1. Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, Copenhagen E 2100, Denmark
2. Laboratoire de Physique, Ecole Normale Superieure, Rue Lhomond 15, Paris 07505, France
3. Infektionsberedskab, Statens Serum Institute, Artillerivej, Copenhagen S 2300, Denmark
4. DTU Compute, Section for Dynamical Systems, Department of Applied Mathematics and Computer Science, Technical University of Denmark, Anker Engelunds Vej 101A, Kongens Lyngby 2800, Denmark
5. Animal Welfare and Disease Control, University of Copenhagen, Gronnegårdsvej 8, Frederiksberg C 1870, Denmark