Moraxella bovoculi and Infectious Bovine Keratoconjunctivitis: Cause or Coincidence?

Moraxella bovoculi is a recently described gram-negative coccus that was isolated from eyes of calves with infectious bovine keratoconjunctivitis (IBK, or "pinkeye") in 2002. This organism probably has been associated with IBK for many years and, until it was shown to be distinct from M ovis, may have been incorrectly identified as M ovis, Branhamella ovis, M ovis-like, or B ovis-like by diagnostic laboratories. M bovoculi can be isolated from normal calves and cattle with IBK or conjunctivitis. An exact role for M bovoculi in the pathogenesis of IBK is uncertain; however, anecdotal evidence of autogenous M bovoculi bacterins successfully preventing IBK suggests that it may play a role in IBK pathogenesis. Developers of vaccines against IBK should consider including M bovoculi antigens in vaccines to prevent IBK.