An eight-centimetre (3-inch) parasitic worm was found live and wriggling after shocked surgeons extracted it from an Australian woman’s brain in June 2022.
The 64-year-old woman from New South Wales experienced three weeks of abdominal pain and diarrhea, followed by a dry cough and night sweats before she was admitted to her local hospital in January 2021.
She was diagnosed and treated for eosinophilic pneumonia, a disease where eosinophils, a variety of disease-fighting white blood cells, accumulate in the lungs.
Eosinophilic pneumonia is not well understood but is known to have both infectious and non-infectious causes. Infectious causes are “almost always due to parasitic infections,” according to the U.S. National Institutes of Health.
Three weeks later, the woman continued to experience fevers and dry coughs, with CT scans revealing lesions in her liver, lungs, and spleen. Due to her immunosuppression condition, she was given a few doses of ivermectin.
By 2022, she began experiencing forgetfulness and worsening depression. It was at this point that an MRI scan of her brain showed a lesion in her right frontal lobe.
In June, she underwent an open biopsy, and surgeons removed a “stringlike structure” which turned out to be a live Ophidascaris robertsi, a roundworm commonly found in carpet pythons.
Everyone involved in the surgery was “absolutely stunned,” Canberra Hospital infectious disease physician Dr. Sanjaya Senanayake said.
“This patient had been treated for what was a mystery illness. We thought ultimately it was an immunological condition because we hadn’t been able to find the parasite before,” Dr. Senanayake told the Australian Broadcasting Corporation.
“Then, out of nowhere, this big lump appeared in the frontal part of her brain. So when the surgeon went in, she was going to do a biopsy: Was it cancer, was it an abscess?
“Suddenly, with her forceps, she’s picking up this thing that’s wriggling. She will tell you that she and everyone in that operating theatre were absolutely stunned.”
Scientists believe this was a world-first case of human infection by any Ophidascaris species.
“Although visceral involvement is common in animal hosts, the invasion of the brain by Ophidascaris larvae had not been reported previously. The patient’s immunosuppression may have enabled the larvae to migrate into the central nervous system,” scientists remarked in the Emerging Infectious Disease Journal, published by the U.S. Centers for Disease Control and Prevention (CDC).
“The growth of the third-stage larva in the human host is notable, given that previous experimental studies have not demonstrated larval development in domesticated animals, such as sheep, dogs, and cats, and have shown more restricted larval growth in birds and nonnative mammals than in native mammals.”
How Did She Get It?
The woman lived near a lake that is known to have carpet pythons, where she foraged a type of Australian native edible plant known as warrigal greens. It is also known as New Zealand spinach.
Scientists believe she became infected after accidentally ingesting the parasite’s eggs, either directly from eating the vegetables or indirectly by contamination of her hands or kitchen equipment.
They also believe that the lesions found in her lungs and liver were the result of the same parasite larvae but note the splenic lesions were due to unrelated issues.
“So we think that’s what’s happened,” Dr. Senanayake said.
“It is important for a lot of people who forage out there, not just for warrigal greens, just wash your hands after you’ve done that.”
The woman is now mostly recovered and living in the community while doctors and researchers continue to monitor her condition.
While improved, her neuropsychiatric symptoms continue to persist.