Clinical Features:
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.  Hepatic capillariasis (C. hepatica) manifests as an acute or subacute hepatitis with eosinophilia, with possible dissemination to other organs.  It may be fatal.  Pulmonary capillariasis (C. aerophila) may present with fever, cough, asthma, and pneumonia, and also may be fatal.

Laboratory Diagnosis:
The specific diagnosis of C. philippinensis is established by finding eggs, larvae and/or adult worms in the stool, or in intestinal biopsies.  Unembryonated eggs are the typical stage found in the feces.  In severe infections, embryonated eggs, larvae, and even adult worms can be found in the feces.
The specific diagnosis of C. hepatica infection is based on demonstrating the adult worms and/or eggs in liver tissue at biopsy or necropsy.  (Note: identification of C. hepatica eggs in the stool is a spurious finding, which does not result from infection of the human host, but from ingestion by that host of livers from infected animals.)
The specific diagnosis of C. aerophila is based on demonstrating eggs in stool or in lung biopsy.

Diagnostic findings

• Microscopy
• Morphologic comparison with other intestinal parasites

Treatment:
The drug of choice is mebendazole*, and albendazole* is an alternative.  For additional information, see the recommendations in The Medical Letter (Drugs for Parasitic Infections).

* This drug is approved by the FDA, but considered investigational for this purpose.