Entamoeba histolytica is a protozoan parasite that causes amebic dysentery and liver abscess. Entamoeba dispar, morphologically indistinguishable from e. Multiple stool samples at least 3 should be tested before a negative result is reported. Amebiasis chapter 4 2020 yellow book travelers health. Intestinal amebiasis is caused by the protozoan entamoeba histolytica. Laboratory methods of identification of entamoeba histolytica and its differentiation from lookalike entamoeba spp. Longterm travelers duration 6 months are significantly more likely than shortterm travelers duration histolytica infection. Entamoeba histolytica is not easily transmitted from animals to humans, due to the fact that this parasite rarely encysts in the.
Prevention and control of amoebic dysentery in hong kong. It infects predominantly humans and other primates it infects predominantly humans and other primates francais. Prevalence of entamoeba species in captive primates in. Infection by entamoeba histolytica occurs by ingestion of mature cysts 2 in fecally contaminated food, water, or hands. Recent immigrants and refugees from these areas are also at risk. Oti published understanding the epidemiology of entamoeba histolytica infections find, read and cite all the research you need on. Entamoeba histolytica has been found in all populations throughout the world where search has been conducted. Entamoeba histolytica amebiasis infectious disease and.
Currently, information on prevalence of this infection among different ethnic groups of orang asli is unavailable in malaysia. It contains four nuclei when mature, one nucleus when immature with glycogen in a. Prevalence of entamoeba histolyticaentamoeba dispar in the. Entamoeba histolytica and entamoeba dispar basic guidelines a. Recent findings prevalence of amoebiasis differs greatly. 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. Recent studies have revealed opportunities to produce an effective vaccine against the entamoeba histolytica infection. Entamoeba histolytica trophozoite islamic university of gaza. Introduction the protozoan parasite, entamoeba histolytica, is the causative agent of amoebiasis in humans.
Jun 10, 2011 entamoeba histolytica is an important protozoan intestinal infection in resourcepoor settings, including vietnam. Entamoeba polecki is an intestinal protozoan which is best known for its infection and never identified or were misdiagnosed as e. Life history of entamoeba histolytica parasitology. Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus entamoeba. Understanding the epidemiology, pathophysiology, and the molecular and genetic biology of the organism will not only lead to improved diagnostic and treatment options but, ultimately, to the development of a safe.
Entamoeba histolytica and another ameba, entamoeba dispar, which is about 10 times more common, look the same when seen under a microscope. Longterm travelers duration 6 months are significantly more likely than shortterm travelers duration nov 15, 20. The disease is common in tropical regions of the world where hygiene and sanitation is often approximate. Prevalence and characters of entamoeba histolytica infection in. In 1984, at least 40,000 deaths were attributed to amoebiasis. Overall prevalence of entamoeba histolytica was 11. Entamoeba histolytica is a unicellular, protozoon parasite of humans. Epidemiology amebiasis is responsible for around 100,000 deathsyear, mainly in central and south america, africa, and india, as well as for a. The epidemiology of entamoeba histolytica in a nigerian. View entamoeba histolytica research papers on academia. This kind of protozoan parasite resides in the mucous and submucous layer of the large intestine specially at the iliocaec. With the exception of entamoeba gingivalis, which lives in the mouth, and e. Of these entamoeba histolytica is the only species found to be associated with intestinal disease.
The laboratory diagnosis of human parasitic amoebae. In most infected individuals the trophozoites exist as commensals. Epidemiology surveillance system little is known of the epidemiology of amebiasis from e. Entamoeba histolytica an overview sciencedirect topics. The world health organization has recommended that e. Nuclear division occurs within the cyst, resulting in a quadrinucleated cyst, and the chromatoid bodies and glycogen vacuoles disappear. It is more prevalent in the tropics and subtropics than the cooler climates. Prevalence and risk factors associated with entamoeba. In this study, entamoeba histolytica had high prevalence and unusual. Worldwide, approximately 50 million people develop colitis or extraintestinal disease, with over 100,000 deaths annually.
