[1] Bernhard Nocht Inst Trop Med, Dept Virol, D-20359 Hamburg, Germany
[2] Bernhard Nocht Inst Trop Med, Clin Dept, D-20359 Hamburg, Germany
[3] Humboldt Univ, Charite, Inst Virol, Berlin, Germany
[4] Red Cross Transfus Serv Hesse, Inst Transfus Med & Immunohematol, Frankfurt, Germany