Parasitic Liver disease

Question 1

What disease do Fasciola Hepatica and Fasciola Gigantica cause?

Answer 1

Fasciolosis
they can also infect humans

Question 2

What is the infective life stage of fasciola?

Answer 2

metacariae

Question 3

What is the amphibious intermediate host of f.hepatica?

Answer 3

Galba trunculata

likes slightly acidic wet mud

Question 4

When are metacariae on pasture for summer infection?

Answer 4

Between August and October

Question 5

When are metacariae on pasture for winter infection?

Answer 5

Between May and June

Question 6

How may humans become infected with metacariae?

Answer 6

Infection via consumption of freshwater veg/ infected water
it requires an animal reservoir to maintain an infection in humans

Question 7

What does acute infection in sheep look like?

Answer 7

• 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

Question 8

What does subacute infection in sheep look like?

Answer 8

• 500-100 adults, low FEC
• Enlarged liver, necrotic/ haemorrhagic tracts
• Rapid weight loss/ anaemia, submandibular oedema, ascites in some cases

Question 9

What does chronic liver parasites in sheep look like?

Answer 9

• 200+ adults, between Dec-April, FEC of above 100
• Most common form
• Progressive weight loss and anaemia
• Submandibular oedema, ascites
• Effects production

Question 10

What is the consequence of infection in cattle?

Answer 10

• 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

Question 11

What are the economic consequences of liver fluke in cattle?

Answer 11

• Losses to the livestock and dairy industry worldwide
• Costs around 40-300 million to the UK cattle industry

Question 12

How would you diagnose liver fluke in cattle?

Answer 12

• Clinical signs
• Seasonal occurence
• PM examination of the liver
• Haematological testing
• Exam faeces for fluke eggs
• Plasma
• Copro-antigen ELISA

Question 13

How would you control fasciolosis?

Answer 13

• Assess the fasciolosis risk on the farm
• Meterological forecasting
• Grazing and environmental managemnt
• Flukicide treatment
• quarantine any incoming cattle or sheep

Question 14

How would you manage the grazing/ enviironment?

Answer 14

• 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

Question 15

What are the two models of fluke forecasting?

Answer 15

1. Ground surface wetness-> summer infection of snails
2. ‘Wet-day’ forecast, number of wet days over summer months

Question 16

When do you use flukicide treatment?

Answer 16

• Treatment is commonly used as part of control programmes
• prevents disease and pasture contamination
• Risk assesment is required

Question 17

What is the most common flukicide treatment?

Answer 17

Triclabendazole

Question 18

What is the four-point plan for pasture contamination?

Answer 18

• Prevents pasture contamination (Spring)
• Test for resistance (Summer)
• Avoid wet pasture, test and treat juvenile fluke (Autumn)
• Hosuing, test before treatment (Winter)

Question 19

What is a copro-antigen ELISA?

Answer 19

detects the digestive enxxymes found in fasciola hepatica

Question 20

What is Dicrocoelium lanceolatum?

Answer 20

Trematode parasite of ruminants, deer and rabbits
Adults found in the bile ducts of the liver
High prevalence in parts of Europe

Question 21

What is the PPP of dentriticum (lancerolatum)?

Answer 21

10-12 weeks

Question 22

What are the clinical signs of dentriticum?

Answer 22

• Infected livers are normal and clinical signs are absent
• Heavy infection = fibrosis of bile ducts and cirrhosis
• Anaemia, oedema, emaciation, reduced wool growth

Question 23

How would you diagnose dentriticum?

Answer 23

eggs in faeces and PM examination for adult fluke

Question 24

How may you control dendriticum?

Answer 24

Eggs can survive for months on pasture- reservoir of infection
Control depends on regular anthelmintic treatment

Question 25

What is the definitive host for taenia hydagitena?

Answer 25

Dogs, foxes, weasels, stoat, hyena, wolf

Question 26

What is the intermediate host of taenia?

Answer 26

Sheep, Pig, Goat, Cow

Question 27

What is the location of the Taenia metacestode?

Answer 27

Peritoneum, liver

Question 28

How do dogs become infected with taenia from sheep?

Answer 28

• Dog consumes offal from the sheep carcass
• Adult tapeworm develops in the dog small intestine

Question 29

How does the taenia hydagitena intermediate host become infected?

Answer 29

Via grazing pasture that has become infected with dog faeces
* Oncospheres are carried via blood to the liver and migrate for 4 weeks
* they emerge onto the surface of the liver and attach to the peritoneum
* develop to a large metacestode over 4 weeks

Question 30

How do you diagnose/ control taenia?

Answer 30

• Emaciation and ascites may be present
• Heavy infection in lambs leads to death
• Diagnosis on meat inspection = larval cysts on organs, liver may contain haemorrhagic tracts

There is no treatment but you can control by disposing of ruminant carcasses and offal
deworm farm dogs