What Are Liver Flukes?
Liver flukes are parasitic flatworms that infect the liver, gallbladder, and bile ducts of humans and other animals. These infections are known as liver fluke disease or fascioliasis, depending on the species involved. While liver fluke infections are more common in parts of Asia, Africa, and South America, cases can also occur in the U.S. and Europe.
This article will help you understand what liver flukes are, how they affect your body, and what you can do to prevent or manage them.
What are liver flukes?
Liver flukes are a group of parasitic worms that live in the bile ducts or liver tissue of their host. There are several species, but the most common types that infect humans include:
-
Clonorchis sinensis (Chinese liver fluke)
-
Opisthorchis viverrini
-
Opisthorchis felineus
-
Fasciola hepatica (sheep liver fluke)
-
Fasciola gigantica
These parasites are part of a group called trematodes. They have complex life cycles involving multiple hosts.
How do you get infected with liver flukes?
In most cases, liver fluke infections happen when you eat:
-
Raw or undercooked freshwater fish
-
Contaminated water plants like watercress
-
Food prepared with infected water
You can't get liver flukes from another person directly. The parasite needs time to develop in freshwater snails and fish before it can infect a human.
What happens inside the body?
Once inside your digestive tract, liver fluke larvae travel to your liver through the bile ducts. There, they mature into adult worms and may live for years.
As they live and feed, they cause:
-
Inflammation
-
Scarring
-
Blockages in the bile ducts
-
Liver damage over time
Long-term infections may increase the risk of cholangiocarcinoma, a type of bile duct cancer.
Symptoms of liver fluke infection
In the early stages, liver fluke infections may not cause any symptoms. When they do appear, they vary depending on the type of fluke and the stage of infection.
Acute phase symptoms (early stage)
-
Fever
-
Abdominal pain (especially in the upper right side)
-
Nausea or vomiting
-
Diarrhea
-
Fatigue
-
Enlarged liver
Chronic phase symptoms (long-term)
-
Ongoing right upper abdominal discomfort
-
Jaundice (yellowing of the skin and eyes)
-
Itching
-
Loss of appetite
-
Weight loss
Not everyone will experience severe symptoms. Some people may carry the parasite for years without knowing it.
How are liver flukes diagnosed?
If your doctor suspects a liver fluke infection, they may order:
-
Stool tests to look for parasite eggs
-
Blood tests for eosinophilia (a type of white blood cell)
-
Liver function tests to detect liver damage
-
Ultrasound or CT scan to check the liver and bile ducts
-
Endoscopy in more complex cases
Early detection is important. If you're experiencing symptoms and have eaten raw fish or traveled to endemic areas, tell your doctor.
How are liver flukes treated?
Treatment depends on the species of fluke. Common medications include:
-
Praziquantel (for Clonorchis and Opisthorchis)
-
Triclabendazole (for Fasciola infections)
These medications usually work well, especially when the infection is caught early. In chronic or advanced cases, further care may be needed to manage liver damage.
Can liver flukes be prevented?
Yes. The best way to avoid liver flukes is to change how you handle and prepare food.
Prevention tips
-
Avoid eating raw or undercooked freshwater fish or snails
-
Wash vegetables thoroughly, especially if grown near freshwater sources
-
Drink safe, treated water
-
When traveling, avoid food from unsafe or unknown sources
These steps are especially important in places where liver flukes are common, such as Southeast Asia and parts of Latin America.
Are liver flukes dangerous?
They can be. Liver flukes aren't always life-threatening, but long-term infections can cause serious health issues, including:
-
Bile duct inflammation
-
Gallbladder disease
-
Liver fibrosis (scarring)
-
Increased risk of bile duct cancer
That's why it's important to get tested and treated if you suspect a liver fluke infection.
Where are liver flukes most common?
Liver fluke infections are more common in areas where people eat raw or undercooked freshwater fish. This includes:
-
China, Korea, Vietnam, Thailand (Clonorchis sinensis)
-
Russia and Eastern Europe (Opisthorchis felineus)
-
South America, Africa, Middle East (Fasciola species)
While rare, liver fluke infections can occur in the U.S. among travelers, immigrants, or people who eat imported raw fish.
How long do liver flukes live in the body?
Depending on the species, liver flukes can live 5 to 30 years inside the human body. This is why some people carry them for decades without realizing it.
