1. Doctoral students, professor, and associate professor, respectively, Department of Biochemistry, Royal Institute of Technology, Teknikringen 34 S-100 44 Stockholm, SE.
2. Doctoral student, The National Laboratory of Forensic Science, S-581 94 Linköping, SE.
3. Post doctoral student, Department of Clinical Virology, Swedish Institute for Infectious Disease Control, S-105 21 Stockholm, SE.