Researchers from the Australian National University (ANU) and Canberra Hospital have identified the world’s first case of a new human parasitic infection. It involves a live roundworm known as Ophidascaris robertsi, which was extracted from the brain of a 64-year-old Australian woman. This case sheds light on the dangers of zoonotic diseases, which are caused by pathogens transmitted from animals to humans.
The woman became infected with the roundworm O. robertsi after picking varigala greens, a spinach-like native plant, from a nearby lake that is home to carpet pythons. Although the woman had no direct contact with the snakes, it is believed she contracted the parasite either through touching the plant or unknowingly eating its eggs. Roundworms usually live in the esophagus and stomach of carpet pythons, and their eggs are excreted with the snake’s feces.
“This is the world’s first human case of Ophidascaris,” said Sanjaya Senanayake, corresponding author of the study. “To our knowledge, this is also the first case of brain lesions in mammals, both human and other species.”
The woman first developed abdominal pain and diarrhea, followed by fever, cough and shortness of breath. These symptoms were later attributed to the migration of roundworm larvae from the intestines to other organs such as the liver and lungs. Despite respiratory sampling and lung biopsy, no parasites were found in these specimens. The microscopic larvae responsible for the infection were difficult to identify at that time.
In 2022, after three months of forgetfulness and worsening depression, the woman underwent a brain MRI that revealed a lesion in the right frontal lobe. An open biopsy was performed, which revealed a roundworm measuring 3 inches (8 cm) in the brain. The parasite was extracted alive and wriggling. Parasitology experts confirmed its identity.
After removal of the roundworm, the woman was treated with antiparasitic drugs and dexamethasone to eliminate the possible presence of larvae in other organs. It is known that Ophidascaris larvae can live in the organism of animal hosts for a long time, sometimes exceeding four years.
This unusual case highlights the risks associated with zoonotic diseases. “In the last 30 years, there have been about 30 new infections worldwide,” Senanayake explained. “Of all the new infections in the world, about 75% are zoonotic, i.e. transmitted from animals to humans.”
While this particular infection cannot be transmitted from human to human, it serves as a reminder of the potential dangers posed by zoonotic diseases. Vigilance and awareness are critical to preventing and treating such infections.
