1. Department of Pathology, Diakonissenkrankenhaus Flensburg, Flensburg, Germany
2. Department of Pathology, Center for Perinatal and Pregnancy-Related Pathology, Oslo University Hospital-Ullevål, Oslo, Norway
3. Department of Pathology, Hannover Medical School, Hannover, Germany
4. Department of Obstetrics and Gynecology, Diakonissenkrankenhaus Flensburg, Flensburg, Germany
5. Department of Virology, Hannover Medical School, Hannover, Germany