Seven years ago, Leah Ankers, a dog groomer living in Texas, noticed a rash on her leg in the shape of a perfect circle. She didn’t think much of it.
"I’d had ringworm before from grooming," she said recently, "so I figured that’s all it was."
So did her doctor. She was prescribed a topical medication, but strangely the rash still wasn’t gone after a month. Yet it wasn’t itchy, so Ankers, then age 19, assumed the medication was working.
Around that same time, she “started to become a different person.” Suddenly she became moody and irrational. Her head hurt. Her joints swelled. She grew so exhausted that walking from her car to her apartment put her out of breath.