Nematode and cestode infections in sheep Flashcards
What are current problems with parasite control in sheep?
- Drug resistance
- Climate change
- Parasites - large genomes
What are common nematode infections in sheep?
- Nematodirus battus
- Teladorsagia circumcincta
- Trichostrongylus vitrinus
- Haemonchus contortus
- Dictyocaulus filaria
How do worms cause disease?
- Damage lining of guts
- Remove nutrients
- Remove blood
- Host immune response
What are clinical signs of nematode infection?
- Reduced appetite
- Poor weight gain
- Diarrhoea
- Anaemia
- Death
What are the disease caused by nematodes?
- Nematodirus battus - acute severe diarrhoea + death in lambs 6-12weeks
- Teladorsagia - type 1 lambs first graing season mid summer
-type 2 yearlings in winter months - Trichostronygus - black scour
- Haemonchus contortus - adults + lambs, acute regeneratuve anaemia + bottle jaw
What is the nematode life cycle?
- L1 + L2 live in faeces
- L3 infective stage - migrates to pasture
- Develops to eggs in sheep - 16-21days
When do different species of worm peak?
- Teladorsagia - early summer
- Trichostrongylus - late summer / autumn
- Haemonchus - mid spring, late autumn
What is hypobiosis?
L3 late autumn early winter over winter period interupted development L4 stage inside sheep.
◦ Teladorsagia- clinical disease scouring and weight loss in yearling sheep
◦ Pasture contamination in spring and early summer
◦ Main way Haemonchus survives winter
How can you increase risk of resistance?
- Treatment frequency
- Proportion of population exposed to treatment in refugia
- Under dosinng
- Biosecurity - new strains
How can you test for anthelmintic resistance?
- FECRT
When should you worm adult sheep?
- Treat at lambing time - to reduce pasture contamination for lambs - leave portion untreated (Fit singles)
- Treat thin ewes at tupping time
What are tapeworms found in sheep?
- Monezia
- Taenia hydatigena
- Taenia ovis
- Taenia multiceps
- Echinococcus granulosus