[1] Infection with Angiostrongylus cantonensis (rat lungworm) can occur after ingestion of raw or undercooked snails or slugs, and less likely unwashed fruits and vegetables.

[citation needed] Central Nervous System (CNS) signs and symptoms begin with mild cognitive impairment and slowed reactions, and in a very severe form often progress to unconsciousness.

[6][7] Certain animal species such as freshwater prawns, crayfish, crabs, centipedes, lizards and frogs and toads may act as paratenic hosts for the nematode larvae and cause accidental transmission when consumed raw or undercooked.

[3] A. cantonensis is a nematode roundworm with 3 outer protective collagen layers and a simple stomal opening or mouth with no lips or buccal cavity leading to a fully developed gastrointestinal tract.

Sometimes the larvae will develop into the adult form in the brain and cerebrospinal fluid (CSF), but they quickly die, inciting the inflammatory reaction that causes symptoms of infection.

[3] Diagnosis of Angiostrongyliasis is complicated due to the difficulty of presenting the angiostrongylus larvae themselves, and will usually be made based on the presence of eosinophilic meningitis and history of exposure to snail hosts.

[5] Occasionally worms found in the cerebrospinal fluid or surgically removed from the eye can be identified to diagnose Angiostrongyliasis.

In cases of eosinophilic meningitis, it will rarely produce worms even when they are present in the CSF, because they tend to cling to the end of nerves.

[citation needed] In patients with elevated eosinophils, serology can be used to confirm a diagnosis of angiostrongyliasis rather than infection with another parasite.

Education to prevent the introduction of rats or snail vectors outside endemic areas is important to limit the spread of the disease.

[citation needed] To avoid infection when in endemic areas, travelers should:[citation needed] Treatment of angiostrongyliasis is not well defined, but most strategies include a combination of anti-parasitics to kill the worms, steroids to limit inflammation as the worms die, and pain medication to manage the symptoms of meningitis.

[4] Anthelmintics should generally be paired with corticosteroids in severe infections to limit the inflammatory reaction to the dying parasites.

Studies suggest that a two-week regimen of a combination of mebendazole and prednisolone significantly shortened the course of the disease and length of associated headaches without observed harmful side effects.

[12] Symptomatic treatment is indicated for symptoms such as nausea, vomiting, headache, and in some cases, chronic pain due to nerve damage or muscle atrophy.

[13] The giant African land snail, which can be a vector of the parasite, has been introduced to Brazil as an invasive species and is spreading the disease.