Entamoeba histolytica is the responsible parasite of amoebiasis and remains one of the top three parasitic causes of mortality worldwide. Entamoeba histolytica an overview sciencedirect topics. Others such as entamoeba coli not to be confused with escherichia coli and entamoeba dispar are harmless. In a small percentage of infections, the trophozoites become invasive and.
Some important species of entamoeba are described below. Entamoeba histolytica, a protozoan parasite, is the etiologic agent of amoebiasis in humans. According to the best estimates walsh 1986 approximately 48 million individuals suffer from amoebiasis throughout the world. Seven species of amoeba are natural parasites of man. This species occurs in the cecum and colon of the domestic rabbit. In 1984, at least 40,000 deaths were attributed to amoebiasis. The genus entamoeba was established by leidy in 1879. Mature cysts typically have 8 nuclei but may have as many as 16 or more. Entamoeba histolytica is the pathogen responsible for invasive amoebiasis which includes amoebic dysentery and amoebic liver abscesses. Entamoeba histolytica is an invasive, pathogenic protozoan, causing amoebiasis, and an important cause of diarrhea in developing countries. With the exception of entamoeba gingivalis, which lives in the mouth, and e. Diagnosis of amebic dysentery by detection of entamoeba. Of these entamoeba histolytica is the only species found to be associated with intestinal disease. Comparison of enzymelinked immunosorbent assaybased kits and pcr amplification of rrna genes for simultaneous detection of entamoeba histolytica and entamoeba dispar.
A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Both organisms contain a central nucleus with a prominent karyosome. Peripheral chromatin is fine, uniform, and evenly distributed. In the intestine, cysts undergo excystation, and the intestinal stage, known as a trophozoite, is released and begins to multiply asexually. Multiple stool samples at least 3 should be tested before a negative result is reported. Predominantly infecting humans and other primates causing amoebiasis, e. Losch 1875 first described entamoeba histolytica as amoeba coli. Entamoeba coli introduction entamoeba coli is a nonpathogenic amoeba with world wide distribution. Pdf the present study was conducted to investigate the clinical outcomes of entamoeba histolytica infection in symptomatic and asymptomatic orang asli. Dixon, in foodborne parasites in the food supply web, 2015. The infection is acquired by ingestion of cysts in fecally contaminated food or. Amebiasis is an infection by the protozoan parasite, entamoeba histolytica. Hostparasite interactions in entamoeba histolytica and. A mature cyst has 4 nuclei while an immature cyst may contain only 1 to 3 nuclei.
Entamoeba coli is a nonpathogenic species of entamoeba that frequently exists as a commensal parasite in the human gastrointestinal tract. An invasive strainspecific monoclonal antibody against entamoeba histolytica has been used in a capture enzymelinked immunosorbent assay elisa for the detection of invasive e. Entamoeba histolytica antibody, serum sam clinical. Entamoeba histolytica a number of outbreaks have resulted from a breakdown in sanitation or behavioral practices of people. Loschs organism was renamed entamoeba histolytica by fritz schaudinn in 1903. Entamoeba histolytica introduction there is a large number of species of amoebae which parasitise the human intestinal tract. Chalmers, in microbiology of waterborne diseases second edition, 2014. Ausbruche werden im anschluss an katastrophen verzeichnet, wenn nur ungenugend reines trinkwasser zur verfugung steht.
Entamoeba definition of entamoeba by medical dictionary. Nov 15, 20 entamoeba histolytica distribution parasite has worldwide distribution but is most common in the tropical and subtropical areas of the world. The genus entamoeba phylum sarcodina, order amoebida, family endamoebidae is one of the many amoebae that inhabit the human gastrointestinal tract, including dientamoeba fragilis, entamoeba histolytica, entamoeba coli, entamoeba dispar, entamoeba gingivalis, entamoeba hartmanni, entamoeba moshkovskii, entamoeba polecki, chilomastix mesnili, endolimax nana, and iodamoeba butschlii. Entamoeba herbal treatment, prevention, symptoms, causes. Differential detection of entamoeba histolytica, entamoeba. With increased travel and emigration to developed countries, infection is becoming more common in nonendemic areas. It may cause amoebic dysentery and colonic ulcerations. Entamoeba histolytica distribution parasite has worldwide distribution but is most common in the tropical and subtropical areas of the world. In most infected individuals the trophozoites exist as commensals. In the expert meeting in mexico of 1997 the definition of.
