Yes, I know what you mean. If you're interested in reading some firsthand account/horror stories go to http://www.badbugs.org/. This website has alot of information about blastocystis hominis and dientamoeba fragilis, both protozoal infections. Some of these people suffered for 20 years, because the medical establishment refused to recognize these organisms as pathogenic. I know that only in the last 2 years the U.S. officially changed their view that blasto. hominis can be a disease causing organism. Also according to her website in one study 40% of the people diagnosed with Irritable Bowel Syndrome tested positive for blastocystis hominis. Even if the doctor tests for parasites, the labs do not use the specialized techniques required to properly diagnose these 2 parasites, although these 2 parasites are way more common than either giardiah or amoebas. According to her website, when diagnosing someone with IBS , many doctors do not routinely test patients for parasites at all. Apparently many western doctors do not believe parasitic infection is a problem for their patients, unless they've recently visited a third world country. This is quite ironic when you consider that the original reason they refused to recognize b. hominis or dientamoeba fragilis as pathogenic organisms, is that they were so very common in the stool samples of people who had no symptoms. In my opinion, to diagnose patients with IBS without parasite testing, when symptoms of the 2 diseases are virtually identical, flies in the face of any logical thinking.
I also read on different websites, that many people were diagnosed "negative" when there were worms directly observed by the patients in the stool sample. Regarding the treatment of parasites, I found a very cheap and effective treatment for worms at http://www.freshwaterorganics.com./. It was posted on this forum a few days ago.