(Picture of tapeworm brain cysts from Theodore E. Nash, M.D.)
The new science-fiction movie "Prometheus" just arrived in theaters. The movie is an Alien prequel, and the Aliens movies always bring to mind the image of the alien face-sucker latched on to some poor dude's face. He screams and tries to peel it off, but can't, and it implants an alien in him.
It's the sort of thing that makes your stomach hurt.
The good news is we haven't encountered any such aliens (yet). The bad news is we have plenty of weird creatures here on Earth waiting to invade your brain. Let's look at some examples!
Ever eaten undercooked pork? Next time you're eating barbeque, make sure it's cooked done. In the usual process, a person who eats undercooked pork may also eat tapeworm cysts found in the meat. Eventually, these cysts grown into tapeworms in the person's intestines.
But here's the twist. As that infected person poops, their poop contains tapeworm eggs. And if the person has those eggs on their hands when they prepare food for others (whether at home or in a restaurant), the eggs get into people's food. The eggs then travel through the bloodstream where they can end up in your brain. They grow into cysts that can cause blindness, fluid on the brain, seizures, coma and even death.
According to the National Institute of Health (NIH), there are millions of cases of this disease worldwide. (The formal name is neurocysticercosis.)
What's more fun on a hot summer day than plunging into your local swimming hole? You may want to pinch your nose or wear a nose clip. Naegleria fowleri is an amoeba that can enter through the noses of people who swim in warm, stagnant ponds. Although rare, if this amoeba works its way up to your brain, it causes flu-like symptoms, followed by seizures and loss of balance. Without medical attention, the victim will die in less than two weeks.
(On a side note, doctors now warn Neti pot users to use distilled or boiled water to flush their sinuses, and to keep the Neti pot clean and air dried.)
Parasites and amoeba can do more than just kill us. They can also affect our brains in less lethal ways. If you eat unwashed vegetables with cat poop on them, or eat raw or undercooked meat, you might also get toxoplasmosis (or Toxoplasma gondii). Toxo is a parasite that can form brain cysts.
Toxo affects the production of dopamine, which is an important chemical in your brain. There is a statistical link between cases of the mental illness schizophrenia and toxo, and dopamine plays a role in both. Healthy people may carry this parasite and be unaffected, but pregnant women and people with weakened immune systems are at risk. This is why doctors tell pregnant women not to change the cat litter box.
What can you do? Well, this information may freak you out, but it shouldn't. A lot of these problems can be avoided by washing your hands, washing your food, and cooking your food until it's done.
Above all, avoid visiting planets full of alien face-suckers.