Ingestion of common garden slugs or snails can cause meningitis, a report in the current issue of the Medical Journal of Australia has found. These molluscs are hosts of the larval stage of a lung worm parasite of rats. The parasite has been found in several other mammal species in Sydney, but this is the only record of a locally acquired human infection.

The report, co-authored by Dr John Walker, from the Department of Medicine at Sydney University, examines the clinical record of a young man who exhibited puzzling symptoms over a period of weeks before being diagnosed with human eosinophilic meningitis.

"Repeated questioning revealed that the patient had ingested, 5 weeks earlier, for a dare, two slugs from a garden in a Sydney suburb," Dr Walker said.

Treatment included repeated cerebrospinal fluid drainage and regular administration of corticosteroids. The patient was finally discharged from hospital 17 days after diagnosis. He continued taking medication for four weeks after discharge.

"After 5 months, he successfully returned to full-time studies and competitive sport," Dr Walker said.

Angiostrongylus cantonensis is the most common infectious cause of eosinophilic meningitis worldwide and is endemic in South-East Asia and the Pacific Basin.

The first human infection with the A. cantonensis parasite reported in Australia was from Brisbane in 1971. Since then a fatal case occurred in a child who ingested molluscs in a suburban Brisbane garden.

Humans become accidental hosts when they ingest the laval stage in raw or undercooked molluscs or crustaceans or in fresh vegetables contaminated by infected molluscs," Dr Walker said.

"In our patient, the acute febrile gastrointestinal illness six days after consuming the slugs may have been caused by invasion of the parasite through the intestinal wall.

"Initial entry into the meninges, and subsequent migration through brain parenchyma, caused the clinical picture of meningitis followed by encephalitis.

"Angiostrongylus meningitis is usually mild and resolves spontaneously over six weeks," Dr Walker said.

The Medical Journal of Australia is a publication of the Australian Medical Association.

CONTACT:     Dr John Walker, 02 9816 2815 (H) 02 9845 7663 (W)

                    Judith Tokley, AMA, 0408 824 306