1. Department of Microbiology, University of León, UNAN-León, Nicaragua
2. Division of Molecular Virology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
3. Microbiology, Tumor and Cell Biology Centre, Karolinska Institutet, S-171 77 Stockholm, Sweden
4. Division of Medical Microbiology, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden