1. VISAVET Health Surveillance Centre, Universidad Complutense, 28040 Madrid, Spain
2. Department of Animal Health, Faculty of Veterinary Medicine, Universidad Complutense, 28040 Madrid, Spain
3. Ministerio de Agricultura, Pesca y Alimentación, 28010 Madrid, Spain
4. Biostatistics Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA