High liver fluke risk warning for south and west Scotland

A red warning for high risk of liver fluke has been issued for southern and western Scotland this week.

Animal health experts at the National Animal Disease Information Service (Nadis) have warned sheep and cattle farmers to watch for signs of liver fluke infection after a particularly wet July.

Despite dryer-than-average weather in south Wales and south-west England, July’s UK rainfall was 114% of the historic average.

See also: Q&A: Everything you need to know about liver fluke in cattle

Meanwhile, the average UK temperature was 16.4C in July, 1.2C above the 1981-2010 average. Such warm and wet conditions have allowed snails – the intermediate host of the liver fluke – to thrive. 

Three key signs of liver fluke are:

  • Rapid weight loss and fluid accumulation (eg bottle jaw)
  • General dullness, anaemia and shortness of breath
  • Sudden death in heavy infections

Rainfall and temperature data for August-October 2018 and May-June 2019 has led Nadis to issue the warning, with a moderate risk predicted for the rest of Scotland.

A moderate risk has also been forecast for Northern Ireland, Wales and western parts of England, with low risk forecast across eastern and central England.   

What to do

Nadis advises farmers to monitor for signs of disease and test for levels of infection in stock.


  • Post-mortem examinations can be used for a definitive diagnosis
  • Worm egg counts can be used to diagnose infection in individuals or groups of animals
  • Egg counts should not be relied upon for the diagnosis of acute disease


  • Triclabendazole is recommended for acute disease as this is the only product effective against adult and immature stages
  • A resistance test 21 days after treatment is recommended to monitor efficacy
  • Seek veterinary advice when drug failure is present and resistance is suspected
  • Follow Scops (Sustainable control of parasites in sheep) and Cows (Control of worms sustainably) guidelines when treating.

Grazing considerations

  • Mud snails are generally found in damp, muddy areas such as the borders of permanent water bodies
  • Pastures previously infected by fluke-infected sheep or cattle could be considered a risk.