Liver fluke

How do dogs become infected with liver flukes?

Infection with liver flukes occurs through the feeding of raw or insufficiently heated meat or fish that is contaminated with the larvae of the parasites. The large liver fluke has a complicated development cycle that involves several intermediate hosts. The eggs of the parasite are excreted in the feces of the final host (e.g. sheep, cattle, deer) and enter water bodies where they hatch into larvae. These larvae infect freshwater snails, in which they develop and multiply. Further larvae are then released from the snails, which attach themselves to aquatic plants. When a dog eats these plants or drinks water contaminated with them, it ingests the larvae. The larvae then migrate through the intestinal wall into the abdominal cavity and from there into the liver, where they mature into adult worms.

The small liver fluke has a similar life cycle, but its intermediate hosts are ants and not snails. The ants ingest the larvae of the parasite, which then influence their behavior. The infected ants climb onto blades of grass or other plants and get stuck there. When a dog eats or nibbles on these plants, it ingests the ants and thus the larvae. The larvae then enter the liver and bile ducts via the intestines.

What symptoms do dogs with liver flukes show?

The symptoms of a liver fluke infection in dogs depend on the type and number of parasites, the stage of the disease and the general condition of the animal. The most common signs include

• Loss of appetite
• weight loss
• diarrhea
• vomiting
• Jaundice (yellowing of the mucous membranes and skin)
• abdominal pain
• anaemia
• bleeding
• fever
• Accumulation of fluid in the abdomen (ascites)
• Enlargement of the liver
• Inflammation of the bile ducts
• gallstones
• liver failure

In some cases, neurological symptoms such as convulsions, paralysis or behavioral changes can also occur if the parasites enter the brain or spinal cord.

How is a liver fluke infection diagnosed in dogs?

The diagnosis of a liver fluke infection in dogs is based on the medical history, clinical symptoms, blood count, biochemical analysis and the detection of the parasites or their eggs in the feces or bile. Since the eggs are not shed continuously, several fecal samples may be necessary to confirm an infection. An ultrasound examination can also help to detect changes in the liver or bile ducts.

How is a liver fluke infection in dogs treated?

Treatment of a liver fluke infection in dogs consists of administering special deworming medication that kills the parasites. The active substances that are effective against liver flukes include praziquantel, albendazole or triclabendazole. Treatment usually takes several days and should be prescribed and monitored by a vet. In addition to deworming, it is also important to alleviate the symptoms and support liver function. Painkillers, anti-inflammatories, antibiotics, infusions, vitamins or liver protectors can be used for this purpose. In severe cases, surgery may also be necessary to remove gallstones or abscesses.

How can I prevent a liver fluke infection in dogs?

The best way to prevent liver fluke infection in dogs is to avoid raw or undercooked meat or fish that may be contaminated with the larvae of the parasites. Care should also be taken to ensure that the dog does not drink water from stagnant water or eat plants that have come into contact with infected snails or ants. Regular deworming can also help to prevent or detect an infection at an early stage.