1. Charité-Universitätsmedizin Berlin, Institute of Virology, Berlin, Germany
2. Universitätsklinikum Erlangen, Institute of Clinical and Molecular Virology, Erlangen, Germany
3. FRC Fundamentals of Biotechnology, Russian Academy of Science, Moscow, Russia
4. Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Griefswald, Germany