Fluke has a significant impact on the UK agricultural economy through sheep deaths, decreased production, poor fertility and liver rejections at abattoirs. The risk that fluke presents is highly determined by the climate. With increasing temperatures and wetter weather, the risk is ever rising and has been over the last 10 years.

Fluke requires two hosts for its lifecycle to be completed, one is the mud snail and the other is cattle/sheep. The mud snail is found in muddy, wet areas, making the north a perfect habitat!

The fluke lifecycle, outside of the sheep, is very dependent on temperature. The warmer and wetter the weather the more rapid the development of the parasite and the higher the risk. Development of fluke within the snail usually occurs between May and October and if the weather conditions are correct, the infective cyst stage is released onto pasture during August, September and October.

As sheep ingest the cyst form of fluke from the pasture, the parasite hatches in the small intestine and migrates across the gut to the liver. This immature form of fluke migrates across the liver causing tissue damage and bleeding as it moves and feeds until it eventually reaches the bile ducts in its adult form.

How can fluke affect my flock?

There are three manifestations of fluke which are acute, sub-acute and chronic. The severity of the disease depends on a number of factors including; the species affected, the time of the year, the number of fluke ingested and the time period over which they were ingested. Acute disease is more common in sheep and usually occurs after a warm, wet summer as a result of them ingesting large numbers of immature fluke.

Diagnosing Liver Fluke

Due to the increasing emergence of resistance to flukicides, it is important that fluke is diagnosed prior to treatment. There are many flukicides available however they vary in which stage of fluke they can treat, with many flukicides being effective against adult fluke but fewer against immature fluke. The table below indicates the different tests available. The results of these tests help us to advise you on the most suitable product to use as a treatment as well as allowing us to provide advice on how to minimise the risk of fluke going forwards.