THE HISTOLOGICAL LESIONS OF EXPERIMENTAL GLANDERS

Area of Science:

• Veterinary Pathology
• Microbiology

Background:

• Glanders is a contagious disease caused by *Burkholderia mallei*.
• The bacillus of glanders can exhibit varying degrees of virulence.
• Histological manifestations of glanders lesions are not fully elucidated across different virulence levels.

Purpose of the Study:

• To investigate the histological features of glanders lesions experimentally induced by *Burkholderia mallei* of varying virulence.
• To correlate bacillary virulence and toxin concentration with specific cellular responses and lesion types.

Main Methods:

• Experimental inoculation of animals with *Burkholderia mallei* cultures of differing virulence.
• Histological examination of induced lesions.
• Analysis of cellular infiltration, necrosis, and proliferation patterns.

Main Results:

• Highly virulent cultures induced primary necrosis and polymorphonuclear leucocyte infiltration.
• Moderately virulent cultures resulted in acute inflammation without necrosis.
• Attenuated cultures led to primary tissue proliferation with epithelioid and giant cell formation.
• Lesion type (exudative vs. proliferative) correlated with bacillary toxin strength.
• Giant cells originated from endothelial cells via nuclear division, not cell fusion.
• Low virulence lesions were proliferative and histologically analogous to tuberculosis.

Conclusions:

• Bacillary virulence significantly dictates the histological presentation of glanders lesions.
• Glanders lesions are focal, with strong toxins causing necrosis and weak toxins promoting proliferation.
• The histological characteristics of glanders lesions provide insights into the pathogen-host interaction dynamics.