For many years, a Chinese man in the U.K. experienced a range of debilitating neurological symptoms with no understood origin–including headaches, memory loss, and seizures. A biopsy found inflammation in the man’s brain, but they were unable to pinpoint the exact cause of his symptoms.

Then in one final biopsy, surgeons unearthed the source of the man’s neurological issues; they pulled out a tapeworm that had been crawling through the patient’s brain for the past four years. The centimeter-long parasite had travelled more than 2 inches from the right side of his brain to the left, before it was successfully removed through surgery. Now, the patient is doing just fine.

Researchers from the Wellcome Trust Sanger Institute successfully mapped the genome of this man’s particular tapeworm, revealing it to be an extremely rare species known as Spirometra erinaceieuropaei. It marked the first time this species of tapeworm had ever been sequenced, and researchers hope its genetic information will help clinicians better diagnose and treat this parasite infection and others like it in the future.

The research indicates that the tapeworm is resistant to albendazole, a widely used anti-tapeworm drug. Now with this tapeworm’s genome mapped, researchers can pinpoint new drug targets in the worm that might be effective – both for Spirometra erinaceieuropaei and other tapeworms like it.

Read full original article: Worm living in human brain gets its genome mapped