"Endolimax nana is a relatively new member of the pathogenic group of amoebas. It is the smallest of the intestinal amoebas, causing researchers of the past to overlook its potential virulence. This amoeba lives in the lower bowel, but the larvae can sluggishly travel to other parts of the body. It has been linked as a possible cause of Rheumatoid Arthritis , as well as a host of other collagen-related diseases. (See The Causation of Rheumatoid Disease and Many Human Cancers: A New Concept in Medicine, by Roger Wyburn-Mason, MD, PhD). Typically, other researchers disagree and are looking for another cause."

http://www.innvista.com/health/microbes/protozoa/amoebas.htm



"A symmetrical polyarthritis with low titer positive rheumatoid factor occurred in a young man who also complained of chronic diarrhea after returning from Vietnam. Endolimax nana grew on stool culture. Both the patient's diarrhea and Arthritis responded effectively to therapy with metronidazole. The diagnosis of parasitic rheumatism was made in retrospect. Diagnostic consideration should be given to this entity in patients with unusual arthropathies, particularly if they have stayed in an endemic parasitic country and have gastrointestinal symptoms."

http://www.ncbi.nlm.nih.gov/pubmed/6604161


The association of Blastocystis hominis and Endolimax nana with diarrheal stools in Zambian school-age children

http://www.springerlink.com/content/7544x464kwt2g65n/


CDC list endolimax nana as non-pathogen

http://www.cdc.gov/parasites/nonpathprotozoa/



I talked with a infection specialist that told labratories often overlooked endolimax nana and that many doctors considered it non-pathogen, he claimed it likely was pathogen. That it possibly can be pathogen seems to be supported by several research papers.