In 1984, at least 40,000 deaths were attributed to amoebiasis. Entamoeba histolytica is a pathogenic parasite in the intestine of human beings and many other primates. The epidemiology of entamoeba histolytica has been complicated by the mid1990s redescription of e. Overall prevalence of entamoeba histolytica was 11. Intestinal amebiasis is caused by the protozoan entamoeba histolytica. Clinical severity ranges from the asymptomatic passage of cysts in the stool to fulminant dysentery. Amoebiasis also causes colitis that can present with diarrhoea andor dysentery that can be acute or last more than 1 week. First molecular epidemiology of entamoeba histolytica, e. The epidemiology of entamoeba histolytica in a nigerian. Entamoeba histolytica was first discovered by losch in 1875 in leningrad, russia for causing disease in humans. With increased travel and emigration to developed countries, infection is becoming more common in nonendemic areas.
Multivariate analysis showed different sets of species. Pdf molecular epidemiology of amoebiasis in malaysia. In general it is estimated that approximately 90% of identified. Microscopic examination of multiple faeces samples of 2 825 persons was carried out in the metropolitan lagos. Entamoeba histolytica global water pathogen project. Recent studies have revealed opportunities to produce an effective vaccine against the entamoeba histolytica infection. Oti and others published understanding the epidemiology of entamoeba histolytica infections find, read and cite all the research. Entamoeba histolyticaentamoeba dispar trophozoites stained with trichrome entamoeba histolyticaentamoeba dispar trophozoites have a single nucleus, which have a centrally placed karyosome and uniformly distributed peripheral chromatin. Medical records, for 2000 and 2001, of symptomatic amoebic patients who were treated at our hospitals in tokyo, yokohama and osaka were studied retrospectively for the purpose of gathering epidemiological data on symptomatic entamoeba histolytica infection. Entamoeba histolytica and intestinal amoebiasis the. The highest prevalence of amebiasis is in developing countries where barriers between human feces and food. Molecular epidemiology of entamoeba spp evidence of a. Worldwide, approximately 50 million people develop colitis or extraintestinal disease, with over 100,000 deaths annually 3.
Hence, this study aimed to determine the prevalence of e. Amebiasis is caused by entamoeba histolytica see the image below, a protozoan that is found worldwide see etiology. Epidemiology and comparison of diagnostic methods in a setting of nonendemicity dylan r. Entamoeba histolytica amebiasis infectious disease and. Of these entamoeba histolytica is the only species found to be associated with intestinal disease. Pathogenesis of infection by entamoeba histolytica. Infection with entamoeba histolytica has the potential to cause dysentery and extraintestinal disease, whereas e. Predominantly infecting humans and other primates causing amoebiasis, e. Entamoeba moshkovskii perspectives of a new agent to be considered in the diagnosis of amebiasis. Entamoeba histolytica is microscopic and lives as an endoparasite in the upper part of the large intestine, i. Entamoeba histolytica is a protozoan parasite that causes amoebiasis.
A conserved forward primer was derived from the middle of the smallsubunit. Entamoeba histolytica, the causative agent of human amebiasis, remains a significant cause of morbidity and mortality in developing countries and is responsible for up to 100,000 deaths worldwide each year. Life cycle cysts ingested by man reach the colon where reversion to trophozoites occurs and. Prevalence of entamoeba histolytica and other enteral. To maximize recovery of cysts, stool samples in formalin, or other fixatives, should be concentrated prior to microscopic examination e. Anuar ts, almekhlafi hm, abdul ghani mk, abu bakar e, azreen sn, salleh fm, et al. Review articles diagnosis and epidemiology of amoebiasis in india. The prevalence of antibodies against entamoeba histolytica was studied in the mexican population using an immunoenzyme assay in solid phase elisa and semiautomatic equipment.
Understanding the epidemiology of entamoeba histolytica. Entamoeba histolytica is an invasive, pathogenic protozoan, causing amoebiasis, and an important cause of diarrhea in developing countries. The antigen was a mixture of membrane proteins obtained by triton x100 extraction from an axenic culture of entamoeba histolytica hm1imss. Kain 1 3 0 mcgill centre for tropical disease, montreal general hospital and mcgill university. Entamoeba coli life cycle and location identical to. Entamoeba histolytica an overview sciencedirect topics. Amebiasis, due to the pathogenic parasite entamoeba histolytica, is a leading cause of diarrhea globally. Oyerinde jp, alonge aa, adegbitehollist af, ogunbi o. Differential detection of entamoeba histolytica, entamoeba.
Entamoeba histolytica is an anaerobic intestinal amoeba parasite that predominantly affects a man and causes amoebic dysentery and liver abscess history. Amoebiasis is a common cause of diarrhoea in infants in lowincome countries. Chalmers, in microbiology of waterborne diseases second edition, 2014. It inhabits the mucous and submucous layers of the large intestine. In a small percentage of infections, the trophozoites become invasive and. Multiple stool samples at least 3 should be tested before a negative result is reported. This typical appearance of the nucleus is not always observed as some trophozoites can have nuclei with. Longterm travelers duration 6 months are significantly more likely than shortterm travelers duration entamoeba histolytica, is estimated to affect about 50 million people annually. About 10% develop invasive amoebiasis, which leads to 40 000110 000 deaths per annum. The epidemiology of infection with entamoeba histolytica in the. Although many people harbour this organism world wide, only about 10% develop clinically. According to the best estimates walsh 1986 approximately 48 million individuals suffer from amoebiasis throughout the world.
