Institute of Molecular Virology, Ulm University Medical Center, Institute of Molecular Virology, Ulm University Medical Center, Department of Molecular and Medical Virology, Ruhr University Bochum, Ruhr University of Bochum - Department of Molecular & Medical Virology, Department of Infectious Diseases, West German Centre of Infectious Diseases, University Hospital Essen, University of Duisburg-Essen, University of Duisburg-Essen - Institute for Virology, Institute for Microbiology and Hygiene, Ulm University Medical Center, Institute of Molecular Virology, Ulm University Medical Center, Ruhr University of Bochum - Department of Molecular & Medical Virology, Institute of Molecular Virology, Ulm University Medical Center and Department of Molecular and Medical Virology, Ruhr University Bochum