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DPDx is an education resource designed for health professionals and laboratory scientists. For an overview including prevention and control visit www.cdc.gov/parasites/angiostrongyliasis.

Angiostrongyliasis

[Angiostrongylus cantonensis] [Angiostrongylus costaricensis]

Angiostrongylus costaricensis female worm in appendix tissue sections stained with hematoxylin and eosin. Notice the thick, multinucleate intestine (IN) and eggs (EG) within the uterus (UT).

Angiostrongylus costaricensis female worm in appendix tissue sections stained with hematoxylin and eosin. Notice the thick, multinucleate intestine (IN) and eggs (EG) within the uterus (UT).


Angiostrongylus cantonensis third stage (L3), infective larva recovered from a slug. Image captured under differential interference contrast (DIC) microscopy.

Angiostrongylus cantonensis third stage (L3), infective larva recovered from a slug. Image captured under differential interference contrast (DIC) microscopy.


Causal Agents

The nematode (roundworm) Angiostrongylus cantonensis, the rat lungworm, is the most common cause of human eosinophilic meningitis. In addition, Angiostrongylus (Parastrongylus) costaricensis is the causal agent of abdominal, or intestinal, angiostrongyliasis.


Life Cycle

Life cycle of angiostrongyliasis

Adult worms of A. cantonensis live in the pulmonary arteries of rats. The females lay eggs that hatch, yielding first-stage larvae, in the terminal branches of the pulmonary arteries. The first-stage larvae migrate to the pharynx, are swallowed, and passed in the feces. They penetrate, or are ingested by, an intermediate host (snail or slug). After two molts, third-stage larvae are produced, which are infective to mammalian hosts. When the mollusk is ingested by the definitive host, the third-stage larvae migrate to the brain where they develop into young adults. The young adults return to the venous system and then the pulmonary arteries where they become sexually mature. Of note, various animals act as paratenic (transport) hosts: after ingesting the infected snails, they carry the third-stage larvae which can resume their development when the paratenic host is ingested by a definitive host. Humans can acquire the infection by eating raw or undercooked snails or slugs infected with the parasite; they may also acquire the infection by eating raw produce that contains a small snail or slug, or part of one. There is some question whether or not larvae can exit the infected mollusks in slime (which may be infective to humans if ingested, for example, on produce). The disease can also be acquired by ingestion of contaminated or infected paratenic animals (crabs, freshwater shrimps). In humans, juvenile worms migrate to the brain, or rarely in the lungs, where the worms ultimately die. The life cycle of Angiostrongylus (Parastrongylus) costaricensis is similar, except that the adult worms reside in the arterioles of the ileocecal area of the definitive host. In humans, A. costaricensis often reaches sexual maturity and release eggs into the intestinal tissues. The eggs and larvae degenerate and cause intense local inflammatory reactions and do not appear to be shed in the stool.

Geographic Distribution

Most cases of eosinophilic meningitis have been reported from Southeast Asia and the Pacific Basin, although the infection is spreading to many other areas of the world, including Africa and the Caribbean. Abdominal angiostrongyliasis has been reported from Costa Rica, and occurs most commonly in young children.

Clinical Presentation

Clinical symptoms of eosinophilic meningitis are caused by the presence of larvae in the brain and by local host reactions. Symptoms include severe headaches, nausea, vomiting, neck stiffness, seizures, and neurologic abnormalities. Occasionally, ocular invasion occurs. Eosinophilia is present in most of cases. Most patients recover fully. Abdominal angiostrongyliasis mimics appendicitis, with eosinophilia.

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  • Page last reviewed November 29, 2013
  • Page last updated November 29, 2013
  • Content source: Global Health - Division of Parasitic Diseases and Malaria
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