[1] McGill Univ, Dept Oncol, Montreal, PQ H2W 1S6, Canada
[2] McGill Univ, Dept Epidemiol & Biostat, Montreal, PQ H2W 1S6, Canada
[3] McGill Univ, Dept Surg, Montreal, PQ H2W 1S6, Canada
[4] McGill Univ, Dept Pathol, Montreal, PQ H2W 1S6, Canada
[5] McGill Univ, Dept Obstet & Gynecol, Montreal, PQ H2W 1S6, Canada
[6] McGill Univ, Jewish Gen Hosp, Dept Pathol, Montreal, PQ H3T 1E2, Canada
[7] Ctr Hosp Univ Montreal, Dept Microbiol & Infectiol, Montreal, PQ H2L 4M1, Canada
[8] Univ Manitoba, Dept Community Hlth Sci, Winnipeg, MB R3E 0W3, Canada