Angiostrongyliasis, neural

Angiostrongylus infection


Adult worms of A. cantonensis reside in the pulmonary arteries and right ventricle within the normal definitive host. Females lay eggs that hatch in the smallest branches of the pulmonary arteries, giving rise to first-stage larvae. These larvae travel to the throat, are swallowed, and then expelled in feces. They either penetrate or are consumed by a gastropod intermediate host. Following two molts, third-stage larvae, which are infectious to mammals, emerge.

Upon ingestion of the infected gastropod by the definitive host, the third-stage larvae move to the brain, where they mature into young adults. These young adults return to the venous system and eventually reach the pulmonary arteries, becoming sexually mature. It's important to note that various animals serve as paratenic (transport) hosts: they ingest infected snails and carry third-stage larvae, which can resume development upon being consumed by a definitive host.

Humans can contract the infection by consuming raw or undercooked snails or slugs carrying the parasite. Ingestion of raw produce containing a small snail or slug, or parts of these, may also lead to infection. There's uncertainty regarding whether larvae can exit infected gastropods in slime, which might be infectious to humans if ingested, for instance, via produce. Infection can also occur through ingestion of invertebrate paratenic hosts containing L3 larvae (e.g., crabs, freshwater shrimp).

Within humans, larvae migrate to the brain, rarely to the lungs, where they eventually die. Although larvae may progress to fourth or fifth stages in the human host, they seem incapable of reaching full maturity.


  • Southeast Asia and Pacific Islands
  • Has been reported from Africa, the Caribbean, Australia, Hawaii and the southern United States.

Clinical Findings

  • Eosinophilic meningitis
  • Somatic symptoms (e.g. headache, fever, malaise)
  • Varying degrees of neurological dysfunction

Ocular angiostrongyliasis

  • Uveitis
  • Blurred vision
  • Substantial loss of visual acuity


Clinical and Morphological Diagnosis:

In cases of eosinophilic meningitis caused by A. cantonensis, the cerebrospinal fluid (CSF) displays abnormalities such as increased pressure, elevated protein levels, and a heightened presence of leukocytes, often with eosinophilia. Although rare, larvae have occasionally been identified either in the CSF or within sections of brain tissue.

Serological Diagnosis:

Method: Western Blot

Note: Neuroangiostrongyliasis leads to eosinophilic meningitis. Specific antibodies can also be detected in the cerebrospinal fluid (CSF). CSF may often show hyperleukocytosis with >10% eosinophilic granulocytes.

Prevention and control

  1. Thoroughly Cook Food: Ensure that snails, slugs, or any food items containing these gastropods are cooked thoroughly before consumption. Avoid consuming raw or undercooked snails or slugs.

  2. Wash Produce: Carefully wash fruits and vegetables, particularly those that might harbor small snails or slugs, to remove any potential contaminants before eating raw produce.

  3. Practice Good Hygiene: Maintain proper hygiene practices, especially after handling snails, slugs, or working in areas where they are found. Wash hands thoroughly with soap and water.

  4. Be Cautious with Invertebrates: Exercise caution when consuming invertebrates like crabs or freshwater shrimp, as they might contain L3 larvae. Ensure they are properly cooked before consumption.

  5. Awareness of Slime Contamination: Be aware of the potential risk posed by slime trails from infected gastropods. There is uncertainty regarding whether larvae can exit infected gastropods in slime, which might be infectious if ingested, particularly on produce. Cleaning and washing produce thoroughly may help minimize this risk.