Fasciola hepatica

Definition

Fasciola hepatica, also known as the sheep liver fluke or common liver fluke, is a parasitic helminth that primarily infects the liver of various mammals, including humans. As a member of the Phylum Platyhelminthes, this trematode parasite is a significant concern in the context of Parasitic Helminths.

5 Must Know Facts For Your Next Test

1. Fasciola hepatica has a complex life cycle, involving both an intermediate snail host and a definitive mammalian host, such as sheep, cattle, or humans.
2. Humans can become infected by ingesting contaminated water or vegetables containing the parasite's infective larval stage, known as metacercariae.
3. The adult Fasciola hepatica flukes reside in the bile ducts of the infected host's liver, where they feed on blood and bile, causing significant tissue damage.
4. Fascioliasis, the disease caused by Fasciola hepatica, can lead to symptoms such as abdominal pain, fever, nausea, and in severe cases, liver cirrhosis or failure.
5. Diagnosis of Fasciola hepatica infection typically involves serological tests or the identification of the parasite's eggs in the host's feces.

Review Questions

• Describe the life cycle of Fasciola hepatica and explain how it can infect humans.
  • The life cycle of Fasciola hepatica involves an intermediate snail host and a definitive mammalian host, such as humans. The adult flukes residing in the bile ducts of the mammalian host release eggs that are passed through the feces. These eggs hatch in freshwater, releasing larvae that infect a specific type of freshwater snail. Inside the snail, the larvae undergo further development and eventually emerge as cercariae, which can then encyst on aquatic plants as metacercariae. Humans become infected by ingesting these metacercariae, typically through contaminated water or vegetables. Once inside the human host, the metacercariae excyst, penetrate the intestinal wall, and migrate to the liver, where they mature into adult flukes and begin the cycle anew.
• Explain the pathogenesis of Fasciola hepatica infection and the potential complications it can cause in humans.
  • Fasciola hepatica infection, known as fascioliasis, can lead to significant health complications in humans. After the metacercariae are ingested and excyst in the intestine, the immature flukes migrate through the intestinal wall and peritoneal cavity, eventually reaching the liver. In the liver, the flukes burrow through the parenchyma, causing extensive tissue damage and inflammation. As the adult flukes mature and establish themselves in the bile ducts, they can obstruct bile flow, leading to biliary colic, cholangitis, and potentially liver cirrhosis or failure in severe cases. The migratory phase of the infection can also cause ectopic infections in other organs, such as the lungs or brain, further complicating the disease. Proper diagnosis and timely treatment are crucial to manage the complications associated with Fasciola hepatica infection.
• Discuss the epidemiological and public health significance of Fasciola hepatica, and evaluate the measures that can be taken to prevent and control this parasitic infection.
  • Fasciola hepatica is a significant public health concern, particularly in regions where livestock farming and the consumption of contaminated water or vegetables are common. As a zoonotic parasite, Fasciola hepatica can be transmitted from infected animals, such as sheep and cattle, to humans, making it an important consideration in the context of One Health. The disease burden associated with fascioliasis is substantial, with millions of people estimated to be infected worldwide. To prevent and control Fasciola hepatica infections, a multifaceted approach is necessary. This includes improving sanitation and access to clean water, educating the public on proper food preparation and hygiene practices, implementing effective snail control measures in endemic areas, and providing timely diagnosis and treatment for infected individuals. Collaboration between public health authorities, veterinary professionals, and the community is crucial to effectively mitigate the impact of this parasitic helminth and safeguard public health.

Related terms

Trematoda: The class of parasitic flatworms, also known as flukes, to which Fasciola hepatica belongs.

Zoonosis: A disease that can be transmitted from animals to humans, such as the infection caused by Fasciola hepatica.

Intermediate Host: An organism, such as a freshwater snail, that harbors a parasite's larval stage before the parasite infects its definitive host, like a mammal.