[1] Univ Saskatchewan, Western Coll Vet Med, Large Anim Clin Sci, Saskatoon, SK S7N 5E2, Canada
[2] Univ Montreal, Fac Vet Med, Swine & Poultry Infect Dis Res Ctr, St Hyacinthe, PQ J2S 2M2, Canada
[3] Univ Saskatchewan, Western Coll Vet Med, Dept Vet Microbiol & Immunol, Saskatoon, SK S7N 5E2, Canada
[4] Univ Utrecht, Fac Vet Med, Dept Populat Hlth, Utrecht, Netherlands