title: Virulence of two strains of mycobacterium bovis in cattle following aerosol infection.
abstract: Over the past two decades, highly virulent strains of Mycobacterium tuberculosis have emerged and spread rapidly in man, suggesting a selective advantage based on virulence. A similar scenario has not been described for Mycobacterium bovis infection in cattle (i.e. bovine tuberculosis). An epidemiological investigation of a recent outbreak of bovine tuberculosis in a USA dairy indicated that the causative strain of M. bovis (strain 10-7428) was particularly virulent, with rapid spread within the herd. In the present study, the virulence of this strain (10-7428) was directly compared in the target host with a well-characterized strain (95-1315) of relevance to the USA bovine tuberculosis eradication programme. Aerosol inoculation of 10(4) colony forming units of M. bovis 95-1315 (n = 8) or 10-7428 (n = 8) resulted in a similar distribution and severity of gross and microscopical lesions of tuberculosis as well as mycobacterial colonization, primarily affecting the lungs and lung-associated lymph nodes. Specific cell-mediated and antibody responses, including kinetics of the response, as well as antigen recognition profiles, were also comparable between the two treatment groups. Present findings demonstrate that M. bovis strains 95-1315 and 10-7428 have similar virulence when administered to cattle via aerosol inoculation. Other factors such as livestock management practices likely affected the severity of the outbreak in the dairy.
authors.affiliation: National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA. Electronic address: ray.waters@ars.usda.gov.
authors.forename: W R
authors.initials: WR
authors.lastname: Waters
authors.affiliation: National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Thacker
authors.affiliation: National Veterinary Services Laboratories, Veterinary Services, Animal and Plant Health Inspection Service, US Department of Agriculture, Ames, IA 50010, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Nelson
authors.affiliation: National Veterinary Services Laboratories, Veterinary Services, Animal and Plant Health Inspection Service, US Department of Agriculture, Ames, IA 50010, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: DiCarlo
authors.affiliation: National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA; Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Maggioli
authors.affiliation: Chembio Diagnostic Systems, Inc., Medford, NY 11763, USA.
authors.forename: R
authors.initials: R
authors.lastname: Greenwald
authors.affiliation: Chembio Diagnostic Systems, Inc., Medford, NY 11763, USA.
authors.forename: J
authors.initials: J
authors.lastname: Esfandiari
authors.affiliation: Chembio Diagnostic Systems, Inc., Medford, NY 11763, USA.
authors.forename: K P
authors.initials: KP
authors.lastname: Lyashchenko
authors.affiliation: National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA.
authors.forename: M V
authors.initials: MV
authors.lastname: Palmer
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D002417:Cattle; D008297:Male; D009163:Mycobacterium bovis / Q000472:pathogenicity*; D014380:Tuberculosis, Bovine / Q000276:immunology / Q000473:pathology*; D014774:Virulence
chemical_list: D000336:Aerosols
keywords: Mycobacterium bovis; bovine tuberculosis; immunity; virulence