Parasitic Liver disease Flashcards
What disease do Fasciola Hepatica and Fasciola Gigantica cause?
Fasciolosis
they can also infect humans
What is the infective life stage of fasciola?
metacariae
What is the amphibious intermediate host of f.hepatica?
Galba trunculata
likes slightly acidic wet mud
When are metacariae on pasture for summer infection?
Between August and October
When are metacariae on pasture for winter infection?
Between May and June
How may humans become infected with metacariae?
Infection via consumption of freshwater veg/ infected water
it requires an animal reservoir to maintain an infection in humans
What does acute infection in sheep look like?
- 1000+ fluke, mainly immature, no FEC
- Destruction of the liver parenchyma
- haemorrhage due to young fluke migration
- Sudden death or dullness, anaemia, dyspnoea, ascites and abdominal pain
What does subacute infection in sheep look like?
- 500-100 adults, low FEC
- Enlarged liver, necrotic/ haemorrhagic tracts
- Rapid weight loss/ anaemia, submandibular oedema, ascites in some cases
What does chronic liver parasites in sheep look like?
- 200+ adults, between Dec-April, FEC of above 100
- Most common form
- Progressive weight loss and anaemia
- Submandibular oedema, ascites
- Effects production
What is the consequence of infection in cattle?
- Generally chronic, loss of weight, condition and anaemia/ diarrhoea,
- acute disease is rare in the UK
- Low fluke numbers = subclinical effects, reduced milk quality and yield, reduced FCR’s, poor growth, liver condemnation
- Biliary hyperplasia, calcification of bile ducts, enlargement of the gall bladder
- Occurs in Winter/ early spring
What are the economic consequences of liver fluke in cattle?
- Losses to the livestock and dairy industry worldwide
- Costs around 40-300 million to the UK cattle industry
How would you diagnose liver fluke in cattle?
- Clinical signs
- Seasonal occurence
- PM examination of the liver
- Haematological testing
- Exam faeces for fluke eggs
- Plasma
- Copro-antigen ELISA
How would you control fasciolosis?
- Assess the fasciolosis risk on the farm
- Meterological forecasting
- Grazing and environmental managemnt
- Flukicide treatment
- quarantine any incoming cattle or sheep
How would you manage the grazing/ enviironment?
- Survey snail habitats
- Drainage
- keep animals off the wettest fields
- Fence off high-risk areas
- repair leaks from pipes and water troughs
- Housing strategy to remove them from high risk pasture
- Graze treated animals on ‘low-risk’ pasture
What are the two models of fluke forecasting?
- Ground surface wetness-> summer infection of snails
- ‘Wet-day’ forecast, number of wet days over summer months
When do you use flukicide treatment?
- Treatment is commonly used as part of control programmes
- prevents disease and pasture contamination
- Risk assesment is required
What is the most common flukicide treatment?
Triclabendazole
What is the four-point plan for pasture contamination?
- Prevents pasture contamination (Spring)
- Test for resistance (Summer)
- Avoid wet pasture, test and treat juvenile fluke (Autumn)
- Hosuing, test before treatment (Winter)
What is a copro-antigen ELISA?
detects the digestive enxxymes found in fasciola hepatica
What is Dicrocoelium lanceolatum?
Trematode parasite of ruminants, deer and rabbits
Adults found in the bile ducts of the liver
High prevalence in parts of Europe
What is the PPP of dentriticum (lancerolatum)?
10-12 weeks
What are the clinical signs of dentriticum?
- Infected livers are normal and clinical signs are absent
- Heavy infection = fibrosis of bile ducts and cirrhosis
- Anaemia, oedema, emaciation, reduced wool growth
How would you diagnose dentriticum?
eggs in faeces and PM examination for adult fluke
How may you control dendriticum?
Eggs can survive for months on pasture- reservoir of infection
Control depends on regular anthelmintic treatment
