Infectious Bovine Keratoconjunctivitis: A Bacterial Infection that Causes Pain in the Eye

Infectious bovine keratoconjunctivitis, commonly known as pinkeye in cattle, is a highly contagious bacterial infection of the eye. This infection is not fatal but has a tremendous economic impact on the cattle industry. Pinkeye is the result of infection of the surface of the eye by the bacterial organism Moraxella Bovis, and several other viruses and bacteria. This infection tends to be acute and spread very quickly. It can affect one or both of the eyes at the same time.

Causes, Spreading, and Risk Factors of Infectious Bovine Keratoconjunctivitis

Infectious keratoconjunctivitis is a common ocular condition of cattle, sheep, and goats that is characterized by issues such as ulceration, lacrimation, conjunctivitis, blepharospasm, and varying degrees of corneal opacity. In severe cases, this infection can even lead to blindness. While cattle of all ages can develop this disease, however, young stock is more commonly affected. Outbreaks of this infection are also more common during warmer months of the year.

Infectious bovine keratoconjunctivitis is the result of the infection of the surface of the eye by the bacterial organism Moraxella bovis. However, several other viruses and bacteria, such as Mycoplasma bovis and Moraxella bovoculi, may also increase the chances of infection. Once the cattle are exposed to Moraxella bovis, the organism continues to reside on the eyes and in the nasal cavities of the infected cattle.

Some carriers of the disease may be asymptomatic and carry the bacterial organism for at least a year. On the other hand, the transmission of the disease occurs through contact with secretions infected with Moraxella bovis. This disease can also be transmitted through direct contact or through contact with inanimate objects. Face flies are a common spreader of this disease as they travel from animal to animal.

The cattle are at a higher risk of catching IBK when they are-

• Dust

• Flies

• Ultraviolet solar radiation

• Mechanical irritation

• Infectious agents, such as Thelazia spp, Acholeplasma oculi, listeria monocytogenes, and Moraxella ovis.

• Recent commingling

• Attendance at shows and auctions

Clinical Signs of Infectious Bovine Keratoconjunctivitis

There are several signs and symptoms of infectious bovine keratoconjunctivitis-

• Excessive tearing

• Photosensitivity

• Ocular pain

• Corneal ulceration to rupture

• Depression of appetite due to inability to locate food.

There are four stages of infectious keratoconjunctivitis

• Stage 1- In the first stage of keratoconjunctivitis, the affected eyes have excessive tearing and increased sensitivity to light. Cows tend to blink frequently and the white portion of the eye will turn red to inflammation.

• Stage 2- In the second stage of keratoconjunctivitis, the clinical signs progress and the ulcer spreads across the cornea. The cornea becomes increasingly cloudy as additional inflammation occurs.

• Stage 3- The ulcer continues to spread and progress. The inflammation continues to spread into the inner parts of the eyes. The eyes will have a yellow appearance versus the typical brown colour.

• Stage 4- The ulcer extends completely through the cornea and the iris starts protruding through the ulcer.

Prevention of Infectious Bovine Keratoconjunctivitis

• It is imperative to control the face fly population because they are responsible for transmission.

• An appropriate vaccination program that includes infectious bovine rhinotracheitis and bovine viral diarrhoea virus along with a good nutrition and mineral program to decrease the incidence of pinkeye.

• Clipping pastures will prevent seed-head development as it will reduce irritation to the eyes of cattle.

• Check mineral feeders and other areas for frayed or sharp edges that can easily damage the cornea and potentiate disease.

Treatment for infectious bovine keratoconjunctivitis

Treatment includes antibiotics based on the susceptibility of specific pathogens and supportive care. Another common treatment for IBK is bulbar conjunctival injection with penicillin. Sprays and topical ointments are only effective if used multiple times daily.