A 35-year-old French woman went to the emergency room after feeling “electric shocks” in her legs. For months, she had been experiencing worsening symptoms, which made it difficult to ride her horse and had caused repeated falls.
But at the hospital, she got an answer she probably wasn’t expecting. Doctors at the Centre Hospitalier Universitaire de Dijon in Dijon, France discovered a parasite had made its way to her 9th vertebra.
According to the case report published in this week’s New England Journal of Medicine, lab tests revealed the unnamed woman had a high white blood cell count, which can be a sign of an infection. An MRI tipped doctors off to a lesion on her spine, which then had to be removed surgically. After testing the lesion, doctors confirmed it was a cyst formed by the larva of a kind of tapeworm called Echinococcus granulosus, a condition known as cystic echinococcosis.
Echinococcus granulosus is most commonly found in dogs, who often get it from other animals, particularly sheep and cattle, according to the Centers for Disease Control and Prevention (CDC). For this parasite to infect a human, a person might touch an infected dog or its droppings, then touch their face, accidentally ingesting the tapeworm in the process. Or they might eat food or drink water contaminated by an infected dog’s poop.
Once swallowed, Echinococcus granulosus can grow into cyst-like lesions, called cystic echinococcosis or CE, according to the CDC. “Infection can cause cystic lesions in the liver and lungs and also in the central nervous system and bones,” the case report authors wrote. The slow-growing cysts may not result in any symptoms, possibly for years.
The woman in the case report had contact with cattle and had a pet cat, both possible sources of her Echinococcus granulosus infection. In addition to her surgery to remove the cyst, she was also treated with an antiparasitic medication. And there’s a happy ending: “At follow-up 9 months after presentation, the patient had no residual symptoms or sign of recurrence,” the authors wrote.
Of course, it’s better to never have a parasite to begin with. If you live in an area with sheep or cattle, always wash your hands thoroughly after touching dogs and before eating, the CDC recommends. It’s probably also a smart idea not to eat any greens or berries gathered from fields where dogs might be doing their business.