Mastitis - Intro + immunity

Question 1

Name a major mastitis pathogen which is environmental in origin but can become cow adapted and become contagious?

Answer 1

Strep Uberis

Question 2

Which of these mastitis pathogens is Gram negative, environmental and is harboured inn poorly managed/damp sawdust?
1. E.coli
2. Staph aureus
3. Strep uberis
4. Klebisella

Answer 2

Klebsiella

Question 3

Which pathogen is Gram positive, always contagious, associated with chronically high cell counts and lives intracellularly?
1. Staph aureus
2. Strep uberis
3. Strep dysgalactiae
4. Strep agalactiae

Answer 3

Staph aureus

Question 4

What are consequences of mastitis infection?

Answer 4

• Chronic infection = spread of infection within herd
• Permanent damage = to udder - reduced milk yield
• Death = toxaemia

Question 5

What does the innate immune system consist of?

Answer 5

• Resident leucocytes - macrophages, neutrophils, T lymphocytes
• Lactopreoxidase
• Lysozyme
• Lactoferrin
• Complement

Question 6

What does the resident leucocytes do?

Answer 6

• Phagocytosis + killing of invading pathogens
• Trigger the acquired immune system by release of pro-inflammatory mediators + antigen presentation

Question 7

What does the rest of the innate immune response do?

Answer 7

• Lactoferrin = inhibits growth of bugs requiring iron (E.coli)
• Lactoperoxidase = bacteriostatic agent
• Lysozyme = bacteriocidal protein
• Free complement = opsonisation of bacteria, activated it attracts phagocytes

Question 8

What does the acquired immune system consist of?

Answer 8

• Invasion of circulating neutrophils + IgG2 antibodies
• B + T Lymphocytes
• Inflammatory cytokines

Question 9

What do the B lymphocytes do?

Answer 9

*Circulate through lymphatic system
*Exposed to antigens in tissue fluids
*Initial response produce IgM , IgG1
*Repeated exposure produce IgG2 antibodies (“vaccination”)
*IgG2 antibodies then circulate and enter inflamed udder aiding opsonisation of pathogens by neutrophils
*Present antigen to T lymphocytes

Question 10

What do the T lymphocytes do?

Answer 10

*T helper cells -production of cytokines following antigen recognition stimulates immune response
*T cytotoxic cells – eliminate host cells invaded by pathogens

Question 11

What do the different antibodies do?

Answer 11

*IgG2 most important antibody response
*IgM fixates complement for opsonisation of pathogens, agglutinates bacteria, neutralizes toxin
*IgA agglutination of bacteria and neutralize toxins
*IgG1 opsonisation of bacteria