CISRA’s Synergy Health Newsletter

Issue 6. A Highly Sensitive Saliva Test for the Common Parasite, Entamoeba histolytica (2000)

by J. C. Waterhouse, Ph.D.

For years I had suspected that a parasite might be contributing to my irritable bowel syndrome, but repeated and extensive parasite tests over the years failed to detect any parasite (I had several stool tests, even including something called a stool purge test that was supposed to be especially sensitive). Then I heard about Diagnos-Techs Lab’s combination of tests that included a saliva test for the parasitic amoeba, Entamoeba histolytica. The test showed that I had antibodies to Entamoeba histolytica in my saliva, indicating an infection of the mucosal lining of the gastrointestinal tract. After this test, I had 4 weeks of treatment with a combination of antibiotics (in my case, tinidazole and tetracycline; others such as metronidazole and iodoquinone might be used instead and may be more easily obtained than tinidazole). Two antibiotics are usually needed to be sure to eradicate the amoeba, and to destroy the amoebic cysts as well. Although some recommend only 10-20 days of treatment, others recommend 30 days of treatment. Since relapses are not uncommon, I believe the longer treatment duration may be preferable. I believe treatment made a significant difference in my intestinal symptoms. If your doctor requests it, Diagnos-Techs lab will provide a recommended treatment protocol that they find to generally be effective in completely eradicating the parasite.

A follow-up test a few months later can be used to verify the success of therapy. Waiting a few months for the follow-up test allows the levels of the antibodies in the saliva that indicate an infection to decline following eradication of the parasite. If the antibodies are still present in the saliva, it means the parasite has not been eradicated from the mucosal lining. In chronic cases where the patient has been weakened by illness, it may be more difficult to eradicate, thus making the follow-up test after treatment especially important to consider. Currently, Diagnos-Techs offers a gastrointestinal health panel, which combines a number of types of tests, including screening for pathogens (bacteria, fungi, yeast and various parasites), enzymes to assess digestive health, an immune marker for gluten intolerance, and markers to detect irritation, inflammation and overall status and integrity of the gut. They find that with the proper indications and information, this panel of tests is usually covered by insurance companies and Medicare (HMOs and Medicaid may not cover it, however). For more information on all their tests and their use of saliva tests, contact the lab at 800-87-TESTS or go to their web site at (also see pages 13-14, later in this issue, for a discussion of some of their other tests). Diagnos-Techs Lab is CLI & COLA accredited and uses parameters that have been standardized by the World Health Organization.

To provide a little more background on Entamoeba histolytica, I looked it up in medical textbooks (Fauci, and others, editors, 1997, Harrison’s Principles of Internal Medicine. McGraw-Hill and Grendell, 1997, Current Diagnosis and Treatment in Gastroenterolog, McGraw-Hill Professional Publishing). Infection with this pathogenic amoeba around the world is quite common, occurring in 10% of the population worldwide. It is usually acquired by eating or drinking fecally-contaminated water and may be acquired while traveling in areas of the world with poorer sanitation. It can exist in a cyst form that is fairly resistant to stomach acid and chlorine. It is a cause of traveler’s diarrhea in less than 3% of cases, however it may not cause symptoms until a week, or as long as a year later. It also may be acquired in various institutional settings, like nursing homes, or child care centers where there are people who originate from or have traveled to other countries. One study showed an infection rate as high as 31.7% among male homosexuals (Kean et al. 1979. Br. J. Vener. Dis. 55:375 as cited in Diagnos-Techs Manual, 1994).

Although most people who harbor the parasite remain asymptomatic, it can cause levels of illness ranging from mild to severe. It can cause malaise, anorexia, bloody stools and ulcers in the colon, and it may even be mistaken for inflammatory bowel disease. In some cases, the parasitic amoeba also may invade the bloodstream and can cause serious infections in various organs in the body, particularly in the liver, where abscesses may form, which may be especially dangerous if they rupture. The parasite may even occasionally infect the lungs, brain, genitals and other organs. In its milder symptomatic form it may cause chronic, but intermittent diarrhea, with or without bloody stools or weight loss.

