PGE in sheep Flashcards
What are the 3 major parasitic species contributing to PGE?
- Teladorsagia circumcincta
- Trichostrongylus spp
- Cooperia spp
Where are o Trichostrongylus axei found?
Abomasum
Describe the morphology of Trichostrongylus spp
- very small (4-7mm)
- fine worms
- smallest of the GI nematodes found in the abomasum
- adult worms have a ‘notch’ = excretory pore, usually distinctive at the head end
How can a male and female Trichostrongylus be identified?
Head end is the same with excretory notch
- Female = vulval flap absent, simple tail, fewer than 12 eggs seen in uterus
- Male = tail end has a bursa with spicules coming out of the cuticle
Give the key points of a Trichostrongylus life cycle
- Hypobiosis
- L3 over winter
- Next generation of L3 develop on pasture over the summer
- 3 weeks pre-patent period
Give the key points of the pathogenesis of Trichostrongylus
- Larvae (L4 and L5) develop deep in mucosa
- Villous atrophy
- Haemorrhage: nature of larvae
Which species are affected by Cooperia spp?
Cow and sheep
What makes Cooperia a ‘dose defining species’?
Less susceptible to anthelmintics than other trichostrongyle nematodes
Describe the key points of Cooperia pathogenesis
- generally a mild pathogen
- can affect weight gain
- diarrhoea
- heavy infections lead to catarrhal enteritis, villous atrophy and oedema of intestinal mucosa
What 2 intervention methods can be used in the pre-parasitic stages?
- Removal of faecal matter to remove the parasitic environment (not practical in ruminant species)
- Grazing management
What are the 3 intervention methods used for the parasitic stages in the host?
- Anthelmintics
- Vaccinations (only available for H.contortus)
- General mediated host resistance
What is a ‘clean pasture’?
Not been grazed by sheep for the previous 12 months
What is a ‘safe pasture’
Used the previous year but safe by beginning of June
