Bovine Infectious Bovine Keratoconjunctivitis – NAVLE Study Guide

Overview and Clinical Importance

Infectious bovine keratoconjunctivitis (IBK), commonly known as pinkeye or New Forest eye, is the most common ocular disease affecting cattle worldwide. It is a highly contagious bacterial infection primarily caused by Moraxella bovis, a Gram-negative, ?-hemolytic, aerobic, rod-shaped bacterium. IBK causes significant economic losses estimated at over $150 million annually in the United States due to decreased weight gain, reduced milk production, treatment costs, and decreased market value of affected animals.

The disease is characterized by inflammation of the cornea and conjunctiva, manifesting with blepharospasm, epiphora, photophobia, corneal edema, opacity, vascularization, and ulceration. Severe cases may progress to corneal perforation and permanent blindness. Young cattle, particularly calves, are most susceptible, with affected calves showing weaning weights approximately 8.9 kg (20 lbs) lower than healthy calves.

Etiology

Primary Causative Agent

Moraxella bovis is the primary etiologic agent of IBK. It is an obligate mucosal parasite found in the eyes and nasal cavities of infected cattle. Key characteristics include: