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Virulence Dec 2023The amoeba parasite is the causative agent of human amebiasis, an enteropathic disease affecting millions of people worldwide. This ancient protozoan is an elementary... (Review)
Review
The amoeba parasite is the causative agent of human amebiasis, an enteropathic disease affecting millions of people worldwide. This ancient protozoan is an elementary example of how parasites evolve with humans, e.g. taking advantage of multiple mechanisms to evade immune responses, interacting with microbiota for nutritional and protective needs, utilizing host resources for growth, division, and encystation. These skills of perpetuate the species and incidence of infection. However, in 10% of infected cases, the parasite turns into a pathogen; the host-parasite equilibrium is then disorganized, and the simple lifecycle based on two cell forms, trophozoites and cysts, becomes unbalanced. Trophozoites acquire a virulent phenotype which, when non-controlled, leads to intestinal invasion with the onset of amoebiasis symptoms. Virulent must cross mucus, epithelium, connective tissue and possibly blood. This highly mobile parasite faces various stresses and a powerful host immune response, with oxidative stress being a challenge for its survival. New emerging research avenues and omics technologies target gene regulation to determine human or parasitic factors activated upon infection, their role in virulence activation, and in pathogenesis; this research bears in mind that is a resident of the complex intestinal ecosystem. The goal is to eradicate amoebiasis from the planet, but the parasitic life of is ancient and complex and will likely continue to evolve with humans. Advances in these topics are summarized here.
Topics: Humans; Entamoeba histolytica; Virulence; Ecosystem; Amebiasis; Intestines
PubMed: 36519347
DOI: 10.1080/21505594.2022.2158656 -
Canadian Journal of Gastroenterology &... 2018is the responsible parasite of amoebiasis and remains one of the top three parasitic causes of mortality worldwide. With increased travel and emigration to developed... (Review)
Review
is the responsible parasite of amoebiasis and remains one of the top three parasitic causes of mortality worldwide. With increased travel and emigration to developed countries, infection is becoming more common in nonendemic areas. Although the majority of individuals infected with remain asymptomatic, some present with amoebic colitis and disseminated disease. As more is learned about its pathogenesis and the host's immune response, the potential for developing a vaccine holds promise. This narrative review outlines the current knowledge regarding and and insight in the development of a vaccine.
Topics: Antiprotozoal Agents; Dysentery, Amebic; Entamoeba histolytica; Entamoebiasis; Humans; Protozoan Vaccines; Travel
PubMed: 30631758
DOI: 10.1155/2018/4601420 -
International Journal of Molecular... Jul 2023This review of human amoebiasis is based on the most current knowledge of pathogenesis, diagnosis, treatment, and Entamoeba/microbiota interactions. The most relevant... (Review)
Review
This review of human amoebiasis is based on the most current knowledge of pathogenesis, diagnosis, treatment, and Entamoeba/microbiota interactions. The most relevant findings during this last decade about the parasite and the disease are related to the possibility of culturing trophozoites of different isolates from infected individuals that allowed the characterization of the multiple pathogenic mechanisms of the parasite and the understanding of the host-parasite relationship in the human. Second, the considerable advances in molecular biology and genetics help us to analyze the genome of , their genetic diversity, and the association of specific genotypes with the different amoebic forms of human amoebiasis. Based on this knowledge, culture and/or molecular diagnostic strategies are now available to determine the species and genotype responsible for invasive intestinal or extraintestinal amoebiasis cases. Likewise, the extensive knowledge of the immune response in amoebiasis with the appearance of new technologies made it possible to design diagnostic tools now available worldwide. Finally, the understanding of the interaction between the species and the intestinal microbiota aids the understanding of the ecology of this parasite in the human environment. These relevant findings will be discussed in this review.
