PGE

Teladorsagia and parasitic gastroenteritis. 

Common worms in the enteric system of sheep and cattle;

Abomasum:

• Haeomonchus Contortus.
• Ostertagia/teladorsagia. 
• Trichostrongylus Axei.

Small Intestine:

• Nematodirus.
• Trichostrongylus spp.
• Cooperia. 

Colon:

• Chabertia- strongyloidea. 
• Ophagostomum. 
• Trichuris- trichuroidea. 

Parasitic Gastroenteritis

• Diahorrea in lambs again but this time in late summer, so not between April-June as in Nematodirus, but between AUG-SEP. 
• Teladorsagia, trichystrongylus and cooperia spp.

Teladorsagia

• Similar to ostertagia in response but the inflammatory response exacerbated.
• Severity depends on:

1. Nutrition of sheep.
2. Concurrent infection.
3. Development of immune response.

• The main source of pasture contamination this time is the EWE (nematodirus has the lamb to lamb cycle with negligible ewe involvement). 
• Peri-parturient rise- around lambing time the ewe experiences decreased ummunocompetence.      This means that the hypobiosed larvae are reactivated (remember this is the EL4 stage, and in ostertagia this trigger was a rise in ambient temperature, this time the trigger is decrease immunity). 
• The eggs are shed onto pasture by the ewes in spring. There is a flush of L3 on the pasture in July similar to ostertagia and disease in AUG-SEP-> same as ostertagia. 

Trichostrongylus Axei

• Contributes to PGE. 
• Disease in its own right= Black scour. 
• Larvae develop L4-L5 deep in the mucosa (rather similar to nematodirus). They create however, sub-epithelial tunnels. This results in villous atrophy, haemorrhage, oedema and diarrhoea. This gives rise to weight loss & poor skeletal growth.

Cooperia

• Component of PGE. Less susceptible to anthelmintics- so is the dose defining species. 

Facts I forgot. PPP= 3 weeks. Trichostrongylosis (black scour) occurs autumn/early winter in lambs. 
Cooperia exacerbates ostertagiosis.