1. Faculty of Veterinary Medicine; Institute of Veterinary Anatomy; University of Leipzig; An den Tierkliniken 43 04103 Leipzig Germany
2. Department of Veterinary Medicine; Institute of Veterinary Anatomy; Freie Universität Berlin; Koserstr. 20, 14195 Berlin Germany
3. Department of Internal Medicine; HIV Translational Research Unit; Ghent University Hospital; De Pintelaan 185, 9000 Ghent Belgium