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.


METHODS
675 Pasteurellaceae isolates from 290 free-ranging bighorn sheep in Idaho, Oregon and Wyoming.


METHODS
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 χ(2) 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 (47/57 [82%]) isolates from lambs were from animals with evidence of respiratory disease. Twenty-two Pasteurellaceae biovariants were isolated from sheep with respiratory disease; 17 of these biovariants were also isolated from clinically normal sheep. The ability of isolates to cause β-hemolysis on blood agar was associated with respiratory disease in adult bighorn sheep (OR, 2.59; 95% confidence interval, 1.10 to 6.07).


CONCLUSIONS
Bighorn lambs appeared more susceptible to respiratory disease caused by Pasteurellaceae than did adult sheep. β-Hemolytic Pasteurellaceae isolates were more likely to be associated with respiratory disease than were non-β-hemolytic isolates in adult sheep. Identification of Pasteurellaceae with the greatest pathogenic potential will require studies to estimate the risk of disease from specific biovariants.
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
David S
DS
Miller
Glen C
GC
Weiser
Alton C S
AC
Ward
Mark L
ML
Drew
Phillip L
PL
Chapman
D000818:Animals; D016009:Chi-Square Distribution; D005260:Female; D007061:Idaho / Q000453:epidemiology; D008297:Male; D009922:Oregon / Q000453:epidemiology; D015661:Pasteurellaceae / Q000145:classification / Q000302:isolation & purification*; D016871:Pasteurellaceae Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D012140:Respiratory Tract Diseases / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000382:microbiology*; D034581:Sheep, Bighorn; D014959:Wyoming / Q000453:epidemiology