Despite the serious illness it may cause in some people, it is estimated that 90% of the people who carry this amoeba are completely without symptoms. Thus, one may unknowingly be exposed to it by someone who is an asymptomatic carrier. So, even if you haven’t traveled to another country, if you have been living with someone who has, or have been served by a restaurant worker who has, you may still acquire it. Due to the potential dangers of this parasite it is generally recommended that even asymptomatic patients be treated to protect the infected person and their contacts. One person’s immune system may be strong enough to keep it in check or eliminate it, but one of their contacts may be more vulnerable, due to stress, debility or irritation or inflammation of the gastrointestinal system.

If you do test positive, it may be advisable to have close contacts tested as well. Two of my close contacts were tested following my testing positive using the saliva test for the amoeba. It may not be a coincidence that the contact who also tested positive had been given radiation treatments for prostate cancer and had a radiation-damaged bowel, which may have made him more vulnerable to the infection. His intermittent diarrhea, which sometimes seemed to be initiated by an intestinal flu, but lasted for weeks, was completely gone after antibiotic treatment for the amoeba. The intermittent diarrhea did not recur in following years. Several months after treatment, his saliva was retested and found to be negative for the antibody to the amoeba, indicating that Entamoeba histolytica was completely eradicated.

Although the use of this saliva test is not very widespread yet in this country, experience has indicated that it can be useful in cases where the amoeba has invaded the mucosal lining of the gastrointestinal tract and provoked antibody production (specific secretory IgA), yet is not actively being shed into the stool. In the more extreme cases, with severe diarrhea, the amoeba may be detected in the stool more easily than in intermittent, milder cases. The saliva test for antibodies to the amoeba is not commonly used by most labs, who rely primarily on stool samples or antibodies in the blood. Antibodies in the blood are only found in the minority of cases where the amoeba has invaded the blood stream, thus they are not helpful for diagnosis if the amoeba is only in the mucosal lining, as is most frequently the case.

With increasing amounts of travel and immigration making exposures to parasites all the more frequent, I conclude that almost anyone with chronic gastrointestinal problems, particularly intermittent diarrhea, might find it worthwhile to discuss this parasite test with their physician. Your doctor may decide to first do a standard stool test for ova and parasites with a local laboratory, which may well be negative. However, if it is negative, I don’t think that should necessarily discourage you from proceeding to the saliva test, since it may be hard to detect the amoeba in the stool (as it was in my case). If your doctor is unaware of the saliva test and the other tests in the gastrointestinal panel and does not want to order them, Diagnos-Techs Lab (800-87-TESTS) will probably be able to help you locate a doctor who is more familiar with the use of these tests. When combined with the other markers in Diagnos-Techs gastrointestinal panel, which might detect other problems as well, like gluten intolerance (one has to have been eating gluten-containing grains fairly recently for maximum sensitivity of the test), or other pathogens, like Giardea lamblia, the results may prove quite useful. An extended gastrointestinal panel is also available, which detects intolerances to several common foods, as well.

Editorial Note (2006): I was not helped much by treatment for Entamoeba histolytica, though other may be. For my current views on the best approach to fibromyalgia and and many other chronic illnesses, see the transcript of a talk I gave before a Support Group in 2005. I give an overview of what has helped me most, with an emphasis on a new approach, called the Marshall Protocol (MP). For more information, see and other articles on this site.

Editorial Note (2008): I had much greater success with the Marshall Protocol than previous treatments, see: ( and I now consider the evidence to be very strong that hard-to-detect bacterial pathogens are responsible for fibromyalgia and many other chronic inflammatory and autoimmune diseases ( It appears that the general improvement of the immune system’s functioning on the Marshall Protocol tends to help combat viral, fungal and parasitic and their individual treatment may prove unnecessary.

Disclaimer: All articles provided on the SynergyHN website are for information only and are not intended as medical advice. An effort is made to be accurate, however readers are advised to verify what is presented here and check with their own doctors. No guarantee of accuracy is expressed or implied. Neither CISRA nor the author receives any funding or income from any organization or manufacturer connected with the topics discussed.

Written by synergyhn

October 30, 2008 at 12:32 am

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