This Woman Had Diarrhea, Abdominal Pain For Weeks, Turns Out, It Was A Living Worm In Her Brain

For a 64-year-old woman in southeastern New South Wales, Australia, what began as normal digestive complaints escalated into a strange and frightening medical enigma. Weeks of recurring stomach cramps and diarrhea became night sweats and a chronic dry cough. Physicians first suspected infection, as lesions cropped up on her lungs, liver, and spleen. But each test—bacterial, fungal, parasitic, and even autoimmune tests—was negative, further clouding the mystery.

Three weeks later, her condition deteriorated. A severe fever and a worsening cough had her back in the hospital. A key piece of evidence was discovered when physicians observed that certain of the lesions in her lungs seemed to be migrating. At the time, though, no one could have anticipated the astonishing revelation that awaited them.

During the next few months, the woman's symptoms spilled over into her overall health. She started having serious memory problems, heightened forgetfulness, and even depression. Her general practitioner (GP) sensed something was seriously amiss and arranged for an MRI scan of her brain. What the physicians discovered was frightening—a lesion in her frontal lobe that lit up darkly on the scan.

At this stage, experts were considering several options: cancer, an abscess, or another neurological disorder. But the real reason was something nobody had expected. "No one thought it was going to be a worm," said Dr. Sanjaya Senanayake, a Canberra Hospital and Australian National University infectious disease specialist.

In June 2022, the patient's medical team took a biopsy of the lesion. What they removed left them stunned: a live, red, three-inch-long parasitic worm. An Ophidascaris robertsi roundworm, a worm typically encountered in Australian carpet pythons, had infested the woman's brain.

The parasite's normal life cycle includes pythons expelling eggs in their stools, which are swallowed by small mammals like possums or rodents. These intermediate hosts carry the larvae in their bodies before they are consumed by pythons and get deposited in feces to continue the process. Human beings are not normal hosts but are merely accidental ones, and infection is very rare.

How Did the Parasite End Up in Her Body?

Although the precise route of transmission is unknown, physicians believe that the woman unknowingly ingested eggs from the parasite. She resided close to a lake home to carpet pythons and regularly hunted for native warrigal greens—a leafy green vegetable approximating spinach. If the greens contained eggs from the feces of the python, or her hands or kitchen surfaces had eggs, she may have unknowingly ingested them.

The case of the woman, which was published in Emerging Infectious Diseases, a CDC journal, was the first reported instance of an Ophidascaris worm infesting a human. Although roundworms infest millions globally, the species had not been detected previously in humans.

Scott Gardner, a University of Nebraska-Lincoln parasitologist, was quick to stress that while the case is worrisome, it is not a public health epidemic in general. "There is no reason for people to panic that they are infected by Ophidascaris through snakes," Gardner said. "Good hygiene can prevent parasitic infections.".

The female's earliest signs—fever, lung infections, and diarrhea—must have been because of the larval migration from her intestines into other parts of her body, such as her liver and lungs. Picking up those minuscule larvae in an early stage proved extremely difficult, however. "Attempting to catch the larvae that far along in development was trying to find a needle in a haystack," stated Canberra Hospital Director of Microbiology Dr. Karina Kennedy.

After the brain worm was detected, the woman was operated upon to have the worm removed. While the operation was a success, she continued to be monitored closely by the doctors, for they suspected there could be still larvae in the other organs. She was treated with antiparasitic medication to eliminate the remaining worms, if any, and avoid future complications.

Are Humans at High Risk of Zoonotic Infections?

This case highlights the increasing alarm over zoonotic diseases—diseases that leap from animals to humans. The CDC reports that about 60% of all infectious diseases and 75% of emerging diseases come from animals. With human activities more and more intruding on wildlife habitats, such infections could become more common.

Though Ophidascaris worms are endemic to Australia, similar roundworm species infest snakes all over the globe. This situation prompts a vital question: Are such infections possible in humans in other parts of the world? Scientists now urge heightened surveillance on parasitic infection and its capacity to cross species.

Although uncommon, this incident is an important reminder of the need for hygiene when preparing food, particularly wild-foraged vegetables. Experts advise the following precautions:

Wash Hands Thoroughly: Wash your hands thoroughly after gardening, working with raw vegetables, or touching soil.

Clean and Cook Foraged Foods Properly: Wash leafy greens, vegetables, and fruits thoroughly before eating. Cooking food at high temperatures can also destroy harmful parasites.

Avoid Consuming Raw or Unwashed Vegetables from Wild Habitats: If foraging in areas where wildlife lives, take special care regarding contamination.

Consult a Specialist for Ongoing Unexplained Symptoms: If gastrointestinal, respiratory, or neurological symptoms continue without a diagnosis, see a specialist.

Six months following her operation, the woman's neurological symptoms had eased, although she was still being monitored by medical personnel. Her experience is a harsh reminder that nature has secrets in abundance and at times the most unlikely suspects may be waiting in places we least expect to find them.