Test 2- Moraxella

Question 1

The genus Moraxella

Answer 1

Many Species

• Of importance
• M. bovis
• M. bovoculi
• M. ovis

Humans

• M. catarrhalis: pneumonia

Question 2

Moraxella bovis General

Answer 2

• Gram-negative pleomorphic rods
• Generally in pairs or short chains
• Non-motile
• Catalase & oxidase positive
• Obligate symbiotic
• Obligate pathogenic

• Quite resistant in the environment

Question 3

Answer 3

Moraxella bovis

Question 4

Moraxella bovis disease in bovines

Answer 4

• Infectious bovine keratoconjunctivitis or ‘Pink eye’

• Serous to purulent conjunctivitis and keratitis
• Highly infectious/contagious
• Mainly young animals

Question 5

Moraxella bovis Virulence

Answer 5

• Essential: fimbriae

———-Adhesion to host cell (eye): conjunctival and corneal epithelial cells

• Capsule
• LPS

• Exotoxins
——-Cytotoxin

——- Pore forming toxin

Question 6

Moraxella bovis Pathogenesis

Answer 6

1. Specific attachment of bacteria to conjunctival/corneal epithelia
2. Production of toxin

1 and 2 Destroy Tissue

3. Inflammation
4. further growth and production of toxins

3 and 4 Further damage

5. Increased susceptibility for other pathogens
6. Non infectious damage: dust,…

5 and 6 cause Irreversible eye damage

Question 7

Moraxella bovis Predisposing factors

Answer 7

• Young cattle
• Flies
• Eye irritation

—– Dust

—— Sun,…
• Bovine herpesvirus 1 infection (IBR)

• Mycoplasma bovoculi
• Listeria monocytogenes

Question 8

Moraxella bovis transmission

Answer 8

• Direct contact with infected animal

• Flies

Question 9

Moraxella bovis Diagnosis

Answer 9

• Immunofluorescence

• Culture
• Blood agar plates at 35°C
• Hemolytic colonies
• Oxidase +, non fermenting

• PCR

Question 10

Moraxella bovis

Prevention and treatment

Answer 10

• Prevention:

—– Flies

• —- Dust
• —- Elimination of other predisposing factors

—– No vaccine to date

• Treatment
• Antibiotics: local and eventually systemic

—– Tetracycline,florfenicol

• Corticosteroids

—– If inflammation is serious only because it can lower immunity
In separate stable (evt. dark) no flies/dust: transmission will decrease

Question 11

M. bovoculi

Answer 11

• Cocci
• Diplococci
• Associated with keratoconjunctivitis in bovines

—– much more rare

Question 12

M. ovis

Answer 12

• Cocci
• Associated with keratoconjunctivitis in bovines

• Associated with pneumonia in bovines

—– much more rare

Question 13

Question 14