[1] Alfred Hosp, Dept Infect Dis, Melbourne, Vic 3004, Australia
[2] Burnet Inst, Dept Neurovirol, Melbourne, Vic, Australia
[3] Monash Univ, Dept Med, Clayton, Vic, Australia
[4] Salk Inst, San Diego, CA 92186 USA
[5] NIMH, NIH, Bethesda, MD 20892 USA
[6] Univ N Carolina, Dept Neurol, Chapel Hill, NC USA
[7] St Vincents Hosp, Dept Neurol, Sydney, NSW 2010, Australia
[8] Univ New S Wales, Dept Med, Sydney, NSW, Australia