1. School of Biological Sciences, University of Bristol; Tyndall Avenue Bristol BS8 1TQ UK
2. Cabot Institute, University of Bristol; Cantocks Close Bristol BS8 1TS UK
3. Department of Veterinary Medicine and Animal Productions; University of Naples Federico II; CREMOPAR; Regione Campania Naples Italy
4. Section of Veterinary Epidemiology; University of Zurich; Winterthurerstrasse 270 Zurich CH-8057 Switzerland
5. School of Veterinary Medicine, University College Dublin; Belfield Dublin Ireland
6. Moredun Research Institute; Pentlands Science Park Midlothian EH26 0PZ UK
7. Department of Virology; Parasitology and Immunology; Faculty of Veterinary Medicine; Ghent University; Salisburylaan 133 Merelbeke 9820 Belgium
8. Institute of Parasitology, University of Zurich; Winterthurerstrasse 266a Zurich CH-8057 Switzerland
9. Avia-GIS BVBA; Risschotlei 33 Zoersel 2980 Belgium
10. School of Veterinary Sciences, University of Bristol; Langford House Bristol BS40 5DU UK