How do the worms get into our brain, causing so-called neurognathostomiasis? Gnathostoma worms are highly invasive parasites. After you leave the sushi bar, the larvae can penetrate the wall of your intestine. They can then enter the brain through the base of the skull, crawling along the spinal nerves and vessels. They start out in the nerve roots, enter the spinal cord, and then can climb up into the brain. The worm isn’t poisonous or anything; it’s just the migration of the worm through the body that causes direct mechanical injury because of tearing of nerve tissues.
I’ve said it before and I’ll say it again.
Sushi would be fine if you cooked it.