Pinkeye (contagious conjunctivitis) in cattle is most commonly caused by which organism?

Pinkeye (contagious conjunctivitis) in cattle is most commonly caused by which organism?

• A. Haemophilus aegypti
• B. Moraxella bovis
• C. Streptococcus pyogenes
• D. Staphylococcus aureus

Answer: (B)

Pinkeye in cattle is a contagious conjunctivitis most classically caused by Moraxella bovis. This organism adheres to the ocular surface and produces toxins that damage the corneal epithelium, leading to conjunctivitis and often keratitis or corneal ulcers. It spreads readily among cattle, especially in warm, dusty conditions, with face flies playing a major role in transmission. Among the options, Moraxella bovis is the one most consistently linked to this disease in cattle. The other organisms listed are not typical primary agents of contagious bovine conjunctivitis: Haemophilus aegyptius is a human conjunctivitis pathogen, while Streptococcus pyogenes and Staphylococcus aureus are more commonly associated with other infections in different species or contexts.

Pinkeye in cattle is a contagious conjunctivitis most classically caused by Moraxella bovis. This organism adheres to the ocular surface and produces toxins that damage the corneal epithelium, leading to conjunctivitis and often keratitis or corneal ulcers. It spreads readily among cattle, especially in warm, dusty conditions, with face flies playing a major role in transmission. Among the options, Moraxella bovis is the one most consistently linked to this disease in cattle. The other organisms listed are not typical primary agents of contagious bovine conjunctivitis: Haemophilus aegyptius is a human conjunctivitis pathogen, while Streptococcus pyogenes and Staphylococcus aureus are more commonly associated with other infections in different species or contexts.