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5-Inch-Long Tapeworm Lived in Man's Brain for More Than a Decade

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A man in China experienced seizures and other mysterious symptoms for years before doctors finally found the cause: He had a rare parasite living in his brain, which had likely been there for more than a decade, according to news reports.

The man, who lives in Guangzhou, China, said that he began to feel numbness on the left side of his body starting in 2007, according to Fox News. In the following years, he developed more worrying symptoms, including blackouts and seizures, although doctors failed to find the true cause of his illness.

Then, in 2018, doctors discovered a nearly 5-inch-long (12 centimeters) tapeworm in his brain. He was diagnosed with sparganosis, an infection caused by a type of tapeworm larvae known as Spirometra.

Humans are rarely infected with Spirometra are rare — the parasite typically lives in the intestines of dogs and cats, according to the Centers for Disease Control and Prevention (CDC). Other hosts in the parasite's life cycle include fish, reptiles, amphibians and freshwater crustaceans. 

But humans can become infected if they drink water contaminated with the parasite, or if they eat undercooked meat from animals, such as frogs or snakes, that are hosts to the parasite. The parasite can live for up to 20 years in humans, the CDC says.

Although Spirometra tapeworms occur worldwide, most human cases have been reported in Southeast Asian countries, according to the CDC. Humans are accidental hosts and can't transmit the disease.

The Spirometra larvae can migrate anywhere in the body, including the eyes, urinary tract, lungs, abdomen and, as in this case, the central nervous system. Brain infections with the larvae can cause a variety of symptoms, including weakness, headache, seizures and numbness or tingling, the CDC says.

Doctors removed the tapeworm from the man's brain during a 2-hour surgery. "The surgery was risky," Dr. Gu Youming, the man's surgeon, told AsiaWire, according to Fox News. "The live tapeworm was moving in his brain, and we had to remove all of it, otherwise the leftover part could grow again."

In 2014, a similar case of a brain infection with Spirometra was reported in a man of Chinese descent living in England, according to The Guardian.

At that time, doctors involved in the case said that this type of tapeworm can survive in the brain by scavenging for fatty acids, which it absorbs through its body. "This worm is quite mysterious, and we don't know everything about what species it can infect or how," Dr. Hayley Bennett, who was involved in the 2014 case, told The Guardian.

Originally published on Live Science. 

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.