Entamoeba histolytica, the causative agent of human amoebiasis remains a significant cause. Background entamoeba histolyticaentamoeba disparentamoeba moshkovskii infection is still prevalent in rural malaysia especially among orang asli communities. Entamoeba histolytica introduction there is a large number of species of amoebae which parasitise the human intestinal tract. The epidemiology of entamoeba histolytica in a nigerian urban. Infection with entamoeba histolytica has the potential to cause dysentery and extraintestinal disease, whereas e.
Entamoeba histolytica is the pathogen responsible for invasive amoebiasis which includes amoebic dysentery and amoebic liver abscesses. Infection by the parasite entamoeba histolytica causes amebic dysentery and amebic liver abscess, diseases associated with a high morbidity and mortality. Others such as entamoeba coli not to be confused with escherichia coli and entamoeba dispar are harmless. Amebiasis is distributed worldwide, particularly in the tropics, most commonly in areas of poor sanitation. Amoebiasis is an unsolved public health problem and an endemic disease in. Epidemiology of entamoeba histolytica worldwide distribution. There was a problem providing the content you requested. Amoebiasis or more correctly it should be called as amoebic dysentery is caused by a protozoan parasite known as entamoeba histolytica. Entamoeba histolytica neglected tropical diseases e3s web of. Ingestion of fecally contaminated food or water is the primary mode of transmission. Excystation 3 occurs in the small intestine and trophozoites 4 are released, which migrate to the large intestine. This kind of protozoan parasite resides in the mucous and submucous layer of the large intestine specially.
Entamoeba histolytica multiplies by binary fission in the trophozoite stage. Entamoeba histolytica, a protozoan parasite, is the etiologic agent of amoebiasis in humans. Molecular differentiation of entamoeba histolytica. It exists in two formsthe trophozoite which is the acti. It was not until 1993 that diamond and clark 1993 gave the ultimate redescription of e. Prevalence and risk factors associated with entamoeba histolytica. Epidemiology worldwide up to 50% of population in areas of poor sanitation or tropics in the united states 15%. The epidemiology of entamoeba histolytica in a nigerian urban population. A 9monthold boy with lesions on the abdomen died without treatmentthe diagnosis was obtained post mortem. Pathogenesis of infection by entamoeba histolytica springerlink. Entamoeba histolytica is a an anaerobic parasitic protozoan that is responsible for the development of amoebiasis. Pathogenesis of infection by entamoeba histolytica. Microscopic examination of multiple faeces samples of 2 825 persons was carried out in the metropolitan lagos. Entamoeba histolytica epidemiology a worldwide distribution.
Intestinal parasitic infection is still a common and significant public health problem among children in saudi arabia. Epidemiological studies carried out using culture or microscopy in most of the amoebiasis endemic developing countries, yielded confusing results since none of these could differentiate the pathogenic entamoeba histolytica from the nonpathogenic entamoeba dispar and entamoeba moshkovskii. Mild and moderate intestinal disease and invasive infection. Easy diagnosis of amoebiasis now depends on the use. Entamoeba histolytica entamoeba histolytica cysts are present only in the lumen of the colon the cyst may contain a glycogen vacuole and chromatoid bodies with characteristic rounded ends. The epidemiology of entamoeba histolytica in mexico city. Pdf understanding the epidemiology of entamoeba histolytica. To maximize recovery of cysts, stool samples in formalin, or other fixatives, should be concentrated prior to microscopic examination e. Life cycle cysts ingested by man reach the colon where reversion to trophozoites occurs and. Entamoeba histolyticaentamoeba disparentamoeba moshkovskii infection is still prevalent in rural malaysia especially among orang asli. Entamoeba histolytica is an invasive, pathogenic protozoan.
