Veterinary microbiology
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Veterinary microbiology · Dec 2007
Randomized Controlled TrialPrevention of naturally occurring infectious bovine keratoconjunctivitis with a recombinant Moraxella bovis pilin-Moraxella bovis cytotoxin-ISCOM matrix adjuvanted vaccine.
To evaluate the efficacy of a recombinant Moraxella bovis pilin-M. bovis cytotoxin subunit vaccine to prevent naturally occurring infectious bovine keratoconjunctivitis (IBK; pinkeye), a randomized, blinded, controlled field trial was conducted during summer 2005 in a northern California herd of beef cattle. One hundred and one steers were vaccinated with ISCOM matrix (adjuvant control), recombinant M. bovis cytotoxin carboxy terminus+ISCOM matrix (MbxA), or recombinant M. bovis pilin-cytotoxin carboxy terminus+ISCOM matrix (pilin-MbxA); calves received secondary vaccinations 21 days later. Calves were examined once weekly for 18 weeks for the development of corneal ulcers associated with IBK. ⋯ In addition, vaccination of calves with MbxA and pilin-MbxA resulted in a higher prevalence of Moraxella bovoculi sp. nov. in ocular cultures. While no significant difference was observed between a cytotoxin versus pilin+cytotoxin vaccine against IBK, the reduced cumulative proportion of IBK in the pilin-cytotoxin vaccinated calves suggests it may provide an advantage over a cytotoxin vaccine alone. Efficacy of an M. bovis vaccine may be reduced in herds where IBK is associated with M. bovoculi sp. nov.