Revision of PGE

Question 1

Severity of PGE disease depends on which 3 factors?

Answer 1

• Concurrent infection
• Nutritional status of the sheep
• Development of the immune response

Question 2

What are the typical clinical signs of PGE?

Answer 2

• Profuse watery diarrhoea
• Weight loss
• Inappetence
• Dehydration
• Death

Question 3

Which animals are most affected by PGE?

Answer 3

First season grazing lambs

Question 4

Which worms cause PGE in the abomasum?

Answer 4

• Teladorsagia circumcincta
• Trichostrongylus axei
• Haemonchus contortus

Question 5

Which worms cause PGE in the small intestine?

Answer 5

• Nematodirus battus
• Cooperia spp
• Trichostrongylus spp

Question 6

Which worms cause PGE in the large intestine?

Answer 6

• Chabertia spp
• Oesophagostomum spp
• Trichuris spp

Question 7

When does PGE type 1 disease occur?

Answer 7

Mid-summer onwards

Question 8

What can be used to diagnose PGE?

Answer 8

Clinical signs

Faecal egg counts of 750epg

Question 9

What is the primary PGE causing species?

Answer 9

Teladorsagia circumcincta

Question 10

Describe the typical trichostrongyle life cycle

Answer 10

• Eggs passed in faeces
• Develop in the faecal pat
• L1 hatch and feed on the bacteria in the faecal pat, moult to L2 and L3 which is ensheathed
• Sheep eat L3 which are swallowed to the abomasum
• Burrows into gastric glands
• Develops to L4 and L5
• L5 (immature adults) emerge, into lumen of abomasum

Question 11

What is the PPP of trichostrongylus?

Answer 11

3 weeks

Question 12

What are the 3 sources of PGE infection?

Answer 12

• Peri-Parturient Rise (PPR) in ewes
• Hypobiosis of larvae
• Overwintered L3

Question 13

Overwintered L3 does out by…?

Answer 13

June

Question 14

The peak number of eggs on pasture occurs in ?

Answer 14

July/August

Question 15

The PPR occurs in?

Answer 15

April/May

Question 16

Name the Barbers pole worm

Answer 16

Haemonchus contortus

Question 17

Describe some features of Haemonchus contortus

Answer 17

• Spiral gut and ovaries in the female
• Cervical papillae
• Bursa
• Abomasum

Question 18

Describe the pathogenesis of infection with Haemonchus contortus

Answer 18

• Erosion of abomasal wall
• Severe haemorrhagic gastritis
• Severe anaemia
• Oedema
• Weight loss

Question 19

When does a Haemonchus disease outbreak occur, what is the main cause?

Answer 19

• Late summer
• Ewe is the main source of pasture contamination (PPR)
• L3 do not survive the winter

Question 20

What are the clinical signs of a Nematodirus battus infection?

Answer 20

Sudden (explosive) outbreaks of acute, watery diarrhoea

Inappetence, dehydration (thirsty!), abdominal pain, weight loss

Question 21

Which animals are affected by Nematodirus battus?

Answer 21

Lambs of 4-12 weeks old

Question 22

Describe the pathogenesis of Nematodirus battus

Answer 22

• Developing L5 destroy the mucosa
• Catarrhal enteritis
• Villous atrophy
• Fluid and nutrient absorption disrupted

Question 23

Describe the epidemiology/life cycle of Nematodirus battus

Answer 23

• L3 develops in the egg over the summer
• Overwinters as larvated egg
• Emergence of L3 en masse in the spring
• L3 on pasture are the infective stage

Question 24

What are the specific hatching requirements of an overwintered Nematodirus battus egg?

Answer 24

• Exposure to prolonged period of chill

- Exposure to mean day/night temperature of 10 degrees

Question 25

For disease to occur hatching must co-incide with?

Answer 25

• Presence of susceptible lambs

- Old enough to graze but before age immunity develops

Question 26

Describe the eggs of Nematodirus battus

Answer 26

150 microns in size, brownish coloured – these are shed onto pasture, which then overwinter