How the parasite that RFK Jr. said he contracted infects the brain

A little-known parasitic infection in the brain received a jolt of attention Wednesday when presidential candidate Robert F. Kennedy Jr. said he once suffered from it.

The condition, known as neurocysticercosis, is a brain infection linked to larvae from pork tapeworms. It's rare: It hospitalizes roughly 1,000 to 2,000 people every year in the U.S.

Neurocysticercosis causes seizures, headaches, blindness, blurred vision, dizziness, psychosis or memory loss. In some cases, it may even be fatal.

The infection typically follows a sequence of events: People eat raw or undercooked pork that carries...