Skip directly to search Skip directly to A to Z list Skip directly to site content
CDC Home
For questions about DPDx, contact us

DPDx is an education resource designed for health professionals and laboratory scientists. For an overview including prevention and control visit

Intestinal Capillariasis

[Capillaria philippinensis]

Eggs of C. philippinensis in unstained wet mounts of stool.

Egg of C. philippinensis in an unstained wet mount of stool.

Causal Agent

The nematode (roundworm) Capillaria philippinensis causes human intestinal capillariasis. 

Life Cycle

Life cycle of Capillaria philippinensis.

Typically,unembryonated eggs are passed in the human stool The number 1 and become embryonated in the external environment The number 2; after ingestion by freshwater fish, larvae hatch, penetrate theintestine, and migrate to the tissues The number 3. Ingestion of raw or undercooked fish results in infection of thehuman host. Humans are the only demonstrated hosts The number 4. The adults of Capillaria philippinensis (males: 2.3 to 3.2mm; females: 2.5 to 4.3 mm) reside in the human small intestine, where theyburrow in the mucosa The number 5. The females deposit unembryonated eggs. Some of thesebecome embryonated in the intestine, and release larvae that can causeautoinfection. This leads to hyperinfection (a massive number of adult worms) The number 6. Capillaria philippinesis is currently considered aparasite of fish eating birds, which seem to be the natural definitive host The number 7.

Geographic Distribution

Capillaria philippinensis is endemic in the Philippines and also occurs in Thailand. Rare cases have been reported from other Asian countries, the Middle East, and Colombia.

Clinical Presentation

Intestinal capillariasis (caused by C. philippinensis) manifests as abdominal pain and diarrhea, which, if untreated, may become severe because of autoinfection. A protein-losing enteropathy can develop which may result in cachexia and death.

Back to Top

For questions about DPDx, contact us
  • Page last reviewed November 29, 2013
  • Page last updated November 29, 2013
  • Content source: Global Health - Division of Parasitic Diseases and Malaria
  • Notice: Linking to a non-federal site does not constitute an endorsement by HHS, CDC or any of its employees of the sponsors or the information and products presented on the site. The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Road Atlanta, GA 30329-4027, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO