[1] Minist Agr Forestry & Fisheries, Natl Inst Anim Hlth, Dept Exot Dis, Immunol Lab, Kodaira, Tokyo 1870022, Japan
[2] Minist Agr Forestry & Fisheries, Natl Vet Assay Lab, Assay Div 1, Kokubunji, Tokyo 1858511, Japan
[3] Nippon Vet & Anim Sci Univ, Dept Vet Pathol, Musashino, Tokyo 1808602, Japan
[4] Hokkaido Univ, Grad Sch Vet Med, Dept Dis Control, Sapporo, Hokkaido 0600818, Japan