[1] London Sch Hyg & Trop Med, Fac Infect & Trop Dis, London WC1E 7HT, England
[2] BC Womens Hosp, Vancouver, BC V6H 3N1, Canada
[3] Fac Med Creteil Paris Est, F-94010 Creteil, France
[4] Charite Univ Med Berlin, Inst Med Immunol, D-10117 Berlin, Germany
[5] Neurol & Stroke Unit Neurosci Dept ASST Lecco, I-23900 Merate, Italy
[6] Rikshosp OUS, Natl Advisory Unit CFS ME, Oslo Univ Hosp, N-0372 Oslo, Norway
[7] Univ Autonoma Barcelona, Chron Fatigue Unit, Hosp Univ Vall dHebron Univ Hosp VHIR, E-08035 Barcelona, Spain
[8] Titu Maiorescu Univ, Cent Mil Emergency Univ Hosp, Bucharest 040441, Romania
[9] Univ Oslo, Inst Hlth & Soc, Fac Med, Box 1089 Blindern, N-0317 Oslo, Norway
[10] Bragee ME CFS Ctr, S-11526 Stockholm, Sweden
[11] Tech Univ Munich, Sch Med, Dept Pediat, D-80333 Munich, Germany
[12] Privat Hosp Danmark, DK-2920 Charlottenlund, Denmark
[13] Charite, Inst Med Immunol, Dept Hematol Oncol & Tumor Immunol, D-10117 Berlin, Germany
[14] Univ Novi Sad, Med Fac Novi Sad, Novi Sad 21000, Serbia
[15] Univ Lisbon, Ctr Stat & Its Applicat, P-1749016 Lisbon, Portugal
[16] Erasmus MC Univ Med Ctr, NL-3015 Rotterdam, Netherlands
[17] Nicolaus Copernicus Univ Torun, Dept Hyg Epidemiol Ergon & Postgrad Educ, Coll Med, PL-85067 Bydgoszcz, Poland
[18] Buckinghamshire New Univ, Soc & Hlth, High Wycombe HP11 2JZ, Bucks, England
[19] Vall dHebron Hosp Res Inst VHIR, Div Rheumatol, ME CFS Res Unit Lab 009 Box 02, Val dHebron Hosp Res Unit VIHR, Passeig Val dHebron 119-129, E-08035 Barcelona, Spain
[20] Univ Thessaly, Dept PE & Sports Sci, Trikala 42100, Greece
[21] Univ Pavia, Dept Earth & Environm Sci, I-27100 Pavia, Italy
[22] Univ Hosp Southern Denmark, Dept Reg Hlth Res, DK-5000 Odense, Denmark
[23] Natl Univ Ireland Galway, Sch Business & Econ, Univ Rd, Galway H91 TK33, Ireland
[24] Riga Stradins Univ, Dept Infectiol & Dermatol, LV-1067 Riga, Latvia
[25] Uppsala Univ, Dept Chem Biomed Ctr, Analyt Chem & Neuro Chem, S-75123 Uppsala, Sweden
[26] Uppsala Univ, Myalg Encephalomyelitis Chron Fatigue Syndrome ME, S-75123 Uppsala, Sweden
[27] Riga Stradins Univ, Inst Microbiol & Virol, LV-1067 Riga, Latvia
[28] CFS ME Med Ctr, NL-1078 Amsterdam, Netherlands
[29] London Sch Hyg & Trop Med, Dept Clin Res, Fac Infect & Trop Dis, London WC1E 7HT, England