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Flashcards in FA Trichostrongylidae Deck (66):
1

Brown stomach worm is also known as...

Ostertagia ostertagi

2

In which area of the rumen would adult ostertargia be found?

Abomasum

3

Outline the morphological features of the adult Ostertagia.

1cm in length

Slender

Pink-brown

Fine cervical papillae - finger-like projections

Bursal spicules - male

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4

Where in the abomasum would Ostertagia be found?

The gastric glands

5

Describe the pathologenic features of Ostertagia infection.

  1. Damages parietal cells
    1. Increase in pH to pH7
    2. Build up of pepsinogen
    3. No bacteriostatic effects of HCl
    4. Loss of cell-to-cell adhesion = plasma protein leakage (albumen)
    5. Pepsinogen transferred to plasma
  2. Replacement of parietal cells with undifferentiated epithelial cells - loss of abomasal function

 

6

What is the gross appearance of an ruminant abomasum affected by ostertagia?

Nodular hyperplasia of gastric glands

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7

Describe the morphology of Ostertagia eggs.

  • 90x45um
  • barrel shaped
  • undifferentiated morula

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8

Outline the lifecycle of Ostertagia

Cattle eats L3

L3 reaches abomasum and burrows into gastric glands

Develops to L4/5

L5 emerges and develops to adults

Adult lays eggs which are passed in faeces

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9

What is shown in this histo slide?

What are the consequences of this stage of OO lifecycle?

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A larval OO within the gastric gland of the abomasum

Consequences:

  • Damages parietal - decreased HCl secretion - loss of bacteriostatic effect
  • Loss of cell-to-cell adhesion - protein losing enteropathy
  • Replaced by undifferentiated epithelium - loss of abomasal function
  • Reduced pepsin production - build up of pepsinogen

10

Describe Type 1 ostertagiosis.

July - September (August)

Large numbers of L3 ingested in July 

Green watery diarrhoea

Usually dairy replacement heifers

11

Describe Type 2 ostertagiosis

Occurs due to simultaneous emergence of hypobiosed larvae from gastric glands after winter

  • Acute 
  • Intermittent diarrhoea
  • Anaemia
  • Thirst
  • High mortality

12

Name the worms found in the abomasum of sheep and cattle

  • Haemonchus contortus (3cm)
  • Ostertagia ostertagi (1cm)
  • Trichostrongylus axei (0.5cm)

HOT in order of size

13

Name the worms found in the small intestine of sheep and cattle.

  • Nematodirus spp (cephalic vesicle, ‘cotton wool’ large eggs)
  • Trichostrongylus spp
  • Cooperia spp (‘watch spring’; cephalic vesicle, typical trichostrongyle eggs)

14

Name the worms found in the large intestine of cattle and sheep.

  • Chabertia spp
  • Oesophagostomum spp
  • Trichuris spp

COT

15

What factors are necessary for development of pre-parasitic stages of OO?

  • Temperature > 10o
  • Humidity/ rainfall - dispersal of faecal pat

16

Describe Hypobiosis

Parasite triggered arrest in development WITHIN the host. L3 on pasture detect drop in temperature which triggers L4 to hypobiose once in host.

17

What factors affect parasitic development on pasture?

  • Ensheathed - cuticle of L2
  • Temperature - tolerates cold up to a point 
  • Moisture - dessication is lethal
  • Limited food reserves and therefore lifespan (>/< PPP)

18

What host factors affect OO development?

  • Age - younger tend to be more susceptible
  • Immune status - need repeat infection to develop immunity
  • Over-dispersion - 80:20

19

What time of year would t1 ostertagiosis be expected? Why?

August to September

Three weeks after ingestion of large numbers of L3 (PPP). Peak L3 are seen on pasture in July, best conditions for development.

20

When is T2 ostertagiosis most likely to develop? Why?

Late winter- early spring.

When L5 simutaneously emerge from the gastric glands

21

What diagnostics are used to dx. OO?

Plasma pepsinogen levels are raised

Clinical signs

Grazing history

22

Dictyocaulus spp. are what type of worm?

Trichostrongyle

23

Name a species of Dictycaulus which occurs in sheep and goats in the tropic and sub-tropics.

Dictyocaulus filaria

24

Which species of Dictyocaulus causes respiratory disease in horses and patent infection in donkeys?

Dictyocaulus arnfieldi

25

Husk aka

Parasitic bronchitis

26

Describe the morphology of adult Dictyocaulus viviparus.

Where in the sheep are they found?

4-8 cm long

Slender, white

Male has reduced bursa, food granules within worm, cuticular knob at anterior end

Found in trachea and bronchi

27

Outline the lifecycle of D. viviparus

Penetration - d0-7 - Lympho-tracheal migration of L3, moult to L4 in LN and reaches lungs

Pre-patent - d8-25 - L4-5 in the lungs, migrates up brochial tree, adults in bronchi and trachea

Patent - d26-55 - Adult worms in URT, lays eggs-L1

Post-patent - d55+ - Immune expulsion of adults, protective immunity develops

28

Describe the morphology of iL3 D. vivaparus.

