Humans can get a tapeworm in their brain through a condition called neurocysticercosis. This typically occurs when a person ingests the eggs of the pork tapeworm (Taenia solium), usually via:

1. Contaminated Food or Water: Consuming food or water contaminated with feces from an infected person.
2. Poor Hygiene Practices: If an infected person handles food without proper handwashing, the eggs can be transferred to the food.
3. Undercooked Pork: Eating undercooked pork infected with the larval cysts of the tapeworm can lead to infection, though this is less common for neurocysticercosis as the larvae typically develop in muscles, not the brain.

Once ingested, the eggs hatch into larvae, which can enter the bloodstream and travel to various parts of the body, including the brain. There, they form cysts, leading to neurocysticercosis. Symptoms can include headaches, seizures, and neurological deficits, depending on the cysts’ location and size. Proper cooking of pork, good hygiene, and safe food practices are crucial in preventing this infection.