About Liver Flukes

Source: National Center for Emerging and Zoonotic Infectious Diseases (NCEZID) — Content from the Centers for Disease Control and Prevention (public domain).

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).