Nemotodes

Question 1

Name the 5 main nematodes that we need to learn + name there host/ site

Answer 1

1. Telodorsagia Circumcincta = Abomassum of ruminants
2. Trichostrongylus spp. = Small Intestine + Abomassum of ruminants, Stomach of horses
3. Cooperia spp. = Small Intestine of ruminants
4. Haemonchus Contortus = Abomassum of sheep
5. Nematodirus battus = Small Intestine

Question 2

Define ‘Pre-Patent Period’

Answer 2

time taken from time of infection to detection of eggs in faeces

Question 3

What is the meaning of ‘hypobiosis’?

Answer 3

arrested development of larvae within host in response to trigger received by free living L3 (< temp)

Question 4

Describe the identification features of telodorsagia circumcinta + how to distinguish b/w male/ female

Answer 4

• cervical papillae (male + female)
• males have bursa + spicules
• females are larger + have pointed tail end- may be able to see eggs in uterus

Question 5

Describe a typical Trichostrongyle lifecycle

Answer 5

• direct (no intermediate host)
• worms in abomassum > mate > females produce eggs > eggs develop in faecal pat > L1 hatches > feeds + moults to L2 > L2 moults to L3 > L3 (ensheathed) released from faeces by rain > L3 ingested > develops to L4 + L5 > L5 emerges + matures to adult

Question 6

Name to nematodes that follow a typical Trichostrongyle lifecycle

Answer 6

Telodorsagia Circumcinta, Trichostrongylus spp., Cooperia spp., Haemonchus Contortus

Question 7

What are the clinical signs of Telodorsagia Circumcincta infection?

Answer 7

weight loss/ poor weight gain, diarrhoea, dehydration, death

Question 8

What disease is cause by large numbers of Telodorsagia Circumcincta?

Answer 8

PGE (Parasitic Gastro- Enteritis)

Question 9

What is a parasite?

Answer 9

An organism that is dependent metabolically on another where the organism benefits at the expense of the other

Question 10

Describe the anatomy of the digestive system of a nematode

Answer 10

Mouth > Buccal cavity > Oesophagus > Intestine > Anus

Question 11

How do large numbers of Telodorsagia Circumcinta cause disease in ruminants?

Answer 11

>pH in abomassum which causes loss of bacteriostasis = ‘leaky’ abomasal mucosa

Question 12

Describe the typical hosts for infection by Telodorsagia Circumcincta

Answer 12

1st season lambs

Question 13

Describe the identification features of Trichostrongylus spp.

Answer 13

• well developed excretory notch
• males have a bursa + short spicules

Question 14

What disease does large numbers of Trichostrongylus cause?

Answer 14

PGE (Parasitic Gastro-Enteritis)

Question 15

What are the clinical signs of Trichostrongylus infection?

Answer 15

black scour, weight loss/ poor weight gain, poor skeletal growth

Question 16

What does Trichostrongylus cause leading to the clinical signs?

Answer 16

vilous atrophy, haemorrhage

Question 17

What season does Trichostrongylus spp. typically cause infection + what is their typical host?

Answer 17

Autumn disease of store lambs

Question 18

Describe the identification features of Cooperia spp.?

Answer 18

• Coiled appearance
• Small cephalic vesicle around head
• Males have short stumpy spicules

Question 19

What does heavy infections of Cooperia cause?

Answer 19

catarrhal enteritis, vilous atrophy, oedema of intestinal mucosa

Question 20

Describe the lifecycle of Nematodirus battus

Answer 20

Unembryonated eggs shed in faeces onto pasture > L1 > L3 develops in egg > L3 hatches > L3 ingested > L3- L4 reaches lumen of SI > L4 burrows into mucosa of SI > L5 emerges + adults mature in SI

Question 21

Describe the typical identification features of Nematodirus battus

Answer 21

• ‘tangled cotton wool’
• bubble-like cephalic vesicle
• males have long thin spicules
• females have large eggs within uterus
• thin + coiled w/ distinct buccal capsule

Question 22

What does infections of large numbers of Nematodirus battus cause and why?

Answer 22

Developing L5 destroy mucosa = catarrhal enteritis, vilous atrophy, fluid + nutrient absorption disrupted

Question 23

What are the clinical signs of Nematodirus battus infection?

Answer 23

sudden outbreaks of acute watery diarrhoea, inappetence, dehydration, abdominal pain/ weight loss

Question 24

Describe the typical host of Nematodirus battus

Answer 24

lambs 4-12 wks old

Question 25

Describe the identification features of Haemonchus contortus

Answer 25

• Large
• Cervical papillae
• Females have white ovaries wrapped around gut
• Males have asymmetrical dorsal lobe

Question 26

What does infection of Haemonchus Contortus cause and why?

Answer 26

Adults feed on blood = erosion of abomasal wall, severe haemorrhagic gastritis

Question 27

What are the clinical signs of Haemonchus Contortus infection?

Answer 27

anaemia, pale mucous membranes, ‘bottle jaw’ appearance

Question 28

Describe the typical host of Haemonchus contortus + time of year of infection

Answer 28

1st season grazing lambs, August/ September

Question 29

Identify this worm…

Answer 29

Telodorsagia circumcinta

• male = smaller than female

Question 30

Identify this worm egg and describe what features enable this identification…

Answer 30

Telodorsagia circumcincta

• barrel-shaped
• undifferentiated -> contain undeveloped morula
• undistinguishable from other trichostrongyle eggs