Doctors finally identified the cause of a mystery illness in an Australian woman: A worm living in her brain! This first-ever case—where this worm jumped from a python to a human—raises new concerns about rare illnesses caused by humans encroaching on wildlife habitats.
Researched by: Rachel John
She had a live worm in her brain? Explain!
How it started: Back in 2021, a 64-year-old woman was admitted to a local hospital in New South Wales. She had been complaining of abdominal pain, a dry cough and night sweats. Doctors discovered lesions on her lungs, liver and spleen—and a high white blood cell (WBC) count, which indicated her body was fighting some kind of infection. But they couldn’t detect a cause for her symptoms. The initial diagnosis: pneumonia linked to the build-up of eosinophils, a type of white blood cell. They gave her steroids—which seemed to help—and discharged her.
Diagnosis #2: In a month, she was hospitalised again with fever and cough—and the WBC counts remained high. This time, the doctors decided that the culprit was a blood disorder—and gave her meds that suppressed her immune system.
The horrific discovery: The woman seemed to improve for a couple of months. But in early 2022, she started experiencing cognitive and memory problems—along with depression. That’s when doctors did an MRI scan and discovered an “atypical lesion” on the right frontal lobe of the brain. So they decided to perform a surgery to biopsy the lesion. Then this happened:
That was when Hari Priya Bandi, the neurosurgeon who operated on the woman, spotted the worm. It looked out of place within the lesion, red but too pale to be a blood vessel. She grasped it with her surgical instruments. “She did, until it started moving,” [her colleague Mehrab] Hossain recounted.
The worm: was red, three inches long and alive! It was sent to a lab where it was identified as Ophidascaris robertsi—a type of roundworm that is native to Australia. It had been living in her brain for two months! If you need a visual:
The treatment: The patient was given an intensive deworming medication to flush any other larvae living in her body. And she has recovered—though not fully:
Six months after her surgery and three months after being tapered off steroids, her eosinophil levels had returned to normal. Unfortunately, the woman’s neuropsychiatric symptoms had improved but not completely recovered by that time.
The world learned of the case when the doctors published a paper recently.
A worm in the brain?! How the eff does that happen?
To be clear, this is the first case of this type of roundworm infecting a human. And it is certainly the first case where a worm has been found in a person’s brain:
The invasion of the brain by Ophidascaris larvae had not been reported previously… 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.
Also this: “Previously, this parasite has been found in juvenile form in the organs of koalas and sugar gliders, but never before in a mammal's brain as a fully-fledged adult.” Its discovery is truly astonishing. And that’s why the case is making headlines around the world.
The path of infection: Carpet pythons usually carry this type of roundworm—and spread it to other animal species:
What normally happens is that carpet pythons in Australia carry the Ophidascaris robertsi and shed parasite eggs in their feces, spreading through vegetation that small mammals and marsupials eat. At some point, pythons also eat those same infected animals, and the parasite then lives inside the snake, completing the cycle.
The woman lived near a habitat for carpet pythons—and foraged for wild greens—which were likely infected with the roundworm eggs. She could have consumed the larvae by eating the greens—or from contaminated hands or kitchen surfaces.
Btw, this is what a carpet python looks like:
The stomach-churning spread: What’s truly horrific about this story is how the worm then spread through her body:
[A]ny roundworm eggs would have followed their usual playbook, releasing larva to burrow into their host’s stomach wall, [professor of parasitology Jan] Šlapeta said. The larva usually stay in a cavity near the stomach, but Šlapeta said the roundworm found inside the woman may have burrowed to other organs in confusion, which would explain the lesions in her liver.
The irony is that the steroids prescribed to suppress her immune system—due to the high WBC count—may have helped the worm to survive inside her body. The doctors couldn’t spot the worm because the eggs were too small: “At that time, trying to identify the microscopic larvae, which had never previously been identified as causing human infection, was a bit like trying to find a needle in a haystack.” But no one can explain how it migrated all the way to the brain.
Is this a whole new risk for humans?
Experts say there is no reason to panic about a widespread epidemic of worms in the brain. In one sense, this was a rare case of bad luck:
A lot of the parasites that can affect people do so because we get in the wrong place at the wrong time. So we ingest some eggs that aren’t supposed to come into us, and if we’re immunocompromised then we can have a pretty serious infection.
Good hygiene—like washing your hands after using foraged greens and veggies—and keeping your kitchen clean helps prevent most such disasters. Also: worms don’t jump from one person to another unlike a virus—so there is no fear of rapid spread.
As for worm infections: Human bodies are often invaded by all sorts of worms—which cause varying kinds of disease:
- Roundworms infect hundreds of millions of people around world—causing stomach pain, vomiting, diarrhoea, fever, and tiredness
- Pinworms infect around one billion people—cause intense itching in the anus.
- Giardia is a water-borne parasite linked to poor sanitation. It causes stomach symptoms like diarrhoea, cramps, bloating, nausea and fatigue.
- Hookworms cause anaemia and can prevent blood-clotting.
- Babies can be born with serious eye or brain damage if their mothers are infected with toxoplasma during pregnancy.
Beware the tapeworm: If you must worry about worms, then the worst are tapeworm larvae—not adult worms—which are often found in the brain:
These parasitic worms are best known in their adult stage, when they live in people’s intestines and their ribbon-shaped bodies can grow as long as 21 feet. But that’s just one stage in the animal’s life cycle. Before they become adults, tapeworms spend time as larvae in large cysts. And those cysts can end up in people’s brains, causing a disease known as neurocysticercosis.
And these are a leading cause of epilepsy.
The bottomline: While roundworms in the brain are rare, this case is a serious warning about the new kinds of disease caused by humans spreading into wildlife habitats. In the last 30 years, there have been 30 new infections—of which 75% are zoonotic. That means they spread from animals to humans. And if a zoonotic disease is new or rare, it may never be diagnosed—because physicians don’t know what to look for.
Reading list
The best overviews of the case are in the Washington Post, New York Times and CNN. The Conversation has more on common worm infections—and how to protect yourself. If you want to scare yourself, read Discover Magazine on the prevalence of brain infections caused by tapeworms. Associated Press links increases in infectious diseases to climate change.
