부산대학교 도서관

Infectious bovine keratoconjunctivitis（IBK）, also known as pinkeye, is an infectious disease characterized by keratitis, which can progress into corneal ulceration in severe cases. IBK causes significant economic losses for farmers due to reduced weight gain and increased cost for antibiotic treatment. We examined the presence of Moraxella and Mycoplasma spp. in the conjunctiva of 36 Holstein heifers（12 heifers with corneal and conjunctival lesions, 12 heifers with conjunctival lesions, and 12 heifers with no ocular lesions）from a public farm where keratoconjunctivitis was prevalent. Moraxella bovoculi and Moraxella bovis were detected in 11 and 1 heifers with corneal and conjunctival lesions, in 4 and 5 heifers with conjunctival lesions（including one with mixed infection）,and in 1 and 4 heifers with no ocular lesions, respectively. Thus, Moraxella bovis, which is reported to be the main causative agent of IBK, was mainly detected in the heifers with no ocular lesions and those with conjunctival lesions. On the other hand, Moraxella bovoculi, which has an unclear role in the IBK pathogenicity, was mainly detected in cows with more severe keratoconjunctivitis with corneal and conjunctival lesions. Mycoplasma bovoculi was detected from 10 heifers with severe lesions, 10 heifers with mild lesions and 9 asymptomatic heifers, but no association was found between infection and severity of the eye lesions. In conclusion, understanding the role of Moraxella bovoculi infection is important in severe keratoconjunctivitis in cattle.