Pasteurellaceae isolated from bighorn sheep (Ovis canadensis) from Idaho, Oregon, and Wyoming.

Objective—To elucidate the species and biovariants of Pasteurellaceae isolated from clinically normal bighorn sheep (Ovis canadensis) or bighorn sheep with evidence of respiratory disease. Sample—675 Pasteurellaceae isolates from 290 free-ranging bighorn sheep in Idaho, Oregon and Wyoming. Procedures—Nasal and oropharyngeal swab specimens were inoculated onto selective and nonselective blood agar media. Representatives of each colony type were classified via a biovariant scheme. The association of respective β-hemolytic isolates with respiratory disease was evaluated via χ2 analyses. Results—Bacterial isolates belonged to 4 species: Histophilus somni, Mannheimia haemolytica, Pasteurella multocida, and Bibersteinia (Pasteurella) trehalosi. Within the latter 3 species, 112 subspecies, biotypes, and biovariants were identified. Bibersteinia trehalosi 2 and B trehalosi 2B constituted 345 of 675 (51%) isolates. Most (597/618 [97%]) isolates from adult sheep were from clinically normal animals, whereas most (47...