Recently, the biochemical, immunological and genetic differences between entamoeba histolytica and entamoeba dispar, previously known as pathogenic and non. Differentiation of this organism from either entamoeba histolytica e. The cysts are distinguished by noticing the eight nuclei found in the mature form. A singleround pcr assay was developed for detection and differential diagnosis of the three entamoeba species found in humans, entamoeba moshkovskii, entamoeba histolytica, and entamoeba dispar, that are morphologically identical as both cysts and trophozoites. Entamoeba histolytica and entamoeba dispar basic guidelines a. Entamoeba is a single celled parasite that causes digestive tract infection. A conserved forward primer was derived from the middle of the smallsubunit rrna gene, and reverse primers were.
Our understanding of its epidemiology has dramatically changed since this amoeba was distinguished from another morphologically similar one, entamoeba dispar, a non pathogenic and commensal parasite. Although the majority of individuals infected with e. Escherichia coli mediated resistance of entamoeba histolytica to oxidative. Mar 21, 2011 differential virulence between entamoeba species and strains. Pdf different clinical outcomes of entamoeba histolytica in. Entamoeba coli y histolytica especialidades medicas. Entamoeba polecki, entamoeba coli and entamoeba hartmanni reside in the. Entamoeba coli is a nonpathogenic amoeba protozoa with world wide distribution.
Previously, it was thought that 10% of the world population was infected, but these. Escherichia coli mediated resistance of entamoeba histolytica to. Introduction the protozoan parasite, entamoeba histolytica, is the causative agent of amoebiasis in humans. Laboratory diagnostic techniques for entamoeba species ncbi. Entamoeba coli what are the similarities between e. Entamoeba coli o agente causador da amebase comensal no patognica. Both contain storage food granules in the cytoplasm.
Entamoeba coli is the only entamoeba species found in humans that has more than four nuclei in the cyst stage. The parasite escapes from the digestive tract and enter the blood stream. The genus entamoeba was defined by casagrandi and barbagallo for the species entamoeba coli, which is known to be a commensal organism. Entamoeba histolytica pathogenic protozoan of the large. In this article we will discuss about entamoeba histolytica.
Multiplex pcr can differentiate the pathogenic amoebae. To maximize recovery of cysts, stool samples in formalin, or other fixatives, should be concentrated prior to microscopic examination e. Entamoeba histolytica is the causative agent of amebiasis and is considered a. Fritz schaudinn 1903 established the differentiation between entamoeba histolytica and endamoeba coli, schaudinn decided to call it e. Entamoeba histolytica is a unicellular parasite which infects millions of humans. Entamoeba histolytica is a parasitic amoeba belonging to the phylum sarcomastigophora, which has an environmentally resistant infectious stage, known as a cyst.
Pathogenesis of infection by entamoeba histolytica springerlink. Cysts of entamoeba coli are usually spherical but may be elongated and measure 1035 m. Although many people harbour this organism world wide, only about 10% develop clinically. Entamoeba histolytica is an amoeba with worldwide distribution, transmitted through the fecaloral route sakakibara et al. Difference between entamoeba histolytica and entamoeba coli. Entamoeba is a disease of the gastrointestinal tract. Entamoeba histolytica cause dangerous syndrome called amoebiasis amoebosis. Entamoeba histolytica was first reported by losch 1875 in russia, but he described it as amoeba coli. Colonization with the morphologically identical parasite e. Geographical distribution of entamoeba histolytica 3. It exists in two formsthe trophozoite which is the active, dividing form, and the cyst which is dormant and can survive for prolonged periods outside the host. Entamoeba histolytica is an anaerobic parasitic amoebozoan, part of the genus entamoeba. Feb 27, 2018 dental assisting training video for dental office staff.