A countrywide stool survey of the gambia showed the prevalence of entamoeba histolytica cysts to range from. Pathogenesis of infection by entamoeba histolytica springerlink. Entamoeba dispar is morphologically identical but is not associated with disease. Abdominal tenderness and weight loss are common with amoebic colitis. Old methods used such as direct microscopy and culturing are insensitive compared to polymerase chain reaction pcr. Entamoeba histolytica and giardia lamblia are the most common protozoan pathogens of the human intestinal tract worldwide. Entamoeba histolytica epidemiology a worldwide distribution.
May 01, 2020 entamoeba histolytica is a protozoan parasite that causes amoebiasis. Entamoeba histolytica is an intestinal protozoan parasite and the causative agent of invasive amebiasis. Caused by the protozoan parasite entamoeba histolytica. It feeds mainly on the tissues of the intestinal wall and often produces severe ulcers and abscesses. Pathogenesis and immune response toward entamoeba histolytica. Entamoeba histolytica introduction there is a large number of species of amoebae which parasitise the human intestinal tract. Further molecular studies have identified a third species, e. Entamoeba histolytica and another ameba, entamoeba dispar, which is about 10 times more common, look the same when seen under a microscope. Amebiasis is an intestinal illness caused by a microscopic parasite called entamoeba histolytica who gets amebiasis. Prevalence of antibodies against entamoeba histolytica in.
Evaluation of entamoeba histolytica antigen and antibody point of care tests for the rapid diagnosis of amebiasis. Oti and others published understanding the epidemiology of entamoeba histolytica infections find, read and cite all the research you need on researchgate. Prevalence increased rapidly in younger age groups and there were no real differences between males and females. Recent immigrants and refugees from these areas are also at risk. Laboratory methods of identification of entamoeba histolytica and its differentiation from lookalike entamoeba spp. Entamoeba histolytica, a protozoan parasite, is the etiologic agent of amoebiasis in humans. Epidemiology of entamoeba histolytica in a nigerian urban. Entamoeba dispar, morphologically indistinguishable from e. Entamoeba histolytica a number of outbreaks have resulted from a breakdown in sanitation or behavioral practices of people. Transmission occurs via the faecaloral route, either directly by persontoperson contact or indirectly by eating or drinking faecally contaminated food or water. A higher prevalence in tropical and subtropical countries 10 % of the world population carries the parasite. 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.
The world health organization has recommended that e. Our understanding of its epidemiology has dramatically changed since this amoeba was distinguished from another morphologically similar one, entamoeba dispar, a non. Entamoeba histolytica and intestinal amoebiasis the nepali. Highlighting the different risk factors of entamoeba histolytica and entamoeba dispar infections among orang asli communities. Entamoeba histolytica causes amebic colitis and liver abscess in developing countries such as mexico and india. Longterm travelers duration 6 months are significantly more likely than shortterm travelers duration histolytica infection. To investigate the molecular epidemiology of entamoeba histolytica.
Epidemiology worldwide up to 50% of population in areas of poor sanitation or tropics in the united states 15% certain areas high risk for. Present characteristics of symptomatic entamoeba histolytica. Amebiasis is an intestinal illness caused by a microscopic parasite called entamoeba histolytica. 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 is the responsible parasite of amoebiasis and remains one of the top three parasitic causes of mortality worldwide. The disease is common in tropical regions of the world where hygiene and sanitation is often approximate. Although the majority of individuals infected with e. Potentially fatal extraintestinal amoebiasis, including amoebic liver abscess, complicates 1%3% of infections. Nov 22, 2019 entamoeba histolytica is an anaerobic intestinal amoeba parasite that predominantly affects a man and causes amoebic dysentery and liver abscess.
The gastrointestinal pathogen entamoeba histolytica causes amoebiasis. Anyone can get amebiasis, but it occurs more often in people arriving from tropical countries that have poor sanitary conditions, in individuals in institutions for the developmentally disabled, and in men who have sex with men. Progress in the epidemiology of amoebiasis has not only suffered from. Dpdx is an educational resource designed for health professionals and laboratory scientists. The structure and life cycle of entamoeba with diagram. Entamoeba histolytica and entamoeba dispar basic guidelines a. In most infected individuals the trophozoites exist as commensals. Amebiasis chapter 4 2020 yellow book travelers health. In the united states, infections caused by giardia and cryptosporidium are most prevalent. Pdf understanding the epidemiology of entamoeba histolytica. The epidemiology of entamoeba histolytica in a nigerian urban population.
Introduction the protozoan parasite, entamoeba histolytica, is the causative agent of amoebiasis in humans. The epidemiology of entamoeba histolytica infection in sudan is poorly understood. Entamoeba histolytica distribution parasite has worldwide distribution but is most common in the tropical and subtropical areas of the world. Amebiasis is distributed worldwide, particularly in the tropics, most commonly in areas of poor sanitation. Losch discovered amoeba in ulcers of the colon at autopsy and induced it to a. Traditionally, about onetenth of the world population is stated to be infected with e. 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 invasive, pathogenic protozoan, causing. Largely an infection of impoverished communities in developing countries, amebiasis has emerged as an important infection among returning. Pdf the epidemiology of entamoeba histolytica infection in sudan is poorly understood. Epidemiology surveillance system little is known of the epidemiology of amebiasis from e. Entamoeba histolytica is an anaerobic parasitic amoebozoan, part of the genus entamoeba.
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