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Liver fluke

Fasciola hepatica, or Liver Fluke, is a leaf-shaped, trematode parasite that lives in the bile ducts of the infected host, such as sheep, cattle or, under unusual circumstances, people.


Liver Fluke Life Cycle

Fascioliasis is a parasitic infection typically caused by the trematode parasite Fasciola hepatica, also known as the Liver Fluke. The lifecycle of the fluke commences once the miracidia (the first cycle stage of the fluke) hatches from an egg, passed through the bile duct and found in the faeces of the infected animal. Once hatched, the young fluke must find an intermediate host, for this, it invades the Galba truncatula (mud snail). The miracidia only has a few hours to do this before it dies. Once the suitable host has been spotted, the miracidia invades the snail and commences its second life cycle stage, known as sporacyst. From here, two more developments occur, the sporacyst undergoes massive multiplication into thousands of larval forms called redia and, subsequently, cercariae over a period of months.

The hot summers from May to July are typically when snail populations grow rapidly. Conversely, it is the rainfall that enables to adult fluke to shed from the snail back into the pastures of the field. We can infer, then, that it is the wet summers where infestations of liver fluke are far more likely to occur, particularly in areas of the country where there is high rainfall and when temperatures exceed 10ºC, such as conditions from May to October in the UK and Ireland.

Once the fluke has returned to the pasture as a cercariae (now in its fourth stage of life) they swim to a convenient part of grass for animals to eat. While waiting, they form around themselves a cyst for protection against adverse weather conditions. Meanwhile, grazing animals pass by and ingest the encysted metacercariae, which un-coat in the stomach and penetrate the intestine, travelling via the blood system to the liver.

For the next ten to twelve weeks the fluke (now in its final, adult stage) tunnels through the internal tissue of the animal, causing considerable damage, until it reaches the liver. Once here, the adult fluke lays eggs that are passed out into the pasture through the faeces’ of the infected animal, beginning the cycle again. 


The Liver fluke is a helminth parasite that infects the liver of both cattle and sheep, but it can also infect other species of ruminants, in rare cases it can affect humans too. Adult fluke are 2 to 3 cm in size and live in the bile ducts, laying eggs which enter the host’s intestinal tracts that are then passed through onto the pasture. The eggs hatch and invade a specific species of snail, Galba truncatula.

Once ingested, evidence of the infection can be detected within 10-12 weeks. The whole cycle takes about 18-20 weeks.

Liver Fluke Symptoms

Liver Fluke in Sheep

The pathogen is most prominent in sheep and is classed as either acute or chronic.

Acute cases are caused by massive numbers of migrating flukes from the stomach to the liver. The blood loss incurred by the sheep, or secondary infection from the damaged to the liver by clostridial bacteria(Black Disease) can, in extreme cases, cause sudden death.

Chronic cases result from prolonged intake of metacercariae, symptoms will most commonly show in progressive loss of bodily conditions that can result in the death of the infected sheep. Symptoms include:

  • Weight loss
  • Anaemia
  • Bottle Jaw
  • Diarrhoea
  • Constipation
  • Poor fleece condition

Liver Fluke in Cattle

Like sheep, the disease in cattle is seen as either acute or chronic.

Acute cases are less likely in cattle due to them having larger livers. Cases in cattle, then, are more likely to be chronic cases.

Chronic cases, like in sheep, result from prolonged intake of metacercariae and symptoms show in the progressive loss of bodily conditions:

  • Bottle jaw
  • Reduced fertility
  • Livers trimmed or condemned at abattoir
  • Anaemia
  • Terminal diarrhoea
  • Poor fertility
  • Weight loss
  • Reduced milk yields (Dairy cows)


Before seeking treatment, ensure diagnosis is correct. If in doubt consult a health care professional. Correct diagnosis is integral in the treatment of the parasite.

Treatment for Liver Fluke

It is important to diagnose the stage of liver fluke correctly in order to treat the condition effectively. All flukicideshave either milk-withholding effects or are prohibited entirely from use on animals producing dairy for human consumption.

Oral triclabendazole is typically regarded by health professionals as the closest ideal to treating all stages of liver fluke: acute, subacute and chronic, in cattle and sheep.

Endofluke 10%, is the ideal oral solution for the treatment of all stages of liver fluke and is approved for use in dairy cattle from 48 days after calving. Endofluke comes in three sizes, depending on your needs:

You can also purchase the Applicator for Sheep or Doser for Cattle separately.

 Similarly, Endospec 2.5%, or Albex 2.5% will control internal infestations of adult liver fluke in cattle and sheep. Both of these solutions uniquely contain anthelmintic and is ovicidal (effective at killing the eggs of the parasite in faeces, reducing pasture contamination).

Endospec 2.5% can be purchased in either:

Endospec 10%, as a separate solution to Endospec 2.5%, is also available and contains a stronger dose of albendazole – the preventative that keeps worm larvae from hatching in the bowel.

Endospec 10% can be purchased in either:

 Albex 10% can be purchased either in:

Albex 2.5% SC, as a separate solution to Albex 10%, is also available in multiple sizes and contains additional nutritional supplements:

 If targeting a sheep or cattle specifically, we recommend Tribex 5% for Sheep2.2 litres or 5 litres.

Alternatively, for cattle, see Tribex 5% for Cattle – 2.2 litres or 5 litres. Both solutions contain triclabendazole and are highly effective against all stages of Liver fluke.

A drencher is also available for either Sheep or Cattle, should you need it.

 Finally, if targeting the mature stages of liver fluke individually in beef and non-lactating dairy cattle, we suggest Bimectin plus, another broad spectrum anti-parasitic drug that is effective a treating a wide range of internal and external parasitic infections. It is available in:

It is good practise to restrict cattle access to snail habitats when possible.


Fasciola hepatica, or Liver Fluke, is a leaf-shaped, trematode parasite that lives in the bile ducts of the infected host.

The adult fluke passes eggs through the bile ducts of the infected animal into the faeces which land on the pasture. The eggs hatch in warmer temperatures, wherein the young fluke scurries to find intermediary host, the mud snail.

After some time, during wet summers, the snail shed the adolescent fluke, who swims to a nearby plain of grass and waits to be ingested by grazing animals.

Once in the stomach, the fluke tunnels to the liver, causing acute cases of fascioliasis, sometimes killing the animal. Over ten to twelve weeks, the conditions develops, chronic illness occurs, affecting the bodily conditions and functions of the animal. The animal withers away, the fluke lays eggs and begins the process again.

The pathogen is most prominent in sheep but can still be highly damaging to cattle and other ruminants. After diagnosis, appropriate treatment must be sought. A recommended flukicide containing triclabendazole is necessary. For reduction in pasture contamination, an ovicidal product is recommended to kill eggs before they hatch.

Strategic flukicide treatment, alongside correct pasture management will yield the best results when trying to control the outspread of liver fluke.