Liver Flukes in Cats: Symptoms, Causes, and Treatment

What Are Liver Flukes in Cats?

Liver flukes are trematode parasites that infect many types of animals, including cats.

While several types of liver flukes exist, Platynosomum concinnum is the most common one affecting cats. It’s mostly found in hot, humid climates.

Between 15% and 85% of cats living in geographic areas where liver flukes are most common—such as Florida or Hawaii—will become infected.

Cats get liver flukes after they eat another infected animal, such as a lizard. Liver flukes move to the cat’s liver, gallbladder, and bile ducts, where they cause significant damage and inflammation (swelling).

Cats allowed outdoors are more commonly diagnosed with liver flukes because they hunt and eat infected animals.

Many cats with liver flukes are asymptomatic, while others show concerning symptoms, such as jaundice, vomiting, and weight loss. If a cat shows any of these signs, they should be brought to a veterinarian right away for the right diagnosis and treatment.

With treatment, a cat’s outlook is generally good, and most cats recover fully from liver fluke infections.

However, if left untreated, liver flukes can make cats very ill and may cause liver failure or death.

Symptoms of Liver Flukes in Cats

Many cats can control liver fluke infections and therefore have no symptoms. However, when larger numbers of liver flukes are present, symptoms are more common.

Because of the longer life cycle of liver flukes, symptoms generally start between two and four months after infection and may include the following:

• Decreased appetite

• Lethargy

• Fever

• Jaundice

• Vomiting

• Diarrhea

• Distended (enlarged) abdomen

• Weight loss

Causes of Liver Flukes in Cats

Liver flukes have an indirect life cycle, which means they need intermediate hosts to survive and infect cats.

First, liver fluke eggs (found in animal stool) are eaten by a snail and turn into sporocysts in the snail’s body. These sporocysts are released by the snail and eaten by other host animals, such as lizards and frogs, thereby infecting them.

Cats then become infected with liver flukes when they hunt and eat an infected host, such as a frog. After they are eaten, liver flukes leave the cat’s intestines and travel to the liver, gallbladder, and bile ducts, where they grow and reproduce. The eggs they make are later shed in the cat’s stool.

Because of the liver fluke’s complex life cycle, it takes about three months for cats to shed liver fluke eggs. Once the eggs are shed, they can be eaten again by snails, and the life cycle restarts.

How Veterinarians Diagnose Liver Flukes in Cats

Diagnosis can be difficult, so veterinarians use a combination of tests to confirm liver flukes in cats.

First, a veterinarian will start with a physical exam to find any obvious abnormalities, such as a distended belly or jaundice. A veterinarian will also ask specific questions, such as when symptoms started and if your cat spends any time outdoors.

Diagnostic tests are helpful to figure out the underlying cause of the cat’s symptoms and may include the following:

• Fecal sedimentation: A small sample of feces is combined with water, which allows liver fluke eggs to settle at the bottom so they can be seen under a microscope. Eggs are shed off and on, so this test has the potential for false negatives.

• Blood work: A small sample of blood is used to check red and white blood cells, platelets, and internal organ function, including the liver.

• Abdominal ultrasound: Ultrasound is a special test using sound waves is used to look at the liver, gallbladder, and bile ducts to find damage caused by liver flukes.

• Liver biopsy: A sample is taken from the liver to see changes, such as inflammation or fibrosis, related to liver fluke infections. This test requires general anesthesia and surgery to collect a sample; therefore, it may not be recommended in all patients, such as those that are critically ill or with other health issues.

Treatment of Liver Flukes in Cats

Treatment for liver flukes in cats includes anti-parasitic medications, such as praziquantel or fenbendazole. Getting rid of all the liver flukes may take several courses of treatment.

Other medications that may be prescribed include the following:

• Corticosteroids, such as prednisolone, to reduce inflammation

• Antibiotics, such as amoxicillin, to prevent secondary bacterial infections

• Anti-nausea medications, such as maropitant, to reduce nausea and vomiting

• Bile acids, such as ursodiol, to increase bile flow through the bile ducts

• Antioxidants, such as vitamin E, to protect the liver

• Supplements, such as SAMe, to promote liver health

In severe infections, cats may be very ill and need hospitalization and supportive care.

Treatment that may be given includes intravenous (IV) fluid therapy, medication, and feeding support, such as a feeding tube or special diet.

Cats with several liver flukes may have occluded (blocked) bile ducts and may need surgery to fix the problem.

Recovery and Management of Liver Flukes in Cats

With the right treatment, most cats fully recover after mild infections. However, in chronic or severe cases that have been left untreated, the condition can be fatal.

Even after treatment, it can take two months for cats to stop shedding liver fluke eggs. Because eggs continue to be shed, re-infection is a concern if a cat is exposed to the same environment he was in before getting infected.

Pet parents should keep their cat indoors and give all medications exactly as prescribed during the treatment period. They should also ensure their cat attends any follow-up appointments to confirm the infection has been cleared up.

Liver fluke infections can also increase the risk of liver or pancreatic carcinomas in cats due to damage and inflammation from chronic infections. Your veterinarian may recommend keeping an eye on the liver, gall bladder, and bile ducts.

Prevention of Liver Flukes in Cats

Because liver flukes are picked up by cats when they hunt and eat other small animals, keeping your cat indoors will prevent them from becoming infected. Keep your cat on monthly parasite protection with products containing praziquantel, such as NexGard® COMBO.