1. Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
2. National Centre for Animal and Plant Health (CENSA), San José de las Lajas, Mayabeque, Cuba.
3. Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland.
4. Provincial Centre of Hygiene, Epidemiology and Microbiology, Matanzas, Cuba.