A Nashville woman says a sushi dinner in February 2025 preceded months of severe vertigo, sensory problems, and brain fog before doctors eventually identified what she describes as a parasitic infection. In September 2026, TikTok creator Katherine Firsching (@katherinefirsching) documented the experience in a four-part series. In her first post, she said she ate sushi from what she described as a “reputable restaurant” on Feb. 4, 2025. About an hour later, she developed a burning sensation in her stomach and then spent roughly two days vomiting and feeling severely ill. Firsching said her symptoms changed after that initial illness. Within days, she experienced an episode of intense vertigo at work that lasted about three hours. Over the following months, she said the dizziness became more persistent and was accompanied by a sensation of floating while walking, extreme sensitivity to light and sound, an unusually strong sense of smell, and persistent nausea. The symptoms changed in the fall. By the fall, Firsching said, her symptoms had become severe enough that she could not drive for a week or leave her apartment normally. Firsching said emergency and urgent-care evaluations, including heart monitoring, an EKG, an ultrasound, and X-rays, could not identify the cause. @katherinefirsching One sushi dinner changed my life for the next 17 months. I wish I were exaggerating. Here’s the story… #healthjourney #medicalmystery #dizziness #chronicillness #parasite ♬ original sound – Katherine Firsching She later saw a vertigo specialist, who diagnosed her symptoms as vestibular migraine, according to Firsching. She said she had never experienced migraines before and did not believe she had identifiable triggers. Vestibular migraine can cause vertigo without a typical headache. The American Migraine Foundation says vestibular migraine can cause vertigo along with symptoms such as sensitivity to light and sound, while migraine more broadly can involve nausea and sensitivity to smells. Firsching eventually underwent vestibular rehabilitation. She described testing with a rotary chair and VR goggles and said the treatment temporarily left her extremely fatigued. She later took medical leave from work. Doctors diagnosed Firsching with a parasitic infection. Her symptoms eventually led her to another doctor, who she said performed extensive testing. Around June, Firsching said she was told she had an “extreme parasitic infection.” She identified the parasite as a liver fluke and said she believed she contracted it from the sushi. The Centers for Disease Control and Prevention (CDC) says certain liver flukes, including Clonorchis and Opisthorchis, can infect people who eat raw or undercooked freshwater fish from regions where those parasites occur. Their typical symptoms involve the digestive system and the liver, gallbladder, or bile ducts. The CDC does not describe liver fluke infection as a general cause of chronic vertigo or sensory hypersensitivity. Likewise, the CDC identifies anisakiasis, another parasitic infection associated with raw or undercooked fish, as causing primarily gastrointestinal symptoms such as abdominal pain, nausea and vomiting. Firsching said she underwent an intensive treatment regimen and began feeling more like herself around August 2026. She said she still had some recovery ahead but had started to see improvement. The FDA says some fish can contain parasites and recommends cooking seafood thoroughly to minimize the risk of foodborne illness. For people who choose to eat raw fish, the agency says previously frozen fish can reduce the parasite risk, although freezing does not kill all harmful germs. Firsching said her experience changed her attitude toward sushi, adding that she would “probably never eat sushi again.”