[1] Charite Sch Med, Berlin, Germany
[2] Chumakov Inst Poliomyelitis & Viral Encephalitide, Moscow, Russia
[3] Med State Univ, Samara, Russia
[4] Antiplague Stn, Soci, Russia
[5] Antiplague Stn, Novorossiysk, Russia
[6] Slovak Acad Sci, Bratislava, Slovakia