Woman’s series of odd symptoms were from 3-inch worm living in her brain

A 64-year-old Australian woman is the first documented human to be infected with a type of parasite normally found in carpet pythons. Doctors extracted a 3.1-inch living roundworm from her brain after more than a year of worsening symptoms, according to a case study in the journal Emerging Infectious Diseases.

It also may be the first-ever case of this type of roundworm infecting the brain of any mammal, according to a press release.

In January 2021, the woman, who lives in New South Wales, visited her local hospital because of stomach cramps, diarrhea, night sweats and a dry cough. Doctors treated her and sent her home with prednisolone, a type of steroid. She returned to the hospital three weeks later with fever and continued coughing. At the time, doctors suspected she might’ve had a parasite and treated her for it.

However, her symptoms never improved. In 2022, she became absentminded and depressed. A brain MRI detected what seemed like a mass with a “stringlike structure” in it, according to the case study. When doctors biopsied it in June 2022, they found an 8-centimeter living worm in the right frontal lobe of her brain.

Neurosurgeon Dr. Hari Priya Bandi recalled the moment she found the worm in the woman’s brain to BBC: “I was able to really feel something, and I took my tweezers, and I pulled it out, and I thought, ‘Gosh! What is that? It’s moving.’ … Everyone was shocked. And the worm that we found was happily moving, quite vigorously, outside the brain.”

The parasite is an Ophidascaris robertsi, a type of roundworm that lives in carpet pythons. The journal article noted that the woman had “no direct snake contact,” but often foraged for greens near a lake where carpet pythons are known to live. The doctors suspect that she accidentally ingested the worm’s eggs from eating the greens or through kitchen cross-contamination.

“It’s not meant to develop in her. It’s meant to develop in small mammals and marsupials,” Dr. Sanjaya Senanayake, an infectious disease expert in Canberra Hospital, who was involved in the woman’s care, told NBC News. “She was an accidental host.”

The worm, a third-stage larvae, traveled through the woman’s body and finally nestled in her brain. “In retrospect, (her) symptoms were likely due to migration of roundworm larvae from the bowel and into other organs, such as the liver and the lungs,” explained Dr. Karina Kennedy, Canberra Hospital’s director of clinical microbiology, in a press release.

Researchers also noted the patient was immunocompromised, which may’ve helped the worm get into her central nervous system, which include the brain and spinal cord.

After the worm was discovered and removed, the patient was again treated for parasitic infection in case any eggs lingered in her body. The larvae of this type of roundworm have been known to last for years in animal hosts, according to the case study.

The patient is still being monitored by infectious disease and brain specialists.

Senanayake said he suspects such novel parasitic infections will occur more often as humans move into animals’ environments, often due to climate change. About 75% of documented, new infections have traveled from animals to humans, he added.

While he doesn’t expect this type of parasite to cause the next pandemic, he said he does expect to see more cases in other countries where carpet pythons reside.

The most important message from this case is about food safety, Kennedy said: “People who garden or forage for food should wash their hands after gardening and touching foraged products. Any food used for salads or cooking should also be thoroughly washed, and kitchen surfaces and cutting boards, wiped downed and cleaned after use.”