Clinical aspects of liver fluke

Question 1

What climate is fluke seen?

Answer 1

• Warm + wet

Question 2

What is the life cycle of liver fluke?
(summer infection of snails)

Answer 2

• Spring early summer = eggs excreted from infected sheep / over wintered eggs
• Spring / summer = Miracidia infected snails
• Summer / autumn = Cercariae and metacercariae shed by snails
• Autumn / winter = disease in sheep

Question 3

What is the life cycle of liver fluke?
(winter infection of snails)

Answer 3

• Autumn = snails infected miracidium hibernate
• Late Spring = ceracariae metacercariae infect sheep
• Early Summer = Acute Disease in Sheep

Question 4

What are clinical signs of acute fluke disease?

Answer 4

• 2-6 weeks after ingestion of very
  large numbers metacercariae
• Sept- Dec
• Severe haemorrhage due to migration of immature stages through the liver
• Sudden death
• Weakness
• Pale
• Dyspnoeic

Question 5

What are clinical signs of chronic fluke disease?

Answer 5

• Blood feeding adults in the bile ducts
• Haemorraghic anaemia, hypoalbuminaemia
• Hepatic fibrosis and cholongitis
• Anaemia
• Weight loss
• Sub mandibular oedema
• Weight loss
• Enlarged liver
• Secondary clostridial infection
  Black’s Disease

Question 6

How is fluke diagnosed?

Answer 6

• History
• PM
• Clinical signs
• Faecal egg counts

Question 7

How is fluke treated?

Answer 7

• Triclabendazole = kills any stage but resistance
• No persistent activity - can get re infected immediately = treat and move to low risk pasture
• Closantel