Liver fluke infections have been increasingly found in donkeys in recent years. As with other worms, animals become infected while grazing. The liver fluke has a complex, indirect life cycle. A freshwater snail is necessary as an intermediate host. Because these snails can only survive in moist conditions, liver fluke infections are mainly found in donkeys that have grazed on wet, damp pastures. In pastures where sheep or cattle have grazed in the previous year, infections occur even more frequently. Liver fluke does not naturally occur on high sandy soils or well-drained fields. On the other hand, there is always a risk of infection in, for example, western pasture areas. Note that even a single wet corner or ditch with water can be a source of liver fluke infection.
The adult liver fluke lives in the bile ducts of the liver and produces characteristic eggs that are excreted with the manure. Depending on environmental temperature and the presence of water, a larva develops within 3 weeks, swimming in the water and actively seeking its intermediate host: a freshwater snail. The larva enters the snail and multiplies inside it. There, it develops further into the next stage, the so-called cercariae. These cercariae leave the snail and become infectious for the donkey. They are then called metacercariae, which can remain infectious for several months. After ingestion, the young larvae penetrate the intestinal wall and migrate to the liver, where they wander for several weeks before settling in the bile ducts. The entire cycle takes at least 4-6 months. Many donkeys naturally have resistance to liver flukes. Although donkeys can become infected, they are generally able to immobilize and eliminate the parasites effectively.
Due to their naturally high resistance, there are often no clear clinical symptoms. The symptoms are mostly nonspecific: weight loss, reduced appetite, a dull coat, anemia, diarrhea, or similar vague complaints. Young donkeys are more often infected than adults. Liver fluke infections are frequently found in donkeys that also carry many other gastrointestinal worms, such as strongyles or roundworms. Therefore, always have the manure tested if you suspect liver fluke.
Diagnosing liver fluke is not easy. Proper assessment of the factors that determine pasture contamination is very important. Therefore, actively monitor moisture, temperature, and previous grazing by ruminants. This history, combined with blood tests for liver enzymes, a fecal examination, and the clinical picture of the donkey, will lead to a probable diagnosis. If a fecal examination has been performed with a sufficient amount of manure and using the correct technique, the diagnosis can be confirmed by detecting liver fluke eggs. At Worm&Co, we use the modified Dorsman method. This test is qualitative, which means we can determine with certainty whether the donkey is infected or not. Because liver fluke infections are almost always found in donkeys with gastrointestinal worms, we always combine the liver fluke test with a regular worm test using the McMaster method. If you are also interested in having a liver fluke test done for your donkey, you can easily order a worm check kit on our website!
In the Netherlands, there are no registered products for treating liver fluke in donkeys. However, good results have been achieved with triclabendazole. Due to the widespread use of triclabendazole in sheep, many liver flukes have developed resistance to this drug. If a fecal test shows that your donkey is infected with liver fluke, we will provide you with a personalized treatment plan. This way, your donkey's health comes first and you avoid unnecessary deworming. Please feel free to contact our team if you have any questions; we are happy to help you further.
NL
DE
FR