Challenge Dose Titration in a Mycobacterium bovis Infection Model in Goats

Area of Science:

• Veterinary Medicine
• Infectious Diseases
• Immunology

Background:

• Goats are natural reservoirs for Mycobacterium bovis (M. bovis), causing economic losses.
• Goat models of M. bovis infection mimic human tuberculosis, offering research potential.

Purpose of the Study:

• To characterize Mycobacterium bovis challenge models in goats.
• To establish reproducible models for vaccine development.

Main Methods:

• Goats were endobronchially inoculated with varying doses of M. bovis.
• Clinical signs, pathogen shedding, and immune responses were monitored.
• Lesions were assessed via CT, histology, and bacteriology post-necropsy.

Main Results:

• Infected goats remained asymptomatic but showed positive immune responses (IGRA, antibodies, SICCT) and T-cell activation.
• M. bovis was cultured from feces, not nasal swabs.
• Paucibacillary granulomas formed in lungs and lymph nodes; high doses led to larger lesions and early generalization.

Conclusions:

• Reproducible M. bovis challenge models in goats were established.
• Dose-dependent lesion development was observed.
• These models are suitable for evaluating veterinary and human tuberculosis vaccines.