More than two billion people worldwide suffer unnecessary parasitic infections. As far as can be determined, Americans play host to more than 130 different kinds of parasites, ranging from microscopic organisms to sizeable tapeworms. Projections for the year 2025 suggest that more than half of the 8.3 billion people on earth at that time will be infected with at least one parasitic disease. The CDC estimates that there are fifty million cases of food-borne illnesses alone, with thousands dying as a result. Some parasites can remain in the body for more than thirty years. This was proven when WWII POW’s were examined thirty years later. It was found that 15% were still infected with strongyloides acquired during that war. More recently, when more than 500,000 American troops returned from Desert Storm, they were told not to donate blood because they had been exposed to Leishmania. Without question, thousands of Viet Nam vets are still suffering from undiagnosed parasitic infections.
Medical parasitology includes study of parasites from four large phyla in the animal kingdom, namely, Protozoa (of the kingdom Protista), the Platyhelminthes (flatworms), the Nematodes (roundworms), and the Arthropoda (arachnids, crustaceans, insects, etc.). The worms and arthropods are multicellular organisms and often large enough to be seen with the naked eye. Some, like the tapeworms, may obtain lengths of several meters. Parasites, that live outside the body of a host are called Ectoparasites, which include fleas, mites, lice, ticks and leeches. Endoparasites live inside the body of a host, and include amoebas, worms, and flukes.
Parasites are organisms which live in or on another living organism called a ‘host,’ benefiting in some way at the host’s expense, particularly in their plunder of nutrients. A host will suffer some degree of damage, ranging from slight discomfort to death. Most people are not aware that they have parasites until an autopsy is performed. Others are more severely infected, causing disease. It is also a common belief that intestinal worms are more active during the full moon cycle. With a little knowledge, parasitic infestations can be controlled.
Another grave concern is that the majority of western doctors have never seen a parasite infection, nor are they taught to do so. Since parasitology courses center around tropical diseases, it gives the appearance that parasitic infections happens only in foreign countries. Even if identified, only a few physicians know what the treatment should be, and then only with toxic pharmaceuticals. Another downside is that antiparasitic drugs are not sweeping, but will only kill one or two different types. In addition, if the correct medication in the correct dosage is not taken, it can cause the parasite to move from one organ of the body to another in its effort to avoid the medication. This movement will cause more problems than before, with parasites boring into other tissues and organs. In the case of tapeworms, if the therapy used does not remove the entire worm, and the head is left intact, the whole worm will grow back again.
The same holds true for diagnostic laboratories. There are over 1,000 species of parasites that can infect humans, but only forty or fifty tests are available to detect them. Some parasites do not reach the stool and are difficult to detect otherwise. It often takes multiple stool specimens (sometimes as many as twelve) as one often gives no indication of an infestation.
Limiting the idea that disease-causing parasites are found only in far away lands is dangerously idealistic. Widespread travel, immigration, pollution, increased use of day cares and other institutional settings, returning troops, increased popularity of household pets, the indiscriminate use of antibiotics and other immunosuppressive drugs, multiple sex partners with expanding anal/oral practices, and a general rise in population has seen to it that almost all people can now expect to be faced with the possibility of harboring at least one parasite at some point in their lives. Therefore, with the medical profession lagging behind in the awareness that millions of their own citizens are suffering, it is in the best interest of all to find out what can be done should such an occurrence happen closer to home.
Parasites vary significantly, both in size and method of infection. Even though most do not cause any significant harm, others can burrow into or dissolve away tissues of the cornea, spinal cord, muscles, heart, kidneys, bone, and brain. The size and weight of parasitic cysts produces pressure effects on these organs and their surrounding tissue. Parasites are much more complex than viruses or bacteria because their individual reproductive cycle makes it difficult to formulate an accurate diagnosis common to many complaints. Parasites can cause fever, intestinal pain, poor absorption of nutrients, and many other symptoms, resulting in misdiagnosed conditions of bacterial infections and treatment with antibiotics. This only serves to tighten the parasite’s grip.
Humans become hosts to parasites in several ways:
- Via infected food or water (sources of roundworm, amoebas, and giardia). Contact with water can be internal (tap water, mountain streams, contaminated bottled water etc.) or external (hot tubs, saunas, swimming pools, or other water recreational areas). Not only are parasites contracted in this manner, but also bacteria, viruses, and fungi. Chlorine does not rid a water supply of many pathogens. Protozoa, fungi, viruses, and coliform bacteria have been found alive and flourishing in chlorinated tap water, as well as in swimming water. In addition, unless specified, most filtering systems are unable to prevent Giardia lamblia and Cryptosporidium from passing on through.
- Via such vectors as a mosquito (carriers of dog heartworm, filaria, and malaria), fleas (carriers of dog tapeworm), houseflies (carriers of amebic cysts), and the sandfly (carriers of leishmaniasis). Close contact with animals, whether in the home or not, significantly increases the likelihood of parasite infections, especially children. When both the animal and the human receive treatment, the problem is generally solved, but if only one receives treatment, the problem becomes chronic.
- Via sexual contact with partners transmitting trichomonas, giardia, and amoebas, to name a few.
- Via the nose and skin. Pinworm eggs and Toxoplasma gondii can be inhaled from contaminated dust; hookworms, schistosomes, and strongyloides can penetrate exposed skin, especially bare feet.
- The airplane is considered another important pathway or vector, carrying parasites around the world at a much more rapid rate than ever before.
Less common parasites include Cyclospora cayetanensis, which is now being found in human feces, causing the disease cyclosporiasis. It first appeared after 1,000 people became ill after eating infected raspberries from Guatemala, where human waste had been used as fertilizer. Symptoms include the following: diarrhea, cramps, headaches, weight loss, decreased appetite, vomiting, fatigue, flatulence, bloating, itching skin, fever, and muscle aches. It can also cause such chronic conditions as malabsorption, anorexia, depression, and fibromyalgia. However, some have no symptoms at all and are unaware they ae carrying the parasite and passing it on.
Another less common parasite is Dientamoeba fragilis, found increasingly in the large intestine of humans. It is considered one of the most frequent parasitic infections of day care centers and crowded urban areas. It does not have a cyst stage, but lives in the intestinal tract, the cecum, and the colon as a larvae or trophozoite, similar to an amoeba. This form makes it difficult to detect in lab samples. Transmission is by direct ingestion of the larvae, but it can also be found within the eggs of some worms, especially pinworms. Infection usually causes diarrhea and abdominal discomfort, with chronic infestation leading to autoimmune reactions.
