A man was hospitalized with worsening migraines only to find out they were caused by parasitic tapeworm larvae in his brain — and researchers believe he was infected by eating undercooked bacon.

The unidentified 52-year-old American man consulted doctors about changes in his usual migraines over four months, according to a study in the American Journal of Case Reports published Thursday. The migraines became more frequent, severe and unresponsive to medication.

The patient was admitted to the hospital for testing. CT scans revealed numerous cystic foci, which are fluid-filled sacs in the brain. Cysticercosis cyst antibody tests returned positive, and the man was diagnosed with neurocysticercosis, the study said.