Virulence of Two Strains of Mycobacterium bovis in Cattle Following Aerosol Infection

Effects of Serial Skin Testing with Purified Protein Derivative on the Level and Quality of Antibodies to Complex and Defined Antigens in Mycobacterium bovis-Infected Cattle

“…Upon necropsy (ϳ7 months after the challenge), each animal had tuberculous lesions primarily in the lungs and lung-associated (i.e., tracheobronchial and mediastinal) lymph nodes, typical of a low-dose aerosol M. bovis challenge (19,22). Infection was confirmed in each animal by isolation of M. bovis from the lesions.…”

“…For experimental infection, Holstein steers (n ϭ 8) received ϳ10 4 CFU of M. bovis strain 10-7428 by aerosol. Strain 10-7428 is a virulent (19) field isolate from a dairy cow in Colorado (20). In a separate study, treatment groups included noninfected Holstein steers (n ϭ 7), M. bovis strain 10-7428-infected (ϳ10 4 CFU by aerosol) Holstein steers (n ϭ 8), or M. bovis strain 95-1315-infected (ϳ10 4 CFU by aerosol) Holstein steers (n ϭ 8).…”

“…Enumeration of M. bovis challenge inocula, necropsy procedures (7 months after the experimental challenge), and gross and microscopic assessments of lesions were each performed as described previously (22). Qualitative assessment of mycobacterial colonization was performed using standard mycobacterial culture techniques (19)(20)(21)(22)(23), using Middlebrook 7H11 selective agar plates (Becton Dickinson) incubated for 8 weeks at 37°C, as well as IS6110 real-time PCR for confirmation of colonies, as described by Thacker et al (24). Strict biosafety protocols were followed throughout the study to protect personnel from exposure to M. bovis, including BSL-3 containment upon initiation of M. bovis challenges in animal rooms and standard BSL-3 laboratory practices for handling M. bovis cultures and samples from M. bovis-infected animals.…”

“…Chembio DPP technology was used to detect bovine IgG and IgM responses to the polyepitope fusion protein MPB83-MPB70 (14,19). As a detection system, goat anti-bovine IgG and anti-bovine IgM antibodies (Kirkegaard & Perry Laboratories) were conjugated to colloidal gold nanoparticles using Chembio standard procedures.…”

Interleukin-17A as a Biomarker for Bovine Tuberculosis

“…In the comparative virulence study, the levels of M. bovis colonization, distributions of lesions, and severity of gross and microscopic lesions were similar (P Ͼ 0.05) for the M. bovis strain 95-1315-and 10-7428-challenged groups (Table 1) (37). Tuberculous lesions were not detected and M. bovis was not isolated from any of the animals in the noninfected control group.…”