Tapeworms on the brain

Here's a fun fact: Did you know that you can get tapeworms in your brain? You know that you can get a tapeworm from eating infected meat. But when people have tapeworms in their guts, they secrete tens of thousands of eggs a day. And those eggs can end up on food, or other things that people put into their mouths. For some reason—nobody is really sure why—tapeworm eggs that are ingested by humans never mature into adults. Instead, they remain in a larval stage and hang out in a host's bloodstream. Sometimes, they make it to the brain. And, apparently, this happens often enough that it has an actual medical name: Neurocysticercosis.

The good news is that these things are mostly harmless. They don't seem to hurt your brain at all while they're alive. The bad news: As soon as the larvae die, your body's immune system seems to suddenly realize they exist and it goes into overdrive—triggering seizures, loss of feeling in the body, and sometimes leading to death.

Scientific American blogs has the story of one woman in California who had this happen to her. To save her life, surgeons had to remove a calcified tapeworm larva from her brain.

Sara Alvarez was afraid.

It was December 20, 2010, in Sunnyvale, Calif., a town that lives up to its name. The West Coast winter, not as long or as harsh as seasons in the East, gave her the opportunity to take her youngest child out for an afternoon stroll.

In the fading light of dusk, Alvarez, too, began to fade. She lost the feeling in her right leg. Her right foot followed suit. She couldn’t lift or move her right hand. She was weak, and her body was numb.

The National Institutes of Health classifies neurocysticercosis as the leading cause of epilepsy worldwide, and the World Health Organization (WHO) estimates that tapeworms infect 50 million people globally. The CDC says an estimated 1,900 people are diagnosed with neurocysticercosis within the United States yearly.

Read the rest of the story at Scientific American blogs. (WARNING: Surgery images!)

35

  1. Maggie, we know very well why ingested tape worm eggs never turn into full adults.  Tapeworm eggs hatch into juveniles, which invade muscle tissue.  Later, when the host is eaten, the encysted juveniles mature into adult tapeworms which occupy the intestines.  This is their normal life cycle, not some unknowable quirk.  Can I recommend that you listen to This Week in Parasitism, hosted by the inventor of vertical farms, Dickson Despommier? It is easily the best podcast in all existence, and will have you falling in love with tapeworms by the end of if.

    1. Yeah… not that it ever was on my list, but yeah… scratch it off… no, burn it off!!!

      “The National Institutes of Health classifies neurocysticercosis as the leading cause of epilepsy worldwide, and the World Health Organization (WHO) estimates that tapeworms infect 50 million people globally. The CDC says an estimated 1,900 people are diagnosed with neurocysticercosis within the United States yearly.”

      Say whaaaaat???? Leading cause of epilepsy worldwide??? 1,900 cases of neurocysticercosis a YEAR in the US???? Ewwwww… but as a leading cause of epilepsy, how isn’t there more noise about this? (I assume because it is in non-first-world-countries mostly.)

    1. To be clear: the picture above is of post-op stitching and not of a worm bulging beneath the skin, right?

      Bless the Maker and his water.
      Bless the coming and going of him.
      May his passage cleanse the world.

  2. During the course of a natural lifecycle, the proglottids are discarded through their host’s anus. A family member, friend or restaurant cook infected with an adult tapeworm can secrete tens of thousands of tapeworm eggs daily, which can be easily ingested by others.

    I’m having trouble seeing the “easily”.

    1. The infected person doesn’t wash their hands properly after using the bathroom, so the eggs are still on their hands when they do something like make you a sandwich. Same way GI viruses are easily transmitted.

      (And yet, probably 90% of people I see in public restrooms don’t wash their hands with soap. Most people just run their hands under the water for a second and go.)

  3. As FDR put it, “The only thing we have to fear is fear itself. Also, tapeworms laying eggs in our brains.”

    I’d like to believe that this is as bad as it gets, but if I say anything to that effect Maggie will discover some kind of parasite that hatches in your sinuses, emerges from your eyeball, climbs down your face and eats your tongue before laying its eggs in your lungs. And I don’t want to hear anything about that one, understand? 

    1. Cymothoa exigua is the tongue-eating one you want, or rather don’t want. It eats a fish’s tongue and then lives in the mouth pretending to be one.  Warning: If you search for and find pictures of it, you won’t be able to unsee them. 

    1. You can get the eggs through somebody who has an infection (for instance, doesn’t clean their hands properly after going to the bathroom and then prepares the food you eat). But these would only become larvae (the ones discussed here in the article).

      You would probably be protected from eating the larvae cysts, which would then grow into an adult tapeworm (the long thingy you usually see pictured).

  4. Ahh neurocysticercosis… a somewhat common finding at my old ER when we would CT scan trauma patients.  Maybe not once per weekend, but once per month seems a reasonable memory.  It was much much more common in the Mexican immigrant population, which always made us wonder about diet & cooking habits in people’s home towns.  Most anitbiotics kill the larvae, but as the article notes, the scarring seems just as or more causal to the seizures (what a terrible sentence, but I can’t seem to finesse the grammar tonight).  One friend always claimed it was mostly from undercooked pork, but I never saw research that honed in on a particular food vector.

    The FiatRN
    Denver, CO  

Comments are closed.