The longer the worms stay in your body, the more damage they can do.
Complications from untreated infections
If liver flukes are not treated, they can lead to:
-
Blocked bile ducts
-
Infections in the bile ducts (cholangitis)
-
Gallstones
-
Pancreatitis
-
Permanent liver damage
-
Cancer of the bile ducts
These complications are rare in early infections but become more likely over time.
Liver flukes and cancer risk
Infections with Clonorchis sinensis and Opisthorchis viverrini have been linked to a higher risk of cholangiocarcinoma, a rare but aggressive bile duct cancer. According to the World Health Organization, these parasites are classified as Group 1 carcinogens, meaning there's strong evidence they cause cancer in humans.
How common are liver fluke infections?
Globally, over 35 million people are infected with liver flukes, with the highest rates in Asia.
In the United States, cases are rare but can occur due to:
-
Travel to endemic countries
-
Eating imported or locally caught raw fish
-
Exposure to contaminated water
Do liver flukes affect animals?
Yes. Liver flukes infect livestock like cattle, sheep, and goats. Infected animals may show symptoms like poor growth, weight loss, or reduced milk production.
These infections can be costly for farmers and also increase the risk of spreading parasites to humans through the food supply.
How is liver damage monitored?
If you've had a liver fluke infection or are recovering from one, your doctor may monitor your liver enzyme levels or order tests like:
-
ALT and AST (enzymes that show liver cell damage)
-
Bilirubin (high levels can indicate bile flow problems)
-
Ultrasound to check for bile duct blockages or scarring
For more information about checking your liver health at home, see At-Home Liver Tests: A Comprehensive Guide.
Can liver flukes come back after treatment?
If treatment is successful and you avoid re-infection, liver flukes should not return. However, if you continue eating raw or undercooked fish, especially in high-risk areas, you can get infected again.
Always follow food safety practices to reduce your risk.
What's the link between liver flukes and UTI symptoms?
Though liver flukes and UTIs affect different organs, some overlapping symptoms like abdominal pain or fatigue may confuse diagnosis.
If you're unsure, a urine test can help rule out urinary tract infections.
Related health areas to monitor
If you’ve had liver flukes, it’s important to monitor your overall metabolic and organ health. These areas are connected:
-
Kidney Health: Liver infections can indirectly affect kidney function.
-
Urinary Tract Health: To rule out concurrent infections.
-
Blood Sugar Health: Chronic infections may impact metabolism.
When to see a doctor
See a healthcare provider if you:
-
Have eaten raw freshwater fish recently
-
Feel persistent abdominal pain
-
Notice yellowing of your skin or eyes
-
Experience fatigue, itching, or digestive issues
These may be signs of liver or bile duct inflammation.
Final thoughts
Liver flukes are a preventable and treatable condition. While infections may not always cause symptoms right away, they can cause serious long-term damage if ignored.
If you've eaten raw or undercooked fish in high-risk areas, talk to your healthcare provider. Early treatment can stop the infection and protect your liver.
For peace of mind, consider using at-home liver tests to monitor your health between checkups.
References
Fletcher, J. (2017, September 21). Everything you need to know about liver fluke. Retrieved September 9, 2025, from Medicalnewstoday.com website: https://www.medicalnewstoday.com/articles/319479
Good, R., & Dmitriy Scherbak. (2023, May). Fascioliasis. Retrieved September 9, 2025, from Nih.gov website: https://www.ncbi.nlm.nih.gov/books/NBK537032/
Harrington, D., Lamberton, P. H. L., & McGregor, A. (2017). Human liver flukes. the Lancet. Gastroenterology & Hepatology, 2(9), 680–689. https://doi.org/10.1016/s2468-1253(17)30111-5
Lim, J. H. (2011). Liver Flukes: the Malady Neglected. Korean Journal of Radiology, 12(3), 269. https://doi.org/10.3348/kjr.2011.12.3.269
Liver Fluke: Fascioliasis, Causes, Symptoms & Treatments. (2024, July 24). Retrieved September 9, 2025, from Cleveland Clinic website: https://my.clevelandclinic.org/health/diseases/liver-fluke
Young, B. (2017, August 22). Liver Fluke. Retrieved September 9, 2025, from Healthline website: https://www.healthline.com/health/liver-fluke
