Tapeworms of ruminants + parasites detected at the abattoir Flashcards
What parasites are detected at the abattoir?
- Tapeworms of sheep
- Tapeworms of cattle
- Lungworms of sheep
- Liver fluke (F. hepatica) infections of sheep and cattle
- Tapeworms and nematodes of pigs
What are the characteristics of cestodes/tapeworms?
- Adult worms are segmented
- Generally considered less pathogenic
- Each proglottid surrounded body wall called tegument
- Active structure through which tapeworms ingest food
- Characteristic eggs – thick embryophore, hexacanth embryo,
~40μm in diameter
What are the different types of metacestodes?
- Cysticercus – single evaginated protoscolex
- Coenurus – complex, several protoscolices
- Cysticercoid – microscopic, single protoscolex, found in invertebrate intermediate host
- Hydatid – highly complex, numerous protoscolices, potential for metastasis
What is the general cestode life cycle?
Definitive host
* Adults in small intestine
* Proglottids break off
* Eggs/proglottids shed in faeces
* Eggs immediately infective
Intermediate host
* Eggs eaten by intermediate host
* Metacestode develops
* Metacestode eaten by definitive host
* Adult tapeworm develops in small intestine
For what cestodes are sheep the intermediate hosts?
- Taenia ovis (cysticercus in muscles)
- T. hydatigena (cysticercus in peritoneum)
- T. multiceps (coenurus in brain)
- Echinococcus granulosus (hydatid cyst)
For what cestode are cows the intermediate host?
- Taenia saginata (cysticercus in muscles)
What is Taenia ovis?
how is it controlled?
- Cysticercus in muscles and heart – sheep measles
Vaccine + education
What is Taenia hydatigena? what does it cause?
- Cysticercus migrates through the liver of sheep
-heavy infestations = hepatitis + death in young lambs
What is Taenia multiceps? What does it cause?
- Coenurus/Gid cyst in brain and CNS
-neuro complications = visual defects, circling, weight loss - no Tx
What is Echinococcus granulosus
- Hydatid cyst in liver and lungs of sheep and cattle
- no pathogen significance in cattle/sheep
How do you control tapeworms?
Praziquantel treatment of dogs to remove adult tapeworm
-break the cycle by controlling access to intermediate host
What is Taenia saginata?
What is the control?
Beef tapeworm
* Metacestode in muscle of cattle - cysticercus
Control = * Meat inspection (heart, masseters)
* Cooking or freezing meat
* Sewage disposal
What is Moniezia spp?
- Common - small intestine of sheep, cattle and goats
- Long tapeworm (~ 2m +)
- Metacestode stage (cysticercoid) develops in oribatid mite
- Occasional clinical signs: unthriftiness or diarrhoea
What is Muellerius capillaris?
Lungworm of sheep
non pathogenic in sheep - highly pathogenic in goats
ppp = 25-28d