Topics: Humans; Entamoeba histolytica; Ecosystem; Amebiasis; Dysentery, Amebic; Intestines; Entamoeba
PubMed: 37511519
DOI: 10.3390/ijms241411755 -
International Journal of Medical... Jan 2020Amoebiasis is a parasitic disease caused by Entamoeba histolytica (E. histolytica), an extracellular enteric protozoan. This infection mainly affects people from... (Review)
Review
Amoebiasis is a parasitic disease caused by Entamoeba histolytica (E. histolytica), an extracellular enteric protozoan. This infection mainly affects people from developing countries with limited hygiene conditions, where it is endemic. Infective cysts are transmitted by the fecal-oral route, excysting in the terminal ileum and producing invasive trophozoites (amoebae). E. histolytica mainly lives in the large intestine without causing symptoms; however, possibly as a result of so far unknown signals, the amoebae invade the mucosa and epithelium causing intestinal amoebiasis. E. histolytica possesses different mechanisms of pathogenicity for the adherence to the intestinal epithelium and for degrading extracellular matrix proteins, producing tissue lesions that progress to abscesses and a host acute inflammatory response. Much information has been obtained regarding the virulence factors, metabolism, mechanisms of pathogenicity, and the host immune response against this parasite; in addition, alternative treatments to metronidazole are continually emerging. An accesible and low-cost diagnostic method that can distinguish E. histolytica from the most nonpathogenic amoebae and an effective vaccine are necessary for protecting against amoebiasis. However, research about the disease and its prevention has been a challenge due to the relationship between E. histolytica and the host during the distinct stages of the disease is multifaceted. In this review, we analyze the interaction between the parasite, the human host, and the colon microbiota or pathogenic microorganisms, which together give rise to intestinal amoebiasis.
Topics: Amebiasis; Animals; Antiprotozoal Agents; Developing Countries; Dysentery, Amebic; Entamoeba histolytica; Feces; Gastrointestinal Microbiome; Host-Pathogen Interactions; Humans; Intestines; Metronidazole; Mice; Public Health; Virulence
PubMed: 31587966
DOI: 10.1016/j.ijmm.2019.151358 -
BMJ Clinical Evidence Aug 2013Amoebic dysentery is caused by the protozoan parasite Entamoeba histolytica. It is transmitted in areas where poor sanitation allows contamination of drinking water and... (Review)
Review
INTRODUCTION
Amoebic dysentery is caused by the protozoan parasite Entamoeba histolytica. It is transmitted in areas where poor sanitation allows contamination of drinking water and food with faeces. In these areas, up to 40% of people with diarrhoea may have amoebic dysentery.
METHODS AND OUTCOMES
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of drug treatments for amoebic dysentery in endemic areas? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS
We found 6 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS
In this systematic review, we present information relating to the effectiveness and safety of the following interventions: diiodohydroxyquinoline (iodoquinol), diloxanide, emetine, metronidazole, nitazoxanide, ornidazole, paromomycin, secnidazole, and tinidazole.
Topics: Administration, Oral; Diarrhea; Dysentery, Amebic; Entamoeba histolytica; Feces; Humans; Metronidazole; Paromomycin; Tinidazole
PubMed: 23991750
DOI: No ID Found -
BMJ Clinical Evidence Jan 2011Amoebic dysentery is caused by the protozoan parasite Entamoeba histolytica. It is transmitted in areas where poor sanitation allows contamination of drinking water and... (Review)
Review
INTRODUCTION
Amoebic dysentery is caused by the protozoan parasite Entamoeba histolytica. It is transmitted in areas where poor sanitation allows contamination of drinking water and food with faeces. In these areas, up to 40% of people with diarrhoea may have amoebic dysentery.
METHODS AND OUTCOMES
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of drug treatments for amoebic dysentery in endemic areas? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS
We found 6 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS
In this systematic review, we present information relating to the effectiveness and safety of the following interventions: diiodohydroxyquinoline (iodoquinol), diloxanide, emetine, metronidazole, nitazoxanide, ornidazole, paromomycin, secnidazole, and tinidazole.
Topics: Administration, Oral; Diarrhea; Dysentery, Amebic; Entamoeba histolytica; Humans; Incidence; Iodoquinol; Metronidazole; Paromomycin; Tinidazole
PubMed: 21477391
DOI: No ID Found -
Frontiers in Cellular and Infection... 2019
Topics: Amebicides; Anisomycin; Asymptomatic Diseases; Drug Discovery; Dysentery, Amebic; Entamoeba histolytica; Flavonoids; Gene Expression Regulation; Humans; Life Cycle Stages; Metabolic Networks and Pathways; Metronidazole; Piperidines; Prodigiosin; Protozoan Proteins; Pyridines; Severity of Illness Index
PubMed: 31338336
DOI: 10.3389/fcimb.2019.00247 -
BMJ Clinical Evidence Jan 2007Amoebic dysentery is caused by the protozoan parasite Entamoeba histolytica. It is transmitted in areas where poor sanitation allows contamination of drinking water and... (Review)
Review
INTRODUCTION
Amoebic dysentery is caused by the protozoan parasite Entamoeba histolytica. It is transmitted in areas where poor sanitation allows contamination of drinking water and food with faeces. In these areas, up to 40% of people with diarrhoea may have amoebic dysentery.
