It all began with an unusual burning sensation in her feet. Within two days, the intense pain began to extend up her legs. Even the slightest touch exacerbated her discomfort, and over-the-counter pain relief proved ineffective.

By the third day, the 30-year-old woman from New England, who had previously enjoyed good health, sought help at an emergency room. Her examination yielded normal results, and her blood work and kidney function appeared satisfactory. The only notable finding was a significantly elevated level of eosinophils, a type of white blood cell that can spike in response to allergies, parasitic infections, or other medical issues, including some cancers. She was discharged with recommendations to check in with her primary care physician.

As the days progressed, the burning sensation continued to spread, reaching her trunk and arms. She also developed a persistent headache that was resistant to over-the-counter medication. After a week of enduring these symptoms, she returned to another emergency room. Once more, the findings were similar: normal examination, normal blood tests, normal kidney function, and a significantly increased eosinophil count—this time rising to 1,050, well above the typical range of 0 to 400. She received intravenous treatment for her severe headache but was again discharged with guidance to consult her primary care doctor.

Back at home and still struggling, she was given a prescription sleep aid by a family member to help her rest. However, the next day, she woke up in a confused state, insisting that she needed to pack for a vacation and was resistant to suggestion. After hours of this bewildered behavior, her partner took her to a third emergency department, this time at Massachusetts General Hospital.

A Step Closer to a Diagnosis

According to a case report in the New England Journal of Medicine, the medical team was able to identify the source of her distressing symptoms—parasitic worms that had invaded her brain. By this stage, she was alert yet disoriented, struggling to respond to questions and follow instructions.

The doctors at Mass General, including a neurologist with expertise in infectious diseases, quickly noted that she had recently traveled abroad. Just four days before the onset of her symptoms, she had returned from a three-week journey that included visits to Bangkok, Thailand; Tokyo, Japan; and Hawaii. They inquired about her meals during her travels. In Thailand, she had indulged in street food but avoided anything raw. In Japan, she relished sushi multiple times and primarily stayed in a hotel. While in Hawaii, she again chose sushi along with salads.