The mysterious cause of a young Australian man's meningitis was finally found to be a dinner of raw slugs.
The student ate slugs for a dare
He had eaten two slugs for a dare five weeks before falling ill.
But slugs harbour Angiostrongylus cantonensis - also known as the rat lungworm - which can cause the potentially fatal brain inflammation.
Experts writing in the Medical Journal of Australia say that if people do want to eat slugs, they should cook them first, in order to kill the parasite.
The young man was admitted to hospital after experiencing headaches, nausea, vomiting, neck stiffness and sensitivity to light.
A series of tests were carried out by doctors, but the cause of his illness could not be determined, and he was discharged after 12 days.
However, his symptoms worsened, and five days later he was readmitted to another hospital with drowsiness, sight problems and a lack of sensation in his hands.
Brain scans showed he had developed lesions in his brain.
It was then that he admitted to eating two slugs from a Sydney garden some weeks earlier.
In eating the raw slugs, he had contracted the parasite Angiostrongylus cantonensis.
Humans usually ingest it when they eat raw or undercooked molluscs or crustaceans, or contaminated vegetables or salad.
The man was then given treatment to reduce intracranial pressure.
He improved gradually, and was discharged from hospital after 17 days.
But it was five months before he was able to return to full-time studies and competitive sports.
Writing in the journal, a team from the University of Sydney's Centre for Infectious Diseases and Microbiology led by Dr John Walker, said: "Angiostrongylus meningitis is usually mild and resolves spontaneously over six weeks.
He said A. cantonensis should be considered as a cause of aseptic meningitis in patients with similar symptoms "and a history of exposure to undercooked molluscs or crustaceans."