Angiostrongyliasis is infection with larvae of worms of the genus Angiostrongylus; intestinal symptoms or eosinophilic meningitis occurs depending on the infecting species.
Angiostrongylus are parasites of rats. Excreted larvae are taken up by intermediate hosts (snails and slugs) and transport hosts (certain crabs and freshwater shrimp). Human infection is acquired by ingestion of raw or undercooked snails or slugs or transport hosts; it is unclear whether larval contamination of vegetables (eg, in slime from snails or slugs that crawl on the food) can cause infection.
A. cantonensis infection occurs predominantly in Southeast Asia and the Pacific Basin, although infection has been reported elsewhere. The larvae migrate from the GI tract to the meninges, where they cause eosinophilic meningitis, with fever, headache, and meningismus. Occasionally, ocular invasion occurs.
A. costaricensis infection occurs in the Americas. Adult worms reside in arterioles of the ileocecal area, and eggs can be released into the intestinal tissues, resulting in local inflammation with abdominal pain, vomiting, and fever. Abdominal angiostrongyliasis mimics appendicitis; a painful right lower quadrant mass may develop.
Diagnosis is suspected based on a history of ingesting potentially contaminated material. Patients with meningeal findings require lumbar puncture; CSF shows eosinophilia, but parasites are rarely visible. Diagnosis of GI infection is difficult because larvae and eggs are not present in stool; however, if surgery is done (eg, for suspected appendicitis), eggs and larvae can be identified in tissues removed during surgery.
A. cantonensis meningitis is treated with analgesics, corticosteroids, and removal of CSF at frequent intervals to reduce CNS pressure. Most patients have a self-limited course and recover completely.
Treatment of A. costaricensis infection is controversial. Anthelmintics do not appear to be effective and may be harmful because of the inflammatory response provoked by antigen released from dead parasites.
Last full review/revision December 2009 by Richard D. Pearson, MD
Content last modified February 2012