Worms and other Parasites
arasites are miserable little organisms that live off us. They vary from one-cell organisms, such as malaria and amoeba, to fully developed worms. Some migrate and live in our tissues, where they can damage us severely—especially if they get into our brains. Others are in our bowel, and yet others get into our lymphatics or skin.
The following questions illustrate the global problems with parasites.
My 7-year-old was coughing and vomiting, and a worm came out of his nose. It looked like an earthworm—only about two inches long and pink. Could you advise? I thought worms came from eating meat.
Some worms do come from meat. The pork tapeworm (or Taenia solium) and the beef tapeworm (Taenia saginata) come from eating meat that is infested with tapeworm cysts. Good, thorough cooking prevents these diseases, but so does being a vegetarian.
Your little boy’s worm was not a tapeworm. It was probably an Ascaris lumbricoides worm. These worms are the most common of all human worm parasites. More than a billion people have the worm in their intestines. The worm lives about one to two years. The female lays 200,000 eggs a day into the bowel content, which pass out in the stool. If a human eats the eggs by way of unwashed hands, food handling, etc., then a little larva hatches out of the egg. This larva bores into the intestinal wall, and travels in the veins to the heart and then the lungs. It then bores from the blood vessels into the air sacs.
The worm climbs the respiratory tubes and is swallowed and restarts the cycle. Such worms can be so abundant they can block the intestine, causing vomiting. Children sometimes vomit up a worm, which could come out the nose. The worm also causes lung inflammation, but this is because the larvae are passing through the lungs.
What an important lesson to us about washing our food—and especially our hands! It’s not nice to think we eat eggs from someone else’s bowels, but a billion people obviously have done so.
My mother always makes me wear shoes, and half the other kids in our village go barefoot. The weather is warm in Zambia, and I think she is being overprotective. Don’t you?
You are living in the tropics. Lucky you! But that warm, humid weather is good for some miserable little organisms that are mean parasites. There are several worms that can live in us and in the soil that we need to be aware of.
One worm that can bore through your skin and infest you is the hookworm. About a quarter of the world’s population is affected by hookworms. They burrow through the skin, go to the lungs, then crawl into the respiratory tubes and climb up into the throat, where they are swallowed. Then they hook on to the small intestines and suck blood. These little bloodsuckers lay eggs that are passed in the feces. That is why latrines are so important, because unless we control human feces, we have no hope of controlling some of these diseases. Of course, it helps to wear shoes! So guess what? Your mom is correct!
We live in a beautiful part of Canada, and a beaver pond is at the bottom of the hill. Our grandchildren visit us, and want to swim in the pond. Is there any danger?
Parasites are organisms that live inside or on another organism and give nothing in return. In fact, some can be very harmful to humans. “Beaver fever”—as the parasite infestation with Giardia lamblia is called in Canada—is not a nice illness. Beavers may have giardia and contaminate beaver ponds with it. Giardia causes diarrhea, abdominal cramping, and foul-smelling gas. The diarrhea can last a long time (weeks) and cause weight loss.
While we may sound like spoilsports, we have to be wise. Swimming in lakes or rivers in Canada would be much less of a risk than swimming in a beaver pond.
–Allan R. Handysides, M.B., Ch.B., F.R.C.P.,
is director of the General Conference Health Ministries Department.
–Peter N. Landless, M.B., B.Ch., M.Med., F.C.P.(SA), F.A.C.C.,
is ICPA executive director and associate director of Health Ministries.