Infectious bovine keratoconjunctivitis: evidence for general immunity

Area of Science:

• Veterinary Immunology
• Ophthalmology
• Bacterial Infections

Background:

• Infectious bovine keratoconjunctivitis (IBK) is a common eye disease in cattle.
• The immune response to Moraxella bovis, the causative agent of IBK, is not fully understood.
• Determining the nature of acquired immunity is crucial for understanding disease resistance.

Purpose of the Study:

• To investigate whether immunity acquired after an initial Moraxella bovis infection is localized to the affected eye or represents a generalized systemic response.
• To differentiate between local and systemic immune mechanisms in the context of IBK.

Main Methods:

• Experimental infection of calves with Moraxella bovis.
• Principals: exposed to M. bovis in one eye then both eyes.
• Controls: exposed to M. bovis in both eyes at different time points.

Main Results:

• Principal calves showed significantly shorter infection duration in the unexposed right eye compared to the initially infected left eye and control eyes (P < 0.001).
• Fewer principal calves developed IBK in the right eye upon secondary exposure (day 21) compared to control groups.
• No significant difference in infection duration was observed between control groups or in the left eyes of principal calves.

Conclusions:

• Acquired resistance to Moraxella bovis infection following initial exposure is likely mediated by a generalized immune response.
• The findings suggest systemic immunity plays a significant role in protecting cattle against subsequent IBK episodes.