[1] Univ Laval, Fac Med, Dept Microbiol Infect Dis & Immunol, Quebec City, PQ G1K 7P4, Canada
[2] Brigham & Womens Hosp, Dept Med, Boston, MA 02115 USA
[3] Harvard Univ, Sch Med, Boston, MA USA
[4] Univ S Florida, Coll Med, Dept Mol Med, Tampa, FL USA
[5] HHV 6 Fdn, Santa Barbara, CA USA