Unfavourable conditions in the habitat such as lack of nutrients, temperature deviations from the optimum range, decreased o 2 tensions, lowered ph and accumulation of metabolic wastes may be the causes for encystment. Pdf epidemiology of entamoeba infection in sudan researchgate. Amongthe260dotblot positive samples,monoinfections ofe. There is a clear need to perform epidemiological studies to find the true prevalence of entamoeba histolytica around the world. 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. Nov 15, 20 entamoeba histolytica distribution parasite has worldwide distribution but is most common in the tropical and subtropical areas of the world. May 01, 2020 entamoeba histolytica is a protozoan parasite that causes amoebiasis. Trophozoites of entamoeba histolytica live in the mucous and sub mucous layers of large intestine. Entamoeba histolytica is an anaerobic parasitic amoebozoan, part of the genus entamoeba. Pdf the epidemiology of entamoeba histolytica infection in sudan is poorly understood. In general it is estimated that approximately 90% of identified.
Review paper public health and clinical importance of. It moves by a jellylike tonguelike protrusion of the. The study objective was to assess risk factors of e. It infects an estimated 500 million people per year, causes liver abscess and colitis in 50 million, and results in death of an estimated 40,000100,000 individuals annually footnote 2 footnote 5. In a small percentage of infections, the trophozoites become invasive and. Our understanding of its epidemiology has dramatically changed since this amoeba was distinguished from another morphologically similar one, entamoeba dispar, a non. Therefore as far back as in 1925 a concept of the existence of two morphologically identical amoeba species was formulated brumpt 1925. Although many people harbour this organism world wide, only about 10% develop clinically. Entamoeba histolytica is an invasive, pathogenic protozoan, causing amoebiasis, and an important cause of diarrhea in developing countries. Entamoeba coli life cycle and location identical to. Research article open access entamoeba histolytica and. Entamoeba invadens is a species that can cause a disease similar to e. Pathogenesis and immune response toward entamoeba histolytica.
The purpose of this study was to assess the true prevalence of amoebiasis in selected north eastern states of india using dna based. Phylogenetic analysis of ribosomal rna gene sequences has demonstrated the monophyletic nature of the entamoeba genus silberman et al. A casecontrol study was conducted among residents of hanam province, northern vietnam. A higher prevalence in tropical and subtropical countries 10 % of the world population carries the parasite. To contribute to a better comprehension of the epidemiology of this infection, a crosssectional study aimed. Over the same period it has also become clear that the true incidence of e. The epidemiology of entamoeba histolytica has been complicated by the mid1990s redescription of e. Oyerinde jp, alonge aa, adegbitehollist af, ogunbi o. Author summary most epidemiologic studies in developing countries carried out for amoebiasis is either based on microscopy alone or culture microscopy used as a screening tool, have poor sensitivity and specificity and thus fails to figure out its true magnitude. Entamoeba spp free download as powerpoint presentation. Epidemiology worldwide up to 50% of population in areas of poor sanitation or tropics in the united states 15% certain areas high risk for. Risk factors for entamoeba histolytica infection in an. Similarly entamoeba moshkovskii, which was long considered to be a freeliving amoeba is also morphologically identical to e.
Further molecular studies have identified a third species, e. Entamoeba histolytica a number of outbreaks have resulted from a breakdown in sanitation or behavioral practices of people. This study aimed to determine the frequency of entamoeba histolytica and entamoeba dispar infection in school children in the community of tlaltizapan, in order to understand the dynamics of infection within the school and family spheres of this population. Recent findingsprevalence of amoebiasis differs greatly in different areas of the world reaching up to 50%. Entamoeba histolytica axenic growth improvement by ox bile. Extraintestinal manifestations include amebic liver abscess and other more. 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. Entamoeba histolytica, the causative agent of human amoebiasis remains a significant cause of morbidity and mortality in developing countries and is responsible for up to 100,000 deaths worldwide.
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