Double sheathed - L1/2

Short/ stumpy

Contain food granules

29

What clinical signs are associated with the pre-patent phase?

Intense inflammatory response

  • alveolitis, bronchiolitis, brochitis
  • Interstitial emphysema
  • Pulmonary oedema
  • Coughing
  • Respiratory distress
  • Tachypnoea
  • Wt loss

30

What clinical signs are associated with the patent phase of D. vivparus?

  • Mature adults in Bronchi/trachea
  • Eggs/larvae swept into alveoli
  • Intense inflammatory response
  • Frothy, white mucus
  • Emphysema
  • Hypoxia
  • Respiratory distress and death

31

What clinical signs are associated with the post-patent phase of Dictyocaulus vivparus?

Resolved clinical signs

If epithelialisation of lung tissue occurs it may never fully recover - poor doers

32

Which fungal species can be responsible for wide dispersion of D. viviparus?

Pilobolus fungi

  • Grows on the surface of the faecal pat
  • L3 migrate up the fungal body
  • When the fungal fruiting bodies explode L3 are dispersed across pasture

 

33

Outline the diagnosis and treatment of DV.

Dx.

  • Clinical signs
  • Baerman - L1 in faeces
  • Ab ELISA - for monitoring rather than dx.

Tx

  • Rapid anthelmintics
  • NSAIDS
  • Abs
  • Supportive care

34

Describe the vaccination used against DV.

Live attenuated - 1000 irradiated L3

Oral

2 x doses before turnout

35

Name a trichostrongyloid which affects lamb and is found in the small intestine.

Nematodirus battus

36

Describe the morphology of Nematodirus battus.

"Thread worm" can be found in large spaghetti like groups

Have a bubble-like cephalic vesicle

Males have long, thin spicules

Females have large eggs within the uterus

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37

Describe the differences between different species of Nematodirus.

Battus - eggs have parallel sides and a brown shell

Filicollis - eggs have rounded sides and clear shell

38

What is the pre-patent period of Nematodirus battus?

15 days

39

What is the infective stage of the lifecycle of Nematodirus battus?

L3 which has hatched from the egg

40

Which lifecycle stages are found within the egg of Nematodirus battus?

L1 - L3 (l3 hatches)

41

Describe the pathology of Nematodirus battus? 

Developing l5 destroy mucosa

Effects: catarrhal enteritis, villous atrophy, disruption of fluid and nutrient absorption

42

What clinical signs are associated with outbreaks of Nematodirus battus?

What age of lamb is it often associated with?

Sudden explosive outbreaks of diarrhoea (watery)

Inappetence

Dehydration

Abdominal pain

Weight loss

4-12 weeks 

43

What climatic conditions are required for development of Nematodirus battus larvae on pasture?

When is emergence of larvae often observed?

1. Exposure to prolonged period of chill

2. Exposure to mean day/ night temperature of 10oC

3. Emergence around Spring 

44

Which anthelmintic is N. battus NOT susceptible to? 

Inj Macrocyclic lactones (moxidectin)

Instead use BZ or Imidaclopride

45

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Lancet tooth of Haemonchus contortus

46

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Large bursal cavity of Haemonchus contortus - large lateral lobes with Y dorsal lobes and rays

47

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Intertwining gut and uterus of Haemonchus contortus

48

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Cervical papillae of Haemonchus contortus

49

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Short, unequal spicules of Trichostrongylus axei

50

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Excretory notch of Trichostrongylus axei

51

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Ovijector of Trichostrongylus axei - Holds and expels eggs from parasite

52

True or false

Ostertagia/ telodorsagia have cervical papillae?

TRUE

53

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Long, thin spicules of Nematodirus battus

Fused at the tip!

54

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Cephalic (bubble-like) vesicle (more prominent than cooperia)

55

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Large eggs seen in the uterus of Nematodirus battus

56

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Watch-spring appearance of cooperia

57

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Small cephalic vesicle of cooperia

58

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Short stumpy spicules of cooperia

59

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Bell shaped buccal cavity of Chabertia

60

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Unilaterally restricted cephalic vesicle of oesophagostomum

61

What pathogenic features are characteristic of Trichostrongylus axei?

  • L4/5 developing in mucosa - black scour
  • Sub-epithelial tunnels
  • Villous atrophy
  • Haemorrhage
  • Oedema
  • Diarrhoea

 

62

What is the morphological difference between eggs of Nematodirus battus and filicollis?

Battus - brown and parallel sides

Filicollis - clear and rounded sides

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63

Outline the lifecycle of Nematodirus battus.

Similar to cysthostome lifecycle - L4 burrow into SI mucosa

PPP=15 days

64

Whic trichostrongyle species are impicated in primary PGE?

Telodorsagia circumcincta

65

Which trichostrongyloidae are implicated in secondary PGE?

Haemonchus contorus

Trichostrongyloid axei

Nematodirus battus

Cooperia

66

Telodorsagia circumcincta is anagolous with what cattle species of parasite?

Ostertagia ostertagia