METHODS AND OUTCOMES
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of drug treatments for amoebic dysentery in endemic areas? We searched: Medline, Embase, The Cochrane Library and other important databases up to July 2006 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS
We found 11 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS
In this systematic review we present information relating to the effectiveness and safety of the following interventions: emetine, metronidazole, ornidazole, paromomycin, secnidazole, and tinidazole.
Topics: Administration, Oral; Antibodies, Protozoan; Diarrhea; Dysentery, Amebic; Entamoeba histolytica; Feces; Gene Library; Humans; Metronidazole; Tinidazole
PubMed: 19454043
DOI: No ID Found -
Mucosal Immunology Sep 2012Enhanced susceptibility to infection has long been recognized in children with congenital deficiency of leptin or its receptor. Studies in mice have demonstrated that... (Review)
Review
Enhanced susceptibility to infection has long been recognized in children with congenital deficiency of leptin or its receptor. Studies in mice have demonstrated that leptin deficiency affects both the innate and acquired immune systems. Here, we review recent studies that demonstrate the impact on immunity of a common non-synonomous polymorphism of the leptin receptor. In a Bangladesh cohort of children, the presence of two copies of the ancestral Q223 allele was significantly associated with resistance to amebiasis. Children and mice with at least one copy of the leptin receptor 223R mutation were more susceptible to amebic colitis. Leptin signaling in the intestinal epithelium and downstream STAT3 (signal transducer and activator of transcription 3) and SHP2 (Src homology phosphatase 2) signaling were required for protection in the murine model of amebic colitis. Murine models have also implicated leptin in protection from other infections, including Mycobacterium tuberculosis, Klebsiella pneumoniae, and Streptococcus pneumoniae. Thus, the role of leptin signaling in infectious disease and specifically leptin-mediated protection of the intestinal epithelium will be the focus of this review.
Topics: Animals; Child; Disease Models, Animal; Dysentery, Amebic; Genetic Predisposition to Disease; Humans; Immunity, Mucosal; Intestinal Mucosa; Leptin; Mice; Polymorphism, Genetic; Protein Tyrosine Phosphatase, Non-Receptor Type 11; Receptors, Leptin; STAT3 Transcription Factor; Signal Transduction
PubMed: 22692456
DOI: 10.1038/mi.2012.40 -
Annals of Agricultural and... May 2017[b]Abstract Introduction[/b]. Among free-living amoebae that are widely distributed in nature only four genera/species are known as agents of human infections:[i]... (Review)
Review
[b]Abstract Introduction[/b]. Among free-living amoebae that are widely distributed in nature only four genera/species are known as agents of human infections:[i] Acanthamoeba spp., Naegleriafowleri, Balamuthia mandrillaris[/i] and[i] Sappiniapedata[/i]. These amoebae are not well adapted to parasitism, and could exist in the human environment without the need for a host. Infections due to these amoebae, despite low morbidity, are characterized by relatively high mortality rate and pose serious clinical problems. [b]Objectve[/b]. This review study presents and summarizes current knowledge about infections due to pathogenic and opportunistic free-living amoebae focused on epidemiology, clinical manifestations, diagnosis and treatment based on global literature. [b]State of knowledge[/b]. All four genera have been recognized as etiologic factors of fatal central nervous system infections and other serious diseases in humans. [i]N. fowleri[/i] causes an acute fulminating meningoencephalitis in children and young adults. [i]Acanthamoeba spp[/i]. and [i]B.mandrillaris[/i] are opportunistic pathogens causing granulomatous amoebic encephalitis and disseminated or localized infections which could affect the skin, sinuses, lungs, adrenals and/or bones. [i]Acanthamoeba spp[/i]. is also the main agent of acute eye infection -[i] Acanthamoeba keratitis, [/i]mostly in contact lens wearers. However, there is only one recognized case of encephalitis caused by [i]S. pedata. [/i] [b]Conclusions[/b]. Amoebic diseases are difficult to diagnose which leads to delayed treatment, and result in a high mortality rate. Considering those issues, there is an urgent need to draw more attention to this type of diseases.
Topics: Amebiasis; Amoeba; Animals; Humans
PubMed: 28664704
DOI: 10.5604/12321966.1233568