M5 Pathology

Question 1

5 Signs of systemic involvement

Answer 1

1. Fevered carcass
2. Petechial haemorrhages
3. Acute or active abscesses
4. Other acute/active lesions
5. Enlarged spleen

Question 2

How disease gets into an animal

Answer 2

1. Inhalation
2. Ingestion
3. Trauma
4. Congenital
5. Copulation

Question 3

Causes of disease (4)

Answer 3

1. Physical - migrating parasites
2. Physiological - emaciation
3. Chemical - ISL, adenocarcinoma
4. Infectious - bacteria, virus, parasites

Question 4

How does disease spread

Answer 4

Tissue to tissue
Tissue spaces
Blood
Lymph

Question 5

What do Parasites do?

Answer 5

1. Cause extensive tissue damage
2. Rob the host of food
3. Mechanical obstruction of passages by compression of organs
4. Cause traumatic damage
5. Cause secondary infections by bacteria

Question 6

6 Bacteria examples

Answer 6

1. Tetanus
2. TB
3. Lepto
4. Listeria
5. CLA
6. Gangrene

Question 7

6 Viral examples

Answer 7

1. Foot and mouth
2. Influenza
3. Scrapie
4. Hepatitis
5. ORF
6. AIDS

Question 8

6 Parasite examples

Answer 8

1. Lice
2. Ticks
3. Fleas
4. Worms
5. Hydatids
6. Liver fluke
7. Trichinosis

Question 9

How does bacteria cause disease?

Answer 9

They produce and secrete toxins and destroy tissues

• evade WBC
• turn off (trick)
• interfere with temperature
• attack healthy cells

Question 10

Disease process (9)

Answer 10

1. Cell damage
2. Chemotaxis
3. Hyperaemia
4. Inflammatory exudate (forms fibrin)
5. Fibrin forms around infection
6. Abscess
7. Fibrin forms over the infection
8. Repair
9. Resolved

Question 11

Describe how pathogens invade the body via inhalation

Answer 11

A pathogen can be breathed in, in the form of dust or fumes or carried in with oxygen. They attach to the mucus of the mouth and carried to the pluck (or GIT)

Question 12

Describe how pathogens invade the body via Ingestion

Answer 12

A pathogen can be taken to the GIT through the fodder

Question 13

Describe how pathogens invade the body via Trauma

Answer 13

Any physical injury or wound (tripping/shearing/docking, arthritis) may cause formation of an abscess as the result of infection, migrating parasites

Question 14

Describe how pathogens invade the body via parasites

Answer 14

Destroy tissues and organs, rob the host of food, and can cause secondary infection by bacteria and transmitting other diseases

Question 15

Describe how bacteria in a liver abscess can spread to the spleen

Answer 15

Contiguous spread from tissue to tissue (close proximity)

Question 16

Describe how bacteria in a liver abscess can spread to the kidneys

Answer 16

Through arterial circulation (blood)

Question 17

Explain how cells from a cancer in the mesentery can spread to the liver

Answer 17

Tissue to tissue, or via the mesenteric vein to the liver (portal circulation)

Question 18

What is the red ring of tissue that forms around an infection site?

Answer 18

Dilated blood vessels increasing blood supply at the site of infection (still resolving) - hyperaemia

Question 19

How would you describe an acute disease

Answer 19

Redness, swelling, LN involvement, short duration

Question 20

What are the signs of chronic disease

Answer 20

Presence of white fibrous tissue (enlargement), long duration, probably no LN involvement

Question 21

Signs of an active lesion

Answer 21

Could have fibrin, swollen, may have LN involvement

Question 22

Describe how a capsule forms around an infection site

Answer 22

Inflammatory exudate, fibrin, white fibrous tissue forms around the infection, forms a capsule. Pus develops within the capsul. Pus consists of: bacteria, WBC, dead cells and exudate

Question 23

How would you describe an abscess in a parotid LN, a smaller but similar abscess int the atlantal LN

Answer 23

Acute and actively progressive

Question 24

How would you describe a large chronic abscess in the submaxillary LN, smaller but similar abscesses in the lung tissue, mesenteric LN’s and liver

Answer 24

Generalised because it has spread to different regions of the body (only portal system)

Question 25

What is the term Generalised

Answer 25

Wide spread through the body, doesn’t always have to involve the blood, may not always be a food safety issue

Question 26

What is the term Systemic

Answer 26

Involves the aorta (cause is in the blood), always active or acute, always food safety issue

Question 27

How would you describe a small acute abscess in the submaxillary LN, similar abcesses in the lung tissue, spleen and kidney

Answer 27

Systemic because it is acute and involves the aorta

Question 28

Significance of petechial hemorrhages

Answer 28

With PH - it is a classic or common sign of systemic involvement

Question 29

Why are generalised conditions not usually kept

Answer 29

1. Yuck factor 2. Possibility with some conditions for it to be food safety issue (Icterus, Uremia) 3. Not practical to trim (eg. with ovis)

Question 30

Why would blood for edible purposes be unsuitable if it was saved from an animal that was condemned for multiple abscesses

Answer 30

The blood may be contaminated with bacteria and therefore a food safety issue

Question 31

Why would a liver with a small abscess not be suitable for petfood

Answer 31

Bacteria can contaminate other food product, surfaces and personnel. It may still not be destroyed

Question 32

Signs of benign disease (6)

Answer 32

1. Slow growing 2. Encapsulated 3. Well defined borders 4. Won't spread 5. Grows on and out of tissues 6. Pink centre

Question 33

Signs of malignant disease (6)

Answer 33

1. Rapid growing 2. No capsule 3. No defined border 4. Spreads and invasive 5. Grows in and through tissues 6. Necrotic centre

Question 34

Two keywords for repair process

Answer 34

1. Shrink | 2. Bind

Question 35

The effects of cancer on the body

Answer 35

1. Rob of nutrients (intestines)/vitality (metabolism) (Loss of weight) 2. Destroys healthy tissues 3. Pressure from getting bigger and bigger - interupt lymph drainage 4. Secondary infections