Hepatic capillariasis

Hepatic capillariasis
Other names: Capillaria hepatica hepatitis;[1] hepatic capillariasis infection[2][3]
Top:C hepatica life cycle[2] Bottom: Image features of liver infected with C. hepatica [4]
Specialty	Infectious disease
Symptoms	Fever , abdominal pain[4]
Causes	C. hepatica[4]
Diagnostic method	Liver tissue biopsy[4]
Differential diagnosis	Amoebic liver abscess,Visceral larva migrans [5]
Treatment	Antiparasitic medications[4]

Hepatic capillariasis is a parasitic infection caused by the nematode Capillaria hepatica. This parasite can occasionally infect humans leading to liver damage, as the adult worms lay eggs within the liver, this causes inflammation.^[2][6]

Humans get the infection by ingesting embryonated eggs via contaminated food, or water. Symptoms include fever, hepatomegaly, and eosinophilia Diagnosis is made through liver biopsy, and treatment involves antiparasitic medications and steroids.^[6]

Signs and symptoms

In terms of the presentation we find that the following is observed:^[2][6]

• Fever
• Jaundice
• Hepatomegaly

Complications

As to the complications we find that chronic inflammation and the deposition of eggs can lead to the formation of scar tissue in the liver, which can progress to cirrhosis, that impairs liver function. In severe cases liver failure can occur^[7][4]

Cause

Capillaria hepatica is a parasitic nematode which causes hepatic capillariasis in numerous mammal species, including humans.^[8]

The life cycle of C. hepatica may be completed in a single host species. However, the eggs, which are laid in the liver, most mature outside of the host body prior to infecting a new host.^[8]

• 
  Capillaria hepatica tissue
• 
  C. hepatica

Mechanism

Humans get infected by ingesting embryonated C. hepatica eggs, often via contaminated food, water. After ingestion, the embryonated eggs hatch in the small intestine, releasing larvae. These larvae then penetrate the intestinal wall and migrate via the portal vein to liver. Within the liver parenchyma, the larvae mature into adult worms over a period of one month^[6][2]

The immune system tries to partition the foreign parasitic material by forming granulomas; collections of immune cells, macrophages, eosinophils, lymphocytes, surround the eggs. There is a increase in eosinophils in the peripheral blood and within the liver tissue . The inflammatory process and the physical presence of eggs/worms lead to diffuse necrosis of liver cells. This in turn leads to chronic inflammation and deposition of collagen fibers, causing septal fibrosis and, maybe leading to liver cirrhosis^{[9][1][2][10][11]}

Diagnosis

As to the diagnosis of Hepatic capillariasis the epidemiological history, and clinical manifestations, are taken into account as well as:^[4]

• Ultrasound
• MRI
• Liver tissue biopsy

Differential diagnosis

As to the DDx in Hepatic capillariasis we find the following:^[5]

• Visceral larva migrans
• Amoebic liver abscess
• Strongyloides stercoralis

Treatment

In terms of treatment, hepatic capillariasis requires a combination of management strategies:^[2][12]

• Antiparasitic drug(albendazole or mebendazole)
• Corticosteroids
• Supportive care

Epidemiology

In terms of the geographic distribution of C. hepatica we find it is located worldwide in wildlife populations.Human cases have been reported from all continents except for Australia.^[13][2][6]

Human cases have been reported from North America, Central America, and South America(Brazil, Mexico, US), Asia(India, Japan, Korea, China), Europe(Italy, Germany, Czechoslovakia, England), and Africa (South Africa, Nigeria, Ivory Coast).The true incidence of human cases may be underestimated due to its diagnostic challenges.^[14][2]

History

Hepatic capillariasis was discovered by Dr Thomas Bancroft in 1893.^[15]

While the parasite itself was identified in 1893, the first documented case of human hepatic capillariasis was described by MacArthur in 1924^[16]

Research

Recent research is exploring the host immune response to Capillaria hepatica infection. Studies have investigated the role of PD-1/PD-L2 signaling and alternatively activated macrophages in determining the immune response and liver pathology, which could lead to new therapeutic targets to modulate the inflammatory response.^[17]

See also

• Capillariasis
• Intestinal capillariasis

Notes

1.^ Case report (PubMed indexed)

References

Further reading

• Pal, Mahendra; Gutama, Kirubel Paulos (1 January 2024). "Capillariasis as an Emerging Foodborne Helminthic Disease". Encyclopedia of Food Safety (Second ed.). Academic Press. pp. 556–563. ISBN 978-0-12-822520-2.
• Williams, Samuel (2001). Samuel, William M.; Pybus, Margo J.; Kocan, A. Alan (eds.). Parasitic diseases of wild mammals (2nd ed.). Ames: Iowa State University Press. doi:10.1002/9780470377000. ISBN 9780470377000. Archived from the original on 16 January 2024. Retrieved 4 June 2025.