Key points
- Liver flukes are parasites that can infect humans and cause liver and bile duct disease.
- There are two families of liver flukes that cause disease in humans: Opisthorchiidae (which includes species of Clonorchis and Opisthorchis) and Fasciolidae (which includes species of Fasciola).
- These two families of liver flukes differ in their geographic distribution, life cycle, and long-term outcome after clinical infection.
Liver Flukes
Clonorchiasis (Clonorchis Infection)
Clonorchis is a liver fluke (type of parasitic worm) that can infect the liver, gallbladder, and bile duct.
- Clonorchis (also known as Chinese liver fluke disease), is part of the Opisthorchiidae family of liver flukes.
- You cannot get Clonorchis from another person, and you cannot get it from consuming untreated drinking water.
- Clonorchis infections can last for several years (the lifespan of the parasite).
Fasciola (Fascioliasis Infection)
Fasciola is a liver fluke that can infect the liver and bile duct of exposed people and animals, such as sheep, cattle, goats, and other plant-eating domestic and wild animals.
- Fasciola parasites can cause an infectious disease called fascioliasis. Generally, fascioliasis is more common in people who live or work around livestock (e.g., sheep, cattle, goats) in areas where animal infections are common.
Two Fasciola species can infect people:
- Fasciola hepatica: the main species that infects people. Other names are "the common liver fluke" and "the sheep liver fluke."
- Fasciola gigantica: a related species that primarily affects domestic and wild animals but can also infect people.
Fascioliasis occurs in all continents except Antarctica, in over 70 countries, especially where there are sheep, cattle, or goats.
- In most cases, people can get Fasciola infection by eating raw watercress or other freshwater plants contaminated by larvae.
- People can get infected by consuming contaminated water that they drink. People can also get infected by eating vegetables that they washed or irrigated with contaminated water.
- People cannot get Fasciola from another person.
Opisthorchis (Opisthorchis Infection)
Opisthorchis is a liver fluke (type of parasitic worm) that can infect the liver, gallbladder, and bile duct.
- Opisthorchis is part of the Opisthorchiidae family of liver flukes.
- There is Opisthorchis viverrini (i.e., the Southeast Asian liver fluke) and O. felineus (i.e., the cat liver fluke).
- You cannot get Opisthorchis from another person, and you cannot get it from consuming untreated drinking water.
- Opisthorchis infections can last for several years (the lifespan of the parasite).