[1] Danish Vet Inst, DK-4771 Lindholm, Kalvehave, Denmark
[2] Danish Vet Inst, DK-4771 Kalvehave, Denmark
[3] Royal Vet & Agr Univ, Dept Pharmacol & Pathobiol, Lab Vet Pathol, DK-1870 Frederiksberg C, Denmark
[4] Royal Vet & Agr Univ, Dept Pharmacol & Pathobiol, Lab Vet Pathol, DK-1870 Frederiksberg C, Denmark