Liver Fluke

Overview

Liver fluke infection is caused by tiny flatworms called liver flukes. These parasites can get into your body when you eat raw or undercooked freshwater fish, crabs, crayfish, or freshwater plants, or when you drink contaminated water. The flukes travel to the liver and bile ducts, which are small tubes that carry bile from the liver. Liver fluke infection is not spread from person to person.

Liver fluke infection is not common in many parts of the world, but it is more common in some regions where people regularly eat raw freshwater fish or freshwater plants, or where sanitation and water safety are poor. The number of cases depends a lot on where you live or travel.

Anyone who eats raw or undercooked freshwater fish, crabs, crayfish, or freshwater plants, or who drinks contaminated water, can get liver fluke infection. People living in or traveling to areas where liver flukes are common are at higher risk. Children and older adults can get it too.

Symptoms

Common symptoms

• Many people have no symptoms at all.
• Mild indigestion or upset stomach.
• Pain in the upper right part of the belly.
• Feeling sick or being sick.
• Loose stools or diarrhea.
• Tiredness or feeling weak.
• Fever, especially in early infection.
• Yellowing of the skin or eyes in some cases.

Symptoms in children

• Children often have the same symptoms as adults, or no symptoms.
• Belly pain and poor appetite can happen.
• Long-term infection may affect growth and energy, so check with a doctor if you are worried.
• Children should be checked by a doctor if they have eaten raw freshwater fish or plants in a high-risk area.

Symptoms in older adults

• Older adults may have the same symptoms but can become dehydrated or more unwell more quickly.
• If you already have liver problems, symptoms may be more serious.
• Yellow skin or eyes, confusion, or severe belly pain needs urgent medical care.

Causes

Main causes

• Eating raw or undercooked freshwater fish that carry liver fluke larvae.
• Eating raw or undercooked freshwater crabs or crayfish.
• Eating raw freshwater plants, such as watercress, that carry the parasite.
• Drinking water contaminated with liver fluke larvae.
• Using contaminated water to wash food or utensils.

Risk factors

• Living in or traveling to areas where liver flukes are common.
• Regularly eating raw freshwater fish or freshwater plants.
• Drinking unsafe water or using it to prepare food.
• Poor sanitation in the area where food or water comes from.
• Working with freshwater fish, farming, or fishing in high-risk areas.

When to see a doctor

See a doctor urgently if:

• You have yellow skin or eyes.
• You have fever with belly pain.
• You have dark urine or pale stools.
• You have severe or worsening belly pain.
• You have signs of dehydration.
• You have vomiting blood or black stools.

Book a routine appointment if:

• You have eaten raw freshwater fish or freshwater plants in an area where liver fluke is common, even if you feel fine.
• You have mild stomach upset, tiredness, or poor appetite that does not go away.
• You have been told that a liver fluke infection may be going around in your area or among people you traveled with.
• You have a liver or bile duct problem and want to check whether a parasite could be involved.

Diagnosis

A doctor will ask about your symptoms, where you have lived or traveled, and what foods and water you have had. They will examine you and may order tests. Liver fluke infection is often found by checking stool samples for parasite eggs, but sometimes blood tests or scans are needed.

Tests that may be done

• Stool test to look for liver fluke eggs.
• Blood tests to check for signs of infection or liver irritation.
• Blood tests that look for the body's immune response to the parasite.
• Ultrasound scan of the liver and bile ducts.
• CT or MRI scan if more detail is needed.
• Sometimes a procedure to look inside the bile ducts if there is a blockage.

What to expect at your appointment

You may need to give a stool sample at home or at the clinic. Test results can take days to weeks. If the first tests are not clear, your doctor may repeat them or ask for other tests. Follow-up is important to make sure treatment has worked.

Treatment

Liver fluke infection is usually treated with prescription medicine that kills the parasite. The exact plan depends on the type of fluke, how severe the infection is, and your overall health. Some people also need tests or hospital care if the bile ducts are blocked or infected.

Self-care at home

• Take any prescribed medicine exactly as your doctor tells you.
• Rest when you feel tired and drink safe fluids.
• Eat balanced meals and avoid alcohol if your liver is irritated.
• Wash your hands well after using the toilet and before preparing food.
• Keep follow-up appointments and repeat tests if your doctor asks.
• Do not use leftover medicines or medicines bought online without medical advice.

Medical treatments

Treatment usually involves prescription antiparasitic medicine that kills the fluke. Your doctor will choose the right medicine and check whether you need a repeat course. You may need follow-up stool tests to confirm the infection has cleared. If you have a bile duct blockage or infection, you may need hospital care, fluids, and a procedure to drain or open the bile duct. Your doctor will explain the options that are right for you.

When is surgery considered?

Surgery is not common for liver fluke infection. It may be needed if there is a serious bile duct blockage, damage, or another complication that cannot be treated with medicine or a less invasive procedure. Your medical team will discuss this with you if it applies.

Living with this condition

Most people can carry on with normal daily life while being treated. Take your medicine as prescribed, rest when needed, and go to follow-up appointments. If you feel very tired, pace yourself and ask for help with daily tasks.

Lifestyle tips

• Cook freshwater fish, crabs, and crayfish thoroughly.
• Avoid raw freshwater plants such as watercress in high-risk areas.
• Drink safe water and use safe water to wash food and utensils.
• Wash your hands regularly.
• Avoid alcohol if your doctor says your liver is irritated.
• Tell your doctor about any new symptoms or if you feel worse.

Diet and exercise

Eat a balanced diet with safe, well-cooked food. Drink safe water. Gentle exercise, such as walking, can help you feel better if you are able. If you feel very tired or have liver problems, ask your doctor what activity level is safe for you.

Mental health and emotional wellbeing

It is normal to feel worried or anxious when you learn you have a parasite infection. Most people recover well, and talking about your concerns can help. If worry affects your sleep, mood, or daily life, tell your doctor or nurse. If you or someone else is in crisis, contact your local emergency services or a local crisis support line right away.

Prevention

Yes. You can lower your risk by cooking freshwater fish, crabs, and crayfish well, avoiding raw freshwater plants in high-risk areas, drinking safe water, and washing your hands and food carefully. Public health measures that improve sanitation and food safety also help prevent infection.

Vaccines

There is no vaccine for liver fluke infection.

Screening programmes

Screening is not usually offered to everyone. In areas where liver fluke is common, public health programs may use stool tests to find and treat infections in people at higher risk. If you have traveled or lived in a high-risk area and are worried, ask your doctor whether testing is needed.

Complications

If left untreated

• Long-term inflammation of the bile ducts.
• Blockage of the bile ducts.
• Gallstones or bile duct stones.
• Bile duct infection.
• Anaemia and poor nutrition.
• Rarely, long-term infection can raise the risk of bile duct cancer, but this is uncommon and treatment lowers the risk.

Long-term outlook

Most people recover well when liver fluke infection is found and treated. Treatment can clear the parasite and help prevent further liver or bile duct damage. Follow-up care is important, and early treatment gives the best chance of a full recovery.

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