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*Decreased weight gain in beef cattle, decreased milk production in dairy herds
*Decreased weight gain in beef cattle, decreased milk production in dairy herds
*Age-related immunity due to previous exposure
*Age-related immunity due to previous exposure
*Antibodies against haemolysin neutralise different strains, whereas antibodies to fimbriae are strain-specific
*Asymptomatic carrier animals harbour the bacteria in the nasolacrimal ducts, nasopharynx and vagina
*Asymptomatic carrier animals harbour the bacteria in the nasolacrimal ducts, nasopharynx and vagina
*Transmission by direct contact, aerosol and via flies
*Transmission by direct contact, aerosol and via flies
*Clinical signs: blepharospasm, conjunctivitis, lacrimation
*Clinical signs: blepharospasm, conjunctivitis, lacrimation
*Keratitis and corneal ulceration, opacity and abscessation may lead to panophthalmitis and permanent blindness
*Keratitis and corneal ulceration, opacity and abscessation may lead to panophthalmitis and permanent blindness
*Stromal oedema; coning of cornea
*Cornea may heal or undergo permanent scarring
===Diagnosis===
*Swabs of lacrimal secretions
*Fluorescent antibody test demonstrate presence of ''M. bovis''
*Culture on blood agar; colonies are round, small, shiny and friable
*Virulent strains surrounded by complete haemolysis and are embedded in the agar
*No growth on MacConkey
*Autoagglutination in saline
*Short Gram negative rods on smears
*7 serotypes based on fimbriae
===Treatment and control===
===Treatment and control===
*Subconjunctival or topical antimicrobials
*Isolate animals
*Reduce mechanical irritation
*Insect control
*Prophylactic oxytetracycline for animals at risk
*Vitamin A supplementation