Worms and other parasitesCan affect people
Liver fluke disease
Also called Fasciolosis, liver rot
Flukes in the liver cause anaemia, poor growth and swelling under the jaw. In sheep it can kill suddenly, and in cattle and buffalo it is usually a slow, chronic loss of condition and milk.
Cause and spread
- Cause
- The liver flukes Fasciola hepatica and, in warmer regions such as Asia and Africa, Fasciola gigantica.
- How it spreads
- Animals swallow fluke cysts on wet grass and water plants. The parasite passes through freshwater snails, so wet, swampy pasture is where infection happens.
- People
- Fasciola has a wide host range that includes people. Ask your doctor or veterinarian about precautions where it is common.
Signs to watch for
- Anaemia, pale gums and weakness
- Swelling under the jaw (bottle jaw)
- Poor weight gain and lower milk yield
- Sudden death or a swollen, painful abdomen in sheep
- Chronic loss of condition in cattle and buffalo
Many diseases look alike. Only a laboratory test can tell them apart, so please see a veterinarian for any sick animal.
How it is diagnosed
Fluke eggs are found in dung by sedimentation, but only once the flukes are laying eggs, and results can vary from day to day, so repeat tests may be needed. Antibody tests are available in some countries.
Prevention and control
- Treat infected animals and check that treatment worked
- Keep animals off wet, snail-infested pasture where possible; drain or fence wet areas
- Use deworming at the right times for your area, as advised by your veterinarian
- Be aware that drug resistance can occur
Where this information comes from
- Fasciola hepatica in Ruminants · Merck Veterinary Manual
- Fasciola gigantica in Ruminants · Merck Veterinary Manual
General information for animal owners and veterinarians, last checked October 2026. It does not replace the advice of your veterinarian, who should decide which tests and treatment your animal needs.