Carl Zimmer ensures you'll have trouble sleeping at night:
Before they become adults, tapeworms spend time as larvae in large cysts. And those cysts can end up in people’s brains, causing a disease known as neurocysticercosis. … As a tapeworm cyst grows, it may push against a region of the brain and disrupt its function. It may get stuck in a passageway, damming the flow of cerebrospinal fluid. This impasse can cause hydrocephalus, or water on the brain, along with dangerously high pressure. A resulting brain hernia can result in stupor, coma, or death.
Cassie Murdoch is aghast at the estimates in developing countries:
You really need a brain scan and blood tests to confirm a diagnosis, and this isn't usually done in the areas where the disease is most common. But Nash and some colleagues set about traveling in Latin America giving scans and doing the tests, and they found in Peru, for instance, that 37 percent of the people they tested showed signs of being infected at some point. Ahhhh! They've also done a review of scientific literature and figured out that there are likely between 11 million and 29 million people in Latin America alone who have neurocysticercosis. That is insane.
(Image by Theodore Nash)