A Study on Mycoplasmal and Viral Infections in Bovine Keratoconjunctivitis

Background: Infectious bovine keratoconjunctivitis (IBK or “pink eye”) is the most common infectious ocular disease in cattle worldwide. In addition to Moraxella bovis as the principal causative agent, infectious bovine rhinotracheitis virus (BHV-1) and Mycoplasma species probably act as risk factors for IBK. Objectives: This study aimed to evaluate the association between the detection of Mycoplasma sp., bovine herpesvirus 1 (BHV-1), and bovine viral diarrhea virus (BVDV) in the conjunctival sac of the eye and IBK. Methods: Polymerase chain reaction (PCR) was employed to detect Mycoplasma sp., BHV-1, and BVDV in samples collected from IBK-affected and healthy eyes. Results: Based on the PCR results, Mycoplasma sp. was detected in 63.6% and 47.2% of IBK-affected and healthy eyes, respectively. BHV-1 was detected in 59.1% and 36.1% of affected and healthy eyes, respectively. BVDV was detected in 65.9% and 58.3% of affected and healthy eyes, respectively. BHV-1 was the only agent significantly (P<0.05) associated with IBK lesions (isolated from 59.1% of affected vs 36.1% of healthy eyes). Conclusion: Based on the study results, BHV-1 may be a risk factor in the pathogenesis of infectious bovine keratoconjunctivitis, and mechanisms other than immune depression might be involved in its pathogenicity.