Intestinal Parasites: A Source Of Interest

Judging from the number of letters I receive on the subject, intestinal worms are a constant source of interest. And, naturally, of apprehension. For anyone to find that he has just expelled a round-worm or the segment of a tapeworm is naturally to be overcome with acute repugnance. There may be more inside of him. May be? Certainly are. This never happened to him before. It never happened in his family before. Heavens! Let’s do something right away. How do you get rid of them?

Yes, the fears are natural enough, but they may be easily allayed. Any intestinal parasite can be destroyed and cast out. We have many effective drugs for all of them.

How common are intestinal worms? We have little information on the subject. The answer depends on what geographical area is referred to. In Africa, especially Abyssinia, it is said that virtually every native has a tapeworm. This is the beef tapeworm. The reason for the prevalence of this infestation being that Abyssinia is a cattle raising country and the natives live in very close association with their animals and eat their flesh without proper cooking.

In the United States, a survey of 1,650 persons in North Carolina, in 1931, showed that 23 per cent had some form of intestinal parasites. Three hundred forty-seven had hookworm, 18 had roundworm, three had dwarf tapeworm, one had pinworm and three beef tapeworm.

In more northern climates there would be little or no hookworms but the other infestations would be about the same. This would be a percentage of about 1 1/2.

Again, this depends on what class of the population we examine. Among children living in crowded quarters, with unclean bed clothing, the number of pinworms would undoubtedly be much higher. Those living under conditions where animals—dogs, sheep or cattle—are around them all the time, are more likely to parasites because these animals are the intermediate hosts of the parasites. The places where echinococcus disease, due to the dog tapeworm, is endemic or regularly met with, are Norway and Greece, sheep raising countries, where the sheep dogs are on terms of complete intimacy with the shepherd families.

The hookworm is so small that we can hardly call it a worm at all, and although it constitutes a most important public health problem, we do not intend to include it in the study of intestinal worms in this article. When American troops first occupied Puerto Rico, they found almost the entire native population suffering from an anemia which produced extreme prostration. The medical department of the U. S. army, under the charge of the late Colonel Ashford, found that the cause was infestation with hookworm. By dosing the population wholesale with thymol, the disease was abated. Much the same conditions were found in parts of our southern states. While the condition still exists, as shown by the figures cited above, it can potentially be controlled.


Disgusting as the idea of having a worm inside the body is, the life history of these parasites is extremely interesting. All of the tape-worms are bisexual (hermaphroditic) and the one animal can produce a fertilized egg which is capable of developing into a new individual. Each segment of a tapeworm, indeed, is mostly reproductive organs; it contains no digestive system, because the worm absorbs all its nutriment from the food of its host, predigested.

A human being infected with a tapeworm cannot infect another human being. The eggs must undergo development in another animal. There are pork and beef tapeworms (the latter by far the more common in the United States) and the cycle of development is about the same in each. The mature segments or mature eggs are thrust out from the human intestine and lying on the grass or in the drinking water, are taken in by the pig or cow. In the alimentary canal of the animal, the eggs develop into little embryo worms which get out into the blood vessels around the intestines and are carried to the animal’s muscles. Here they form little cysts and develop into larval worms. Such meat is said to be “measly.” When it is eaten in an incomplete state of cooking—that is, when the larvae are not killed—the larvae develop into mature worms in the new host’s intestine.

The beef tapeworm may develop to a prodigious length—20 feet or over. The head is buried in the mucous membrane of the intestine and stays there by means of sucking discs or hooks. The pork tape-worm is called “taenia solium” because only one worm at a time develops in one person.

The symptoms of the presence of a tapeworm are very vague. The voracious appetite commonly ascribed to the association was not present in a large series of patients examined. But nervous indigestion and neurotic symptoms were common and cleared up on treatment. The diagnosis usually is made only when the patient notices that he has passed segments of a tapeworm.

Treatment is simple and effectual if carried out properly. There are many drugs that will kill a tapeworm without doing any harm to the body, in proper dosage. One of the best is pelleterine sulphate, the active principle of pomegranate.

A French physician, Professor le Dantec, had a tapeworm of his own and studied the living segments that were passed, by putting them in bouillon cultures. When he added very dilute solutions of pelleterine sulphate, he killed the segment.

The important thing is to expose the head of the worm, give the lethal drug, and then wash the worm, head and all, out of the intestine while it is still groggy. The head may be groggy, but not dead, and come to life and dig itself in again.

A liquid diet and a preliminary dose of salts will expose the worm. The pelleterine is given in two doses and then 30 to 40 minutes later (the time Professor le Dantec found to be the period in which the drug would act) a stiff dose of Glauber’s salts is given three or four times, at intervals of 15 minutes.

Other drugs may be used. A new one, hexylresorcinol, is effective and not poisonous to the host. In children, pumpkin seeds is an old and well-tried remedy.


The two commonest worms which act as intestinal parasites are the roundworm and the pinworm. They occur mostly in children.

The ridding of a patient of intestinal parasites has been considered a serious procedure for centuries, and there is a long list of drastic, and often poisonous, drugs which have been used. For the roundworm a review of the literature shows that nearly 300 substances have been used.

In spite of all these (sometimes dangerous) methods, it is a fairly simple matter to rid a patient of these worms without danger to himself. Sometimes it requires some patience and often repetition of treatment.

The word “parasite” in its original meaning meant “to eat beside” and referred to the retainers of the household who sat at the same table with the chief and the chief’s family. It was at first an honorable rather than derogatory term.

The roundworm, like nearly all parasites, has a remarkable natural history. The eggs are cast out on the ground either by human beings or animals and in communities where children go barefoot they may work their way through the skin of the feet (just as in the case of hookworm) or be swallowed with dirt and dirty particles of food. When the eggs enter the intestine they begin to develop and one would think that the normal process would be for the worm to form at that time, but instead of that a complicated set of changes takes place.

The embryos develop from the eggs and penetrate into the blood vessels and lymph vessels around the intestine, are carried to the right side of the heart, and from there to the lungs. Here they develop into small worms and pass up the windpipe and are again swallowed, at which time they develop into the adult worm. When mature they are between 8 and 14 inches in length.

They are not blood suckers, as is the hookworm, and seldom cause any nutritional disturbance, although they grow in such numbers as to cause intestinal obstruction.

Methods of treatment include the use of wormseed, or chenopodium. The dose depends upon the age and size of the patient. Chenopodium is sometimes poisonous and a better and more recent drug is hexylresorcinol, which is very effective against the worm, and practically non-toxic for man.