Humans are incidental hosts of this roundworm, and may become infected through ingestion of larvae in raw or undercooked snails or other vectors, or from contaminated water and vegetables.

[5] The larvae are then transported via the blood to the central nervous system, where they are the most common cause of eosinophilic meningitis, a serious condition that can lead to death or permanent brain and nerve damage.

[7][8] First described by Chinese parasitologist Hsin-Tao Chen (1904–1977) in 1935, after examining Cantonese rat specimens,[1] the nematode Angiostrongylus cantonensis was identified in the cerebrospinal fluid of a patient with eosinophilic meningitis by Nomura and Lim in Taiwan in 1944.

Nematodes are roundworms characterized by a tough outer cuticle, unsegmented bodies, and a fully developed gastrointestinal tract.

Following World War II, A. cantonensis spread throughout Southeast Asia and Western Pacific Islands, including Australia, Melanesia, Micronesia, and Polynesia.

[11] In 1961, an epidemiological study of eosinophilic meningitis in humans was conducted by Rosen, Laigret, and Bories, who hypothesized that the parasite causing these infections was carried by fish.

Other sporadic occurrences of the parasite in its rat hosts have been reported in Cuba, Egypt, Louisiana, Madagascar, Nigeria, and Puerto Rico.

the parasite has been shown to be proliferating at an alarming rate due to modern food-consumption trends and global transportation of food products.

[21] Unwashed fruits and vegetables, especially romaine lettuce, can be contaminated with snail and slug mucus or can result in accidental ingestion of these intermediate and paratenic hosts.

[27] Paratenic hosts of A. cantonensis include the predatory land flatworm Platydemus manokwari and the amphibians, Bufo asiaticus, Rana catesbeiana, Polypedates leucomystax and Fejervarya limnocharis.

[31] In 2004, a captive yellow-tailed black cockatoo (Calyptorhynchus funereus) and two free-living tawny frogmouths (Podargus strigoides) suffering neurological symptoms were shown to have the parasite.

[36] In 2018, in Mallorca two North African hedgehogs with signs of acute neurological disease were found to have A. cantonensis in their brains, one of them with a gravid female.

[37] The Hawaiʻi Department of Health states that freshwater opihi can carry the parasite, as well as other aquatic organisms such as prawns, frogs, and water monitor lizards.

[39] The presence of parasitic worms burrowed in the neural tissue of the human central nervous system (CNS) causes complications.

Caution should be advised in using eosinophilic meningitis as the only criterion for diagnosing angiostrongylus infestation in someone with classic symptoms, as the disease evolves with the migration of the worms into the CNS.

Removing cerebrospinal fluid at regular 3- to 7-day intervals is the only proven method of significantly reducing intracranial pressure and can be used for symptomatic treatment of headaches.

[41] There is growing evidence of moderate quality that suggests corticosteroid therapy using prednisolone[47] or dexamethasone[48] has beneficial effect in treating the CNS symptoms related to A. cantonensis infections.

[49][50] Although early research did not show treatment with antihelminthic agents (parasite-killing drugs) such as thiobendazole or albendazole effective in improving the clinical course of the illness,[51][42] a number of recent[when?]

[48][47][52][53] Although the addition of antihelminthic agents for management of A. cantonensis infection has a theoretical risk of precipitating a neurologic crisis by releasing an overwhelming load of antigens through simultaneous death of the larvae,[46] no study has shown this to exist in the clinical setting.