The Animal Kingdom a Reservoir of Disease-Part 3

Greetings! In this week’s class we will learn about parasites common to animals and man. There is a parasite that “may lodge in the heart, brain, or eye and cause serious consequences” Find out what this is, in today’s class.

Parasites Common To Animals And Man


‘Man probably owes most if not all of the parasites that he may harbor to his long and intimate association with animals. Comparatively few intestinal worms or other parasites live exclusively as adults in or on human beings. Among the worm parasites (helminths), only seven that are more or less widespread and important are said to be confined to human beings. Two of these are acquired by man from the flesh of domestic animals used for food. The other five are transmitted from one human being to another directly or through the agency of invertebrate animals acting as carriers (vectors) for the worms in their infective stages.

‘Included in the group of adult helminths common to animals and man are a small number of species that are frequently found in human beings. It is believed, however, that some of them are rarely or never transmitted from animals to man and that despite the identical appearance  of worms of these species from human and animal hosts, those found in man are distant biological strains or varieties. Man is merely an occasional host of adult worms of many species usually found in dogs, cats, swine, sheep, cattle, and other animals; and he may become parasitized by the larval stages of certain worms that occur as adults in some of these animals. Such infestations are traceable to divert or indirect association and contact with the normal hosts or the invertebrate carriers of the parasites.

‘Some of the parasites transmissible from domestic and wild animals to man act as carriers for virus and bacterial diseases, and others directly and seriously affect his health, sometimes causing death. Many kinds of parasites do not produce well-defined, acute symptoms following a more or less regular course, as do bacterial and virus infections, and the injury caused by parasites usually depends on the number present.

‘By no means all the parasites transmissible from animals to man, or even from domestic animals to man, are included in this article, but most of the important ones and most of those reported as having been found in human beings in the United States are mentioned or briefly discussed.’


‘So far as is known, man does not acquire any protozoan parasites by eating the flesh of meat animals. Some of the protozoans that live in domestic animals are apparently transmissible to human beings, infection following ingestion for the infectious stages passed with the feces of animals. Thus Blantidium coli, a Colgate (having hairlike organs for locomotion) occuring in the intestines of man and sometimes causing a type of dysentery, is also found in pigs, and these animals are thought to serve as reservoirs of infection. Though some authorities deny the probability, others have considered it likely that cats and rodents serve as reservoirs and disseminators of infections with Giardia, a flagellate (having whiplike organs for locomotion) that occurs in man’s intestines and sometimes causes a recurrent diarrhea and other disturbances.

‘Some investigators believe it probable that pigs, rats, and especially monkeys act as reservoir hosts for Entamoeba histolytic, which causes amoebic dysentery and is one of man’s most important intestinal protozoans. Wild and domestic animals are suspected of being reservoir hosts for certain of the trypanosomes that cause disease in man. The type of sleeping sickness caused by trypanosomes, which is widespread in Africa, is transmitted by insects and ranks as one of the most important disease of man…’Perhaps the most important protozoan disease of man in this country is malaria.’

Worm Parasites

‘The roundworm, or nematode, Trichinella spiralis, is undoubtedly the most important worm parasite transmissible from domestic animals to man. This worm causes trichinosis.

‘Two other worm parasites that man acquires by eating infected meat, either raw or imperfectly cooked, or improperly processed meat products are the beef tapeworm and the pork tapeworm. The adults live in the small intestine of man, and the eggs or segments containing eggs pass out with the feces. Cattle or swine that swallow the eggs of the respective tapeworms become infested with the larval stages, known as bladder worms, which become localized in the muscles of these intermediate hosts. When a human being swallows the live bladder worms in meat, he becomes infected with the adult worms. Man can also serve as an intermediate host of both tapeworms, and if a person swallows their eggs as a result of unsanitary conditions he becomes infected with the bladder worm stages. The pork tapeworm is the more dangerous to man in this respect, since the bladder worms may lodge in the heart, brain, or eye and cause serious consequences.’

Quote to Note:

“Don’t become scavengers. The pig is a scavenger. God made them so. They pick up everything—every dirty thing. God does not want you to be that way.” Ms 163, 1898

Flesh was never the best food; but its use is now doubly objectionable, since disease in animals is so rapidly increasing. Those who use flesh foods little know what they are eating. Often if they could see the animals when living and know the quality of the meat they eat, they would turn from it with loathing. People are continually eating flesh that is filled with tuberculous and cancerous germs. Tuberculosis, cancer, and other fatal diseases are thus communicated. The tissues of the swine swarm with parasites. Of the swine God said, “It is unclean unto you: ye shall not eat of their flesh, nor touch their dead carcass.Deuteronomy 14:8.’ MH 313


Grab a friend and share the wealth, from what you’ve learned in the School of Health! In next week’s class we shall learn about bacterial infections and parasites common to man and animals. Until then, God bless!

Previous Lesson: Part 1, Part 2

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