Over 10 million scientific documents at your fingertips. Entamoeba histolytica is found worldwide but is more prevalent in people of lower socioeconomic status who live in resourcelimited countries, where the prevalence of amebic infection may. Identification of entamoeba histolytica trophozoites in fresh. Amebiasis is a common cause of diarrhea in infants in lowincome countries.
Entamoeba histolytica multiplies by binary fission in the trophozoite stage. Endocytotic vacuoles are often numerous and the parasite will ingest bacteria, leukocytes, and erythrocytes dark circles in trophozoites, above although it is. This study developed a fast and high throughput dotblot technique to evaluate the presence of entamoeba in stool samples n 643 followed by a pcrbased method to validate and differentiate the two species e. Entamoeba histolytica is a an anaerobic parasitic protozoan that is responsible for the development of amoebiasis. Its possible role as an element of the innate immune response jorgetonatiuh ayalasumuano, victor m. In this article we will discuss about the life history of entamoeba histolytica explained with diagram. Amoebiasis, also known amoebic dysentery, is an infection caused by any of the amoebae of the entamoeba group. Amebiasis is caused by entamoeba histolytica see the image below, a protozoan that is found worldwide see etiology. Several protozoan species in the genus entamoeba colonize humans, but not all of them are associated with disease. Culture of entamoeba histolytica after preparation of culture media added small amount 0.
Introduction the protozoan parasite, entamoeba histolytica, is the causative agent of amoebiasis in humans. Entamoeba histolytica is well recognized as a pathogenic ameba, associated with intestinal and extraintestinal infections. Entamoeba histolytica, the causative agent of amebiasis, was first described in 1875. Entamoeba histolytica epidemiology a worldwide distribution. Entamoeba coli is a nonpathogenic species of entamoeba that frequently exists as a commensal parasite in the human gastrointestinal tract. Pathogenesis of infection by entamoeba histolytica springerlink.
Infection by entamoeba histolytica occurs by ingestion of mature cysts 2 in fecally contaminated food, water, or hands. Traditionally, about onetenth of the world population is stated to be infected with e. Pdf epidemiology of entamoeba infection in sudan researchgate. The genus entamoeba has many species that are invasive or noninvasive e. The epidemiology of entamoeba histolytica infection in sudan is poorly understood. However, in the phylogenetic classification of living organisms, the family entamoebidae, which includes e. A higher prevalence in tropical and subtropical countries 10 % of the world population carries the parasite. Systematic detection and association of entamoeba species. To maximize recovery of cysts, stool samples in formalin, or other fixatives, should be concentrated prior to microscopic examination e. How do i view different file formats pdf, doc, ppt, mpeg on this site.
The epidemiology of entamoeba histolytica has been complicated by the mid1990s redescription of e. We conducted a retrospective study at the travel clinic of the institute of tropical medicine, antwerp, belgium on travelersmigrants found from 2006 to 2016 positive for entamoeba histolytica dispar through antigen detection andor through microscopy confirmed by pcr. Thus, reducing this contamination is the best method of prevention. Entamoeba histolytica is an enteric protozoan parasite with worldwide distribution. Most infections are asymptomatic, but may occasionally cause intestinal or extraintestinal disease. With increased travel and emigration to developed countries, infection is becoming more common in nonendemic areas. However, trophozoites can invade the colonic epithelium.
The occurrence of entamoeba histolytica as a human intestinal parasite is a serious problem especially in developing countries. Entamoeba histolytica is an invasive enteric protozoan parasite that is the cause of amebiasis. Excystation occurs in the small intestine with the release of motile trophozoites, which migrate to the large intestine. Amebiasis is an intestinal illness caused by a microscopic parasite called entamoeba histolytica. Longterm travelers duration 6 months are significantly more likely than shortterm travelers duration histolytica infection. It is a parasite that infects an estimated 50 million people around the world and is a significant cause of morbidity and mortality in developing countries. The epidemiology of entamoeba histolytica in mexico city. Entamoeba histolytica frequently infest as a commensal within the human large intestines with no overt clinical manifestations.
For this purpose, we performed the genotyping of entamoeba isolates and the. Entamoeba histolytica an overview sciencedirect topics. Entamoeba histolytica a number of outbreaks have resulted from a breakdown in sanitation or behavioral practices of people. Complications can include inflammation and ulceration of the colon with tissue death. Cultivation of entamoeba histolytica and entamoeba. The laboratory diagnosis of entamoeba histolytica article pdf available in bulletin of the new york academy of medicine 573. Risk factors for infection by the entamoeba histolyticae. Entamoeba dispar, morphologically indistinguishable from e. Tolllike receptor signaling activation by entamoeba histolytica induces beta defensin 2 in human colonic epithelial cells. 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. Although many people harbour this organism world wide, only about 10% develop clinically. The gastrointestinal pathogen entamoeba histolytica causes amoebiasis. Entamoeba histolytica is the responsible parasite of amoebiasis and remains one of the top three parasitic causes of mortality worldwide.
