title: Respiratory disease caused by Mycoplasma bovis is enhanced by exposure to bovine herpes virus 1 (BHV-1) but not to bovine viral diarrhea virus (BVDV) type 2.
abstract: To determine if previous exposure to bovine viral diarrhea virus (BVDV) and bovine herpes virus 1 (BHV-1) type 2 affects the onset of disease caused by Mycoplasma bovis, 6- to 8-month-old beef calves were exposed to BVDV or BHV-1 4 d prior to challenge with a suspension of 3 clinical isolates of M. bovis. Animals were observed for clinical signs of disease and at necropsy, percent abnormal lung tissue and presence of M. bovis were determined. Most animals pre-exposed to BHV-1 type 2 but not BVDV developed M. bovis-related respiratory illness. In a second trial, we determined that a 100-fold reduction in the number of M. bovis bacteria administered to BHV-1 exposed animals reduced the percentage of abnormal lung tissue but not the severity of clinical signs. We conclude that previous exposure to BHV-1 but not BVDV type 2 was a necessary cause of M. bovis-related respiratory diseases in our disease model.
authors.affiliation: Vaccine and Infectious Disease Organization, Saskatoon, Saskatchewan, Canada.
authors.forename: Tracy
authors.initials: T
authors.lastname: Prysliak
authors.forename: Jacques
authors.initials: J
authors.lastname: van der Merwe
authors.forename: Zoe
authors.initials: Z
authors.lastname: Lawman
authors.forename: Donald
authors.initials: D
authors.lastname: Wilson
authors.forename: Hugh
authors.initials: H
authors.lastname: Townsend
authors.forename: Sylvia
authors.initials: S
authors.lastname: van Drunen Littel-van den Hurk
authors.forename: José
authors.initials: J
authors.lastname: Perez-Casal
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology* / Q000821:virology*; D060085:Coinfection / Q000382:microbiology / Q000662:veterinary* / Q000821:virology; D030242:Diarrhea Virus 2, Bovine Viral / Q000472:pathogenicity; D007242:Herpesvirus 1, Bovine / Q000472:pathogenicity*; D045682:Mycoplasma bovis / Q000472:pathogenicity*; D012141:Respiratory Tract Infections / Q000382:microbiology / Q000662:veterinary* / Q000821:virology