tag:blogger.com,1999:blog-629132641307534690.post7397105399925327898..comments2024-03-26T16:04:11.096-05:00Comments on Creepy Dreadful Wonderful Parasites: Answer to Case 131ParasiteGalhttp://www.blogger.com/profile/09093150363550239544noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-629132641307534690.post-52357819845367745372010-10-12T17:04:20.818-05:002010-10-12T17:04:20.818-05:00Thanks Salbrent. That's a very good point. T...Thanks Salbrent. That's a very good point. There are also some studies out there that show that E. dispar will rarely ingest RBCs, (albiet much less readily than E. histolytica). Here's one such article: <br /><br />Boettner et al. Entamoeba histolytica and Entamoeba dispar Utilize Externalized Phosphatidylserine for Recognition and Phagocytosis. Infection and Immunity 2005.<br /><br />of ErythrocytesParasiteGalhttps://www.blogger.com/profile/09093150363550239544noreply@blogger.comtag:blogger.com,1999:blog-629132641307534690.post-37955822377521961642010-10-12T12:32:11.046-05:002010-10-12T12:32:11.046-05:00Ferric Fang, MD said earlier
the once saw a patien...Ferric Fang, MD said earlier<br />the once saw a patient with RBC-containing E. dispar in his stool who turned out to have inflammatory bowel disease on biopsy; the gastrointestinal bleeding caused by the inflammation provided RBCs for ingestion by the non-pathogenic amoebae. E. histolytica was excluded by a negative serology, negative ELISA for the GAL/GALNAc-specific lectin of E. histolytica, and colonoscopy <br />with biopsy which showed no evidence of amebic colitis. In their review of the laboratory diagnosis of amebiasis (Clin Microbiol Rev <br />16:713-29, 2003), Tanyuksel & Petri observe that "A poor man's way to distinguish E. dispar from E. histolytic microscopically is erythrophagocytosis. . . However in some cases E. dispar is also observed to contain RBCs." ("Poor man's" is not meant pejoratively here, just to designate settings in which more definitive methods are unavailable).Salbrenthttps://www.blogger.com/profile/16888885622183700759noreply@blogger.comtag:blogger.com,1999:blog-629132641307534690.post-5859291412342557642010-09-28T20:04:02.396-05:002010-09-28T20:04:02.396-05:00Neuro_nurse raises an excellent point. Both of th...Neuro_nurse raises an excellent point. Both of the statements listed above are true. <br />"Approximately 90% of the asymptomatic intestinal infections previously attributed to E. histolytica were actually due to E. dispar" (or E. moshkovskii). In addition, we also know that of PCR-proven E. histolytica infections, approximately 90% are asymptomatic. So that means that E. histolytica infection is much less common than previously thought (especially in countries such as the US where almost all infections were actually due to E. dispar), AND that invasive infection by PCR-proven E. histolytica is actually a rare occurrence. I hope this clarifies any confusion. Thanks for the question!ParasiteGalhttps://www.blogger.com/profile/09093150363550239544noreply@blogger.comtag:blogger.com,1999:blog-629132641307534690.post-69600123912671383972010-09-28T12:11:39.102-05:002010-09-28T12:11:39.102-05:00I don't doubt that there are asymptomatic E. h...I don't doubt that there are asymptomatic <i>E. histolytica</i> infections, but I wonder about the prevalence of asymptomatic <i>E. histolytica</i> versus the prevalence of <i>E. dispar</i>.<br /><br />"<i>Approximately 90% of the asymptomatic intestinal infections previously attributed to infection with E. histolytica were actually due to E. dispar.</i>" <br />Long: Principles and Practice of Pediatric Infectious Diseases, 3rd ed.<br /><br />"<i>All E. moshkovskii and E. dispar infections and as many as 80% of E. histolytica infections are asymptomatic.</i>"<br />Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 7th ed.<br /><br />Those two statements do not necessarily contradict each other.neuro_nursenoreply@blogger.com