About 10% develop invasive amoebiasis, which leads to 40 000110 000 deaths per annum. Pdf the laboratory diagnosis of entamoeba histolytica. Abdominal tenderness and weight loss are common with amebic colitis. It is the third leading parasite cause of death in the developing countries. In 1984, at least 40,000 deaths were attributed to amoebiasis. Pdf the epidemiology of entamoeba histolytica infection in sudan is poorly understood. Pdf prevalence of e histolytica kunle sanyaolu and. It is responsible for amoebic dysentery bloody diarrhea and invasive extraintestinal amebiasis such as liver abscess, peritonitis, pleuropulmonary abscess.
Understanding the 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. Entamoeba histolytica is an anaerobic parasitic protozoan that infects the digestive tract of predominantly humans and other primates. Of these entamoeba histolytica is the only species found to be associated with intestinal disease. Oti and others published understanding the epidemiology of entamoeba histolytica infections find, read and cite all the research. The detection of entamoeba histolytica, the causative agent of amebiasis. Amongthe260dotblot positive samples,monoinfections ofe. Ingestion of contaminated food or water with amoebae cyst infective stage. Entamoeba histolytica, the causative agent of amebiasis or amoebiasis is. The protozoan entamoeba histolytica is the causative agent of amebiasis. Although the majority of individuals infected with e. Entamoeba histolytica and entamoeba dispar basic guidelines a.
Entamoeba histolytica is an intestinal protozoan parasite and the causative agent of invasive amebiasis. The other species are important because they may be confused with e. 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. Entamoeba histolytica introduction there is a large number of species of amoebae which parasitise the human intestinal tract. The antigen was a mixture of membrane proteins obtained by triton x100 extraction from an axenic culture of entamoeba histolytica hm1imss. The trophozoites are 2030 m in diameter and contain a vesicular nucleus with a central endosome, peripheral chromatin and radial achromatic fibrils imparting a cartwheel appearance. Recent immigrants and refugees from these areas are also at risk. Molecular differentiation of entamoeba histolytica and. Cultivation of entamoeba histolytica and entamoeba histolytica like strains at reduced temperature and behavior of the amebae in diluted media. Differentiation is possible, but not always easy, based on morphologic characteristics of the.
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. First molecular epidemiology of entamoeba histolytica, e. Phylogenetic analysis of ribosomal rna gene sequences has demonstrated the monophyletic nature of the entamoeba genus silberman et al. Life cycle of entamoeba histolytica infective cysts are ingested excystation occurs in small intestine, releasing 4 amoebae which divide into 8 amoebae pass to large intestine and divide into trophozoites form cysts that pass with feces. Entamoeba histolytica modes of transmission human being is the principle host source of infection. Entamoeba histolytica amebiasis infectious disease and. Laboratory diagnostic techniques for entamoeba species ncbi. All files of individuals with a positive pcr for e. The prevalence rate of the parasite has been detected in a crosssectional study carried out in the population of the eastern and northern parts of. Amoebiasis can be present with no, mild, or severe symptoms.
Amebiasis, due to the pathogenic parasite entamoeba histolytica, is a leading cause of diarrhea globally. Oti and others published understanding the epidemiology of entamoeba histolytica infections find, read and cite all the research you need on researchgate. Largely an infection of impoverished communities in developing countries, amebiasis has emerged as an important infection among returning. Further molecular studies have identified a third species, e. Amoebiasis or more correctly it should be called as amoebic dysentery is caused by a protozoan parasite known as entamoeba histolytica.
Although a large number of people throughout the world are infected with this organism, only a small. View entamoeba histolytica research papers on academia. Entamoeba coli life cycle and location identical to. Entamoeba histolytica is an anaerobic parasitic amoebozoan, part of the genus entamoeba. An epidemiological study was conducted on a population attending outpatient clinics in manaus, amazon, brazil to determine the prevalences of infection by the entamoeba histolytica e. Clipboard, search history, and several other advanced features are temporarily unavailable. Life history of entamoeba histolytica parasitology. The method was standardized by comparing serum samples.
The main objectives of the present work were to determine the molecular frequency and the dynamic of infection of e. The parasite is responsible for amoebiasis and liver absceses. Similarly entamoeba moshkovskii, which was long considered to be a freeliving amoeba is also morphologically identical to e. Our understanding of its epidemiology has dramatically changed since this amoeba was distinguished from another morphologically similar one, entamoeba dispar, a non. Pdf understanding the epidemiology of entamoeba histolytica. Molecular differentiation of entamoeba histolytica entamoeba. Outbreaks have occurred following water supply contamination, as the cysts are resistant. Symptoms may include abdominal pain, diarrhea, or bloody diarrhea.
