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Li J, Cui Z, Li X, Zhang L. Review of zoonotic amebiasis: Epidemiology, clinical signs, diagnosis, treatment, prevention and control. Res Vet Sci 2021; 136:174-181. [PMID: 33676155 DOI: 10.1016/j.rvsc.2021.02.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 01/11/2021] [Accepted: 02/26/2021] [Indexed: 02/07/2023]
Abstract
Amebiasis is a disease caused by the protozoan parasite Entamoeba histolytica, which mainly shows symptoms of acute diarrhea, dysentery, amebic colitis, and amebic liver abscesses. As the fourth leading parasitic cause of human mortality, E. histolytica mainly infect children in developing countries, transmitted by food and water contamination. In the majority of infected individuals, Entamoeba sp. asymptomatically colonizes the large intestine and self-limiting, while in others, the parasite breaches the mucosal epithelial barrier to cause amebic colitis and can disseminate to soft organs to cause abscesses. Metronidazole (MTZ) is the recommended and most widely used drug for treating the invasive amebiasis. No amebiasis vaccine has been approved for human clinical trials to date, but many recent vaccine development studies hold promise. For the prevention and control of amebiasis, improvement of water purification systems and hygiene practices could decrease disease incidence. In this review, we focus on the epidemiology, transmission, clinical signs, pathogenesis, diagnosis, treatment, prevention and control of the zoonotic amebiasis.
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Affiliation(s)
- Junqiang Li
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
| | - Zhaohui Cui
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
| | - Xiaoying Li
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China
| | - Longxian Zhang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China.
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Cui Z, Li J, Chen Y, Zhang L. Molecular epidemiology, evolution, and phylogeny of Entamoeba spp. INFECTION GENETICS AND EVOLUTION 2019; 75:104018. [PMID: 31465857 DOI: 10.1016/j.meegid.2019.104018] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 08/20/2019] [Accepted: 08/22/2019] [Indexed: 01/11/2023]
Abstract
Entamoeba histolytica is a protozoan parasite and the causative agent of amoebiasis in humans. The estimations of the worldwide burden of amoebiasis by the WHO indicated that approximately 500 million people were infected with the parasite and 10% of these individuals had invasive amoebiasis. However, our understanding of the disease burden and epidemiology of human amebiasis has undergone dramatic changes over the last two decades based on molecular analyses. The development of Entamoeba genomics has also provided some interesting and valuable information on the evolution and population structure of this parasite. In addition, the use of a number of molecular markers has greatly expanded our understanding of Entamoeba host range and genetic diversity. In this review, we re-assessed Entamoeba prevalence and species in humans, non-human primates, other animals, and the environment in the context of molecular data. Some issues regarding the evolution and phylogeny of different Entamoeba species lineages are also discussed.
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Affiliation(s)
- Zhaohui Cui
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; National International Joint Research Center for Veterinary Immunology, Zhengzhou, China
| | - Junqiang Li
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; National International Joint Research Center for Veterinary Immunology, Zhengzhou, China; Scientific Research Experiment Center & Laboratory Animal Center, Henan University of Chinese Medicine, Zhengzhou 450046, China
| | - Yuancai Chen
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; National International Joint Research Center for Veterinary Immunology, Zhengzhou, China
| | - Longxian Zhang
- College of Animal Science and Veterinary Medicine, Henan Agricultural University, Zhengzhou 450002, China; National International Joint Research Center for Veterinary Immunology, Zhengzhou, China.
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Roure S, Valerio L, Soldevila L, Salvador F, Fernández-Rivas G, Sulleiro E, Mañosa M, Sopena N, Mate JL, Clotet B. Approach to amoebic colitis: Epidemiological, clinical and diagnostic considerations in a non-endemic context (Barcelona, 2007-2017). PLoS One 2019; 14:e0212791. [PMID: 30789955 PMCID: PMC6383915 DOI: 10.1371/journal.pone.0212791] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 02/08/2019] [Indexed: 11/19/2022] Open
Abstract
Background Amoebic colitis is the most frequent clinical manifestation of invasive intestinal infection due to Entamoeba histolytica and a common cause of diarrhoea worldwide. Since higher transmission rates are usually related to poor health and exposure to unhygienic conditions, cases reported in Europe usually involve immigrants and international travellers. The goal of this study was to characterise both the clinical and the epidemiological features of a European population diagnosed with amoebic colitis and then to evaluate the diagnostic tools and therapeutic options applied. Methods and results This was a retrospective observational study in which data from all patients diagnosed with amoebic colitis attending at the International Health Units of two tertiary referral hospitals, Germans Trias i Pujol University Hospital (Badalona, North Barcelona Metropolitan Area) and Vall d’Hebron University Hospital (Barcelona city) between 2007 and 2017 were analysed. During the study period 50 patients were diagnosed with amoebic colitis. Thirty-six (72%) were men, and immigrants accounted for 46% of all cases. Antecedents of any international travel were reported for 28 (56%), the most frequent destinations having been the Indian subcontinent, South and Central America and sub-Saharan Africa. Preexisting pathological conditions or any kind of immunosuppression were identified in 29 (58%) patients; of these, 13 (26%) had HIV infection—all of them men who have sex with men—and 5 (10%) had inflammatory bowel disease. Diarrhoea, abdominal pain and dysentery were the most frequently recorded symptoms of invasive amoebae. Diagnosis was made through microbiological study in 45 (90%) and/or histological identification of amoebae in colon biopsies in 10 (20%). After treatment with metronidazole (82%) or tinidazole (8%), all patients had good outcomes. Post-acute intraluminal treatment was indicated in 28 (56%). Conclusions Amoebic colitis should be suspected in patients with diarrhoea and compatible epidemiological risk factors (immigration, travelling abroad or men who have sex with men), especially if some degree of immunosuppression concurs. These risk factors must be taken into account in any diagnostic approach to inflammatory bowel disease (IBD), and active searches for stool parasites should be performed in such cases to rule out misdiagnosis or simultaneous amoebic infection. Treatment should include intraluminal anti-amoebic treatment in order to avoid relapse and prevent further spread of the disease.
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Affiliation(s)
- Sílvia Roure
- Infectious Disease Department, North Metropolitan International Health Unit PROSICS, Germans Trias i Pujol University Hospital, Universitat Autònoma de Barcelona, Badalona, Spain
- North Metropolitan International Health Unit PROSICS, Institut Català de la Salut, Santa Coloma de Gramenet, Barcelona, Spain
- * E-mail:
| | - Lluís Valerio
- North Metropolitan International Health Unit PROSICS, Institut Català de la Salut, Santa Coloma de Gramenet, Barcelona, Spain
| | - Laura Soldevila
- Infectious Disease Department, North Metropolitan International Health Unit PROSICS, Germans Trias i Pujol University Hospital, Universitat Autònoma de Barcelona, Badalona, Spain
| | - Fernando Salvador
- Infectious Disease Department, Vall d’Hebron University Hospital, PROSICS Barcelona, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Gema Fernández-Rivas
- Microbiology Depatment, Clinical Laboratory North Metropolitan Area, Germans Trias i Pujol University Hospital, Departament of Genetics and Microbiology, Autonomous University of Barcelona, Badalona, Spain
| | - Elena Sulleiro
- Microbiology Department, Vall d’Hebron University Hospital. PROSICS Barcelona, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Míriam Mañosa
- Inflammatory Bowel Disease Unit, Gastroenterology Department,Germans Trias i Pujol University Hospital and Centro de Investigaciones Biomédicas en Red de Enfermedades Hepáticas y Digestivas, Badalona, Spain
| | - Nieves Sopena
- Infectious Diseases Department, Germans Trias i Pujol University Hospital, Universitat Autònoma de Barcelona, Badalona, Spain
| | - José Luis Mate
- Department of Pathological Anatomy, Germans Trias i Pujol University Hospital, Badalona, Spain
| | - Bonaventura Clotet
- Infectious Disease Department, AIDS Research Institute-IrsiCaixa, Germans Trias i Pujol University Hospital, Universitat Autònoma de Barcelona, Badalona, Spain
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Mwendwa F, Mbae CK, Kinyua J, Mulinge E, Mburugu GN, Njiru ZK. Stem loop-mediated isothermal amplification test: comparative analysis with classical LAMP and PCR in detection of Entamoeba histolytica in Kenya. BMC Res Notes 2017; 10:142. [PMID: 28359328 PMCID: PMC5374617 DOI: 10.1186/s13104-017-2466-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 03/24/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Entamoeba histolytica, the causative agent for amoebiasis is a considerable burden to population in the developing countries where it accounts for over 50 million infections. The tools for detection of amoebiasis are inadequate and diagnosis relies on microscopy which means a significant percent of cases remain undiagnosed. Moreover, tests formats that can be rapidly applied in rural endemic areas are not available. METHODS In this study, a loop-mediated isothermal test (LAMP) based on 18S small subunit ribosomal RNA gene was designed with extra reaction accelerating primers (stem primers) and compared with the published LAMP and PCR tests in detection of E. histolytica DNA in clinical samples. RESULTS The stem LAMP test indicated shorter time to results by an average 11 min and analytical sensitivity of 10-7 (~30 pg/ml) compared to the standard LAMP and PCR which showed sensitivities levels of 10-5 (~3 ng/ml) and 10-4 (~30 ng/ml) respectively using tenfold serial dilution of DNA. In the analysis of clinical specimens positive for Entamoeba spp. trophozoites and cysts using microscopy, the stem LAMP test detected E. histolytica DNA in 36/126, standard LAMP test 20/126 and PCR 17/126 cases respectively. There was 100% agreement in detection of the stem LAMP test product using fluorescence of SYTO-9 dye in real time machine, through addition of 1/10 dilution of SYBR® Green I and electrophoresis in 2% agarose gel stained with ethidium bromide. CONCLUSION The stem LAMP test developed in this study indicates potential towards detection of E. histolytica.
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Affiliation(s)
- Fridah Mwendwa
- Institute of Tropical Medicine and Infectious Diseases, Jomo Kenyatta University of Agriculture and Technology, P.O Box 62000-0200, Nairobi, Kenya.
| | - Cecilia K Mbae
- Centre for Microbiology Research, Kenya Medical Research Institute, P.O Box 19464-00202, Nairobi, Kenya
| | - Johnson Kinyua
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, P.O Box 62000-0200, Nairobi, Kenya
| | - Erastus Mulinge
- Centre for Microbiology Research, Kenya Medical Research Institute, P.O Box 19464-00202, Nairobi, Kenya
| | | | - Zablon K Njiru
- Meru University of Science and Technology, P. O. Box 972-60200, Meru, Kenya.,School of Health Professions, Mandurah Campus, Murdoch University, Murdoch, WA, 6210, Australia
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Nowak P. Entamoeba histolytica - Pathogenic Protozoan of the Large Intestine in Humans. ACTA ACUST UNITED AC 2015. [DOI: 10.17352/jcmbt.000003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Oliveira FMS, Neumann E, Gomes MA, Caliari MV. Entamoeba dispar: Could it be pathogenic. Trop Parasitol 2015; 5:9-14. [PMID: 25709947 PMCID: PMC4327003 DOI: 10.4103/2229-5070.149887] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 01/22/2015] [Indexed: 12/30/2022] Open
Abstract
Amebiasis is a disease caused by the protozoan parasite Entamoeba histolytica. This ameba can colonize the human intestine and persist as a commensal parasite, similar to Entamoeba dispar, an ameba considered to be non-pathogenic. The similarities between E. histolytica and E. dispar make the latter an attractive model for studies aimed at clarifying the pathogenesis of amebiasis. However, in addition to being an interesting experimental model, this relative of E. histolytica remains poorly understood. In the 1990, it was believed that E. dispar was unable to produce significant experimental lesions. This scenario began to change in 1996, when E. dispar strains were isolated from symptomatic patients in Brazil. These strains were able to produce liver and intestinal lesions that were occasionally indistinguishable from those produced by E. histolytica. These and other findings, such as the detection of E. dispar DNA sequences in samples from patients with amebic liver abscess, have revived the possibility that this species can produce lesions in humans. The present paper presents a series of studies on E. dispar that begin to reveal a new facet of this protozoan.
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Affiliation(s)
- Fabrício Marcus Silva Oliveira
- Department of General Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