FA Trichostrongylidae Flashcards
Brown stomach worm is also known as…
Ostertagia ostertagi
In which area of the rumen would adult ostertargia be found?
Abomasum
Outline the morphological features of the adult Ostertagia.
1cm in length
Slender
Pink-brown
Fine cervical papillae - finger-like projections
Bursal spicules - male
Where in the abomasum would Ostertagia be found?
The gastric glands
Describe the pathologenic features of Ostertagia infection.
- Damages parietal cells
- Increase in pH to pH7
- Build up of pepsinogen
- No bacteriostatic effects of HCl
- Loss of cell-to-cell adhesion = plasma protein leakage (albumen)
- Pepsinogen transferred to plasma
- Replacement of parietal cells with undifferentiated epithelial cells - loss of abomasal function
What is the gross appearance of an ruminant abomasum affected by ostertagia?
Nodular hyperplasia of gastric glands
Describe the morphology of Ostertagia eggs.
- 90x45um
- barrel shaped
- undifferentiated morula
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
What is shown in this histo slide?
What are the consequences of this stage of OO lifecycle?
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
Describe Type 1 ostertagiosis.
July - September (August)
Large numbers of L3 ingested in July
Green watery diarrhoea
Usually dairy replacement heifers
Describe Type 2 ostertagiosis
Occurs due to simultaneous emergence of hypobiosed larvae from gastric glands after winter
- Acute
- Intermittent diarrhoea
- Anaemia
- Thirst
- High mortality
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
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)
Name the worms found in the large intestine of cattle and sheep.
- Chabertia spp
- Oesophagostomum spp
- Trichuris spp
COT
What factors are necessary for development of pre-parasitic stages of OO?
- Temperature > 10o
- Humidity/ rainfall - dispersal of faecal pat
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.
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)
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
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.
When is T2 ostertagiosis most likely to develop? Why?
Late winter- early spring.
When L5 simutaneously emerge from the gastric glands
What diagnostics are used to dx. OO?
Plasma pepsinogen levels are raised
Clinical signs
Grazing history
Dictyocaulus spp. are what type of worm?
Trichostrongyle
Name a species of Dictycaulus which occurs in sheep and goats in the tropic and sub-tropics.
Dictyocaulus filaria
Which species of Dictyocaulus causes respiratory disease in horses and patent infection in donkeys?
Dictyocaulus arnfieldi
Husk aka
Parasitic bronchitis
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
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
Describe the morphology of iL3 D. vivaparus.
Double sheathed - L1/2
Short/ stumpy
Contain food granules
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
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
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
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
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
Describe the vaccination used against DV.
Live attenuated - 1000 irradiated L3
Oral
2 x doses before turnout
Name a trichostrongyloid which affects lamb and is found in the small intestine.
Nematodirus battus
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
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
What is the pre-patent period of Nematodirus battus?
15 days
What is the infective stage of the lifecycle of Nematodirus battus?
L3 which has hatched from the egg
Which lifecycle stages are found within the egg of Nematodirus battus?
L1 - L3 (l3 hatches)
Describe the pathology of Nematodirus battus?
Developing l5 destroy mucosa
Effects: catarrhal enteritis, villous atrophy, disruption of fluid and nutrient absorption
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
What climatic conditions are required for development of Nematodirus battus larvae on pasture?
When is emergence of larvae often observed?
- Exposure to prolonged period of chill
- Exposure to mean day/ night temperature of 10oC
- Emergence around Spring
Which anthelmintic is N. battus NOT susceptible to?
Inj Macrocyclic lactones (moxidectin)
Instead use BZ or Imidaclopride
Lancet tooth of Haemonchus contortus
Large bursal cavity of Haemonchus contortus - large lateral lobes with Y dorsal lobes and rays
Intertwining gut and uterus of Haemonchus contortus
Cervical papillae of Haemonchus contortus
Short, unequal spicules of Trichostrongylus axei
Excretory notch of Trichostrongylus axei
Ovijector of Trichostrongylus axei - Holds and expels eggs from parasite
True or false
Ostertagia/ telodorsagia have cervical papillae?
TRUE
Long, thin spicules of Nematodirus battus
Fused at the tip!
Cephalic (bubble-like) vesicle (more prominent than cooperia)
Large eggs seen in the uterus of Nematodirus battus
Watch-spring appearance of cooperia
Small cephalic vesicle of cooperia
Short stumpy spicules of cooperia
Bell shaped buccal cavity of Chabertia
Unilaterally restricted cephalic vesicle of oesophagostomum
What pathogenic features are characteristic of Trichostrongylus axei?
- L4/5 developing in mucosa - black scour
- Sub-epithelial tunnels
- Villous atrophy
- Haemorrhage
- Oedema
- Diarrhoea
What is the morphological difference between eggs of Nematodirus battus and filicollis?
Battus - brown and parallel sides
Filicollis - clear and rounded sides
Outline the lifecycle of Nematodirus battus.
Similar to cysthostome lifecycle - L4 burrow into SI mucosa
PPP=15 days
Whic trichostrongyle species are impicated in primary PGE?
Telodorsagia circumcincta
Which trichostrongyloidae are implicated in secondary PGE?
Haemonchus contorus
Trichostrongyloid axei
Nematodirus battus
Cooperia
Telodorsagia circumcincta is anagolous with what cattle species of parasite?
Ostertagia ostertagia