It belongs to the subphylum it belongs to the subphylum sarcodina, class lobosea, and family entamoebidae. Amebiasis is distributed worldwide, particularly in the tropics, most commonly in areas of poor sanitation. This kind of protozoan parasite resides in the mucous and submucous layer of the large intestine specially at the iliocaec. Entamoeba histolytica, the causative agent of amebiasis, is a protozoan parasite that accounts for an estimated 100,000 annual deaths globally.
This kind of protozoan parasite resides in the mucous and submucous layer of the large intestine specially. In a small percentage of infections, the trophozoites become invasive and. The prevalence of antibodies against entamoeba histolytica was studied in the mexican population using an immunoenzyme assay in solid phase elisa and semiautomatic equipment. Studies on the epidemiology of amebiasisin endemic areas have used molecular. Little is known of the epidemiology of amebiasis from e. Patients may present months to years after the initial infection. Ingestion of fecally contaminated food or water is the primary mode of transmission. It was not until 1993 that diamond and clark 1993 gave the ultimate redescription of e. Amoebiasis is caused by the parasite entamoeba histolytica. Prevention and control of amoebic dysentery in hong kong.
Progress in the epidemiology of amoebiasis has not only suffered from. Predominantly infecting humans and other primates causing amoebiasis, e. Morphology, life cycle, pathogenesis, clinical manifestation, lab diagnosis and treatment entamoeba histolytica is a common protozoan parasite found in the large intestine of human. Biochemical analysis has indicated that glutathione is not present. Prevalence of antibodies against entamoeba histolytica in.
Entamoeba histolytica causes amoebic dysentery in man and primates. Infection typically begins with the ingestion of mature, quadrinucleated cysts found in fecally contaminated food or water. Entamoeba histolytica causes about 50 million infections worldwide with a death rate of over 100,000 annually. Entamoeba histolytica neglected tropical diseases e3s web of. Amebiasis, amebic dysentery, ameboma characteristics. Dientamoeba fragilis which is a flagellate not an ameba. According to the best estimates walsh 1986 approximately 48 million individuals suffer from amoebiasis throughout the world. Clinical severity ranges from the asymptomatic passage of cysts in the stool to fulminant dysentery. Symptoms are most common during infection by entamoeba histolytica. Infection ranges from mostly asymptomatic colonization of the large bowel to invasive and potentially fatal intestinal and extraintestinal disease, with a special predilection for liver abscess formation. Clinical notification of reportable diseases and conditions. Entamoeba histolytica must be differentiated from other intestinal protozoa including. Excystation 3 occurs in the small intestine and trophozoites 4 are released, which migrate to the large intestine.
Entamoeba histolytica distribution parasite has worldwide distribution but is most common in the tropical and subtropical areas of the world. Entamoeba histolytica is an invasive, pathogenic protozoan. In endemic developing countries where resources are limited, microscopic examinations based on wheatley trichrome staining is commonly used for diagnosis of intestinal amoebiasis. The northeastern part of india is a hot spot of infection since the climatic conditions are. A possible function of entamoeba histolytica in the creation. Potentially fatal extraintestinal amoebiasis, including amoebic liver abscess, complicates 1%3% of infections. Histopathological study of invasive and noninvasive entamoeba. House flies and cockroaches mechanical transmission. Amoebiasis caused by entamoeba histolytica is an important issue in world public health because it is associated with. Research article open access entamoeba histolytica and. Entamoeba histolytica is a pseudopodforming nonflagellate protozoan parasite. Old methods used such as direct microscopy and culturing are insensitive compared to polymerase chain reaction pcr. Life cycle cysts ingested by man reach the colon where reversion to trophozoites occurs and.
Review paper public health and clinical importance of. Therefore as far back as in 1925 a concept of the existence of two morphologically identical amoeba species was formulated brumpt 1925. The disease is common in tropical regions of the world where hygiene and sanitation is often approximate. Amebiasis also causes colitis that can present with diarrhea andor dysentery that can be acute or last more than 1 week. Entamoeba gingivalis entamoeba gingivalis is an entamoeba histolytica like amoebae that lives inon the teeth, gums, and sometimes tonsils. These molecular methods have led to a reevaluation of the epidemiology of amebiasis in terms of.
Entamoeba histolytica is an anaerobic parasitic protozoan, part of the genus entamoeba. In most infected individuals the trophozoites exist as commensals. Entamoeba histolytica is a protozoan parasite that causes amebic dysentery and liver abscess. It contains four nuclei when mature, one nucleus when immature with glycogen in a. The highest prevalence of amebiasis is in developing countries where barriers between human feces and food and water supplies are inadequate see epidemiology. Entamoeba histolytica material safety data sheet infectious substances section i infectious agent name. 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 a protozoan endoparasite inhabiting the mucosa and submucosa layers of the large intestine of human beings, causing dysentery and liver abscess.