[1] Med Univ Lubeck, Inst Med Mol Biol, D-23538 Lubeck, Germany
[2] MP Chumakov Inst Poliomyelitis, Moscow, Russia
[3] Viral Encephalitides Acad Med Sci, Moscow, Russia
[4] Ist Super Sanita, I-00161 Rome, Italy
[5] Univ Munich, Max Von Pettenkofer Inst, Munich, Germany