A neurosurgeon in Australia pulled a live, three inch-long worm from the brain of a 64-year-old woman in June 2022. The roundworm Ophidascaris robertsi is native to Australia and its larvae were also present in other organs in the patient’s body, including the liver and lungs. This is the first known human case of this parasitic infection and it is described in a case study published in the September 2023 issue of the journal Emerging Infectious Diseases.
The patient was first admitted to her local hospital in late January 2021 after experiencing three weeks of diarrhea and abdominal pain, followed by dry cough, night sweats, and fever. By June 2022, she was also experiencing forgetfulness and depression, and was referred to Canberra Hospital. While there, she underwent brain surgery when an MRI revealed some abnormalities.
Neurosurgeon Hari Priya Bandi was performing a biopsy when she used forceps to pull the parasite out of the woman’s brain. She immediately contacted Canberra Hospital infectious diseases physician Sanjaya Senanayake, saying “Oh my god, you wouldn’t believe what I just found in this lady’s brain—and it’s alive and wriggling,” Bandi said, according to The Guardian.
According to the case study, this is the first known human Ophidascaris infection and the first to involve the brain of a mammalian species. These worms are common to carpet pythons and they typically live in a python’s stomach and esophagus. Humans infected with Ophidascaris robertsi larvae would be considered accidental parasite hosts.
“Normally the larvae from the roundworm are found in small mammals and marsupials, which are eaten by the python, allowing the life cycle to complete itself in the snake,” Senanayake, who is also one of the co-authors of the case study, said in a statement.
The researchers believe that the woman from southeastern New South Wales likely caught the roundworm after collecting Warrigal greens next to a nearby lake where a python had shed the parasite via its feces. The patient used the Warrigal greens for cooking and was probably infected with the parasite directly from touching the native grass or after consuming the greens.
According to the team, this world-first case highlights the danger of zoonotic transmission, or diseases and infections that pass from animals to humans. This risk is growing as humans and animals start to live more closely together and habitats continue to overlap.
“There have been about 30 new infections in the world in the last 30 years. Of the emerging infections globally, about 75 percent are zoonotic, meaning there has been transmission from the animal world to the human world. This includes coronaviruses,” Senanayake said. “This Ophidascaris infection does not transmit between people, so it won’t cause a pandemic like SARS, COVID-19, or Ebola. However, the snake and parasite are found in other parts of the world, so it is likely that other cases will be recognised in coming years in other countries.”
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The patient was sent home following the surgery with antiparasitic drugs and has not returned to hospital since, but they are monitoring her since this is such a new infection.
Despite this case being extremely rare and spine-tingling, parasitic infection is actually extremely common. One of the most widespread types is pinworm (Enterobius vermicularis or threadworm), and some estimates say it is present in over one billion people around the world. They are specific to humans and can cause intense itching and are passed from person-to-person.
Two types of hookworm—Necator americanis and Ancylostoma duadonale—are found in soil. Ancylostoma duodenale only lives in Australia typically in more remote communities. These worms typically enter the bloodstream through the feet.
According to Vincent Ho, an associate professor and clinical academic gastroenterologist at Western Sydney University, the best ways to avoid a parasitic infection include avoiding undercooked or raw pork, avoiding swimming or jumping into warm fresh bodies of water, practicing good hand washing, and wearing shoes in rural areas.