Trematodes Flashcards
What are the hosts of liver fluke/fasciola hepatica?
DH = cattle, sheep, horses, rabbits, humans - zoonotic
IH = galba truncatula snail
What is the PPP of liver fluke in the ruminant?
12 weeks
Outline the lifecycle of liver fluke.
- Eggs pass in faeces of DH
- 9 days to release mobile miracidia
- Must find snail within 3 hours
- Penetrates snail with enzymes
- Develops into sporocyst
- Redia emerge
- Cercaria (with tail) leave snail
- Swim in water to find grass
- encyst to become infective metacaria
- DH ingests
- Migrate and feed on liver
- Liver fluke matures in bile duct
How does liver fluke evade the immune system?
Glycocalyx - rapidly shed and replaced. In presence of antibody, shedding is accelerated. Disturbs eosinophils.
Cathepsin - aids migration and prevents antibody mediated attachment of oesinophils to parasite surface
What can liver fluke increases susceptibility to?
Black disease
Salmonella dublin
Describe acute fasciolosis from liver fluke.
- 2-6 weeks after ingestion
- Hepatic damage due to migration and feeding larvae
- Sudden deaths in sheep from Autumn to early winter
- Haemorrhage
- Anaemia
Describe chronic fasciolosis.
- 4-5 months after ingestion
- Most common
- Early spring
- Anaemia
- Liver becomes fibrous
- Bile ducts inflamed
Describe the epidemiology of liver fluke.
- The mud snail likes wet boggy areas at 15-22 degrees C, stopping and hibernating below 5 degrees C.
- Summer infection of snail = clinical disease following spring
- Winter infection of snail = clinical disease in autumn - less common
How is fasciolosis diagnosed?
Faecal egg count
Serological test
Presence of snail habitat
History on farm
How can fasciolosis be controlled and what are the disadvantages of each method?
Drainage of boggy area - impact biodiversity
Fencing off boggy areas - unpopular
Fluke anthelmintics - resistance, not allowed in lactating cattle
Describe the trematode anatomy.
Adults have mouth surrounded by oral sucker, both male and female sexual organs.
What is the name of the rumen fluke?
Calicophoron daubneyi
What are the hosts of rumen fluke?
DH = cattle and sheep
IH = galba truncatula
What are the clinical signs of rumen fluke?
Haemorrhagic diarrhoea
Anorexia
Severe scour
What are the risk factors of rumen fluke?
Immature flukes in the duodenum are often fatal in young. Damage intestinal mucosa (plug feeders).
Adult flukes in rumen = non-pathogenic
