[1] Glasgow Royal Infirm, Glasgow G4 0SF, Lanark, Scotland
[2] Hlth Protect Agcy, Med Affairs & Special Pathogens Reference Lab, Salisbury SP4 0JG, Wilts, England
[3] Umea Univ, Dept Integrat Med Biol, Sect Anat, Umea, Sweden
[4] Univ Glasgow, Ctr Cell Engn, Fac Biol & Life Sci, Glasgow, Lanark, Scotland