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MEDICINE 101

Worms

This is an earthworm. Fish love the taste and so they get hooked, landed, fried up and eaten. But, in an ironic twist of nature, sometimes the fish get their revenge. This is another kind of worm … a dyphylobothrium latum, a fish tapeworm. The larva stage of the worm lives in the flesh of fish, particularly pike, salmon and pickerel.

And when we humans eat raw or uncooked fish the larva develops into a full-fledged tapeworm that takes up residence in our bowel. It can live there up to 30 years and grow to a length of 30 meters producing one million eggs a day, and it survives off the food we eat, including the fish.

But mainly when we humans talk about “worms” we’re talking about these – pinworms or threadworms known as enterobius. They’re very tiny, like little moving pieces of thread and they usually infect children. They’ve got an interesting story too. The adult pinworms live in the large bowel, and when the female is ready to lay eggs, she has a habit of exiting out the anus to deposit her eggs on the skin outside. She usually does this about an hour or so after the child goes to bed. Then the child wakes up feeling pretty uncomfortable, crying and scratching because the eggs are laid with an irritating glue. Of course all of this itching causes the eggs to spread – and there are a lot of them – a single female pinworm can lay ten thousand eggs a day. The eggs are so tiny and so light they can float on air. And then they’re ingested by another person; hatch in their bowel and the whole cycle is repeated. You can actually see the worms moving about on your child if you look with a flashlight. It’s a sobering moment for a parent.

But the king of worms, and certainly the most well traveled, is this one – Ascaris, the roundworm. It infects about one quarter of the world’s population. Each of these ((white looking)) worms can lay two hundred thousand eggs a day and, when the eggs are passed, they mature in the soil for a couple of weeks. And then when ingested, the larva grows into a small juvenile worm in the small intestine. Here’s where it gets to travelling. For some unknown reason, it moves through the wall of the intestine into the circulatory system, flows along with the blood to the lungs, and then enters the air spaces of the lungs. It crawls up the bronchi only to be swallowed again into the stomach and end up exactly where it began. And no one knows why. But it produces some of the symptoms of Ascaris infection such as coughing, strains of pneumonia and even coughing up white worms such as this. The worm itself can produce malnutrition, anemia and even bowel obstruction if a whole clump of worms get together and block off the bowel.