1. Animal Health and Veterinary Laboratories Agency, Addlestone, Surrey, UK.
2. Virologie Immunologie Moléculaires, U892, Institut National de la Recherche Agronomique, Jouy‐en‐Josas, France.
3. Friedrich‐Loeffler‐Institut, Federal Research Institute for Animal Health, Greifswald‐Insel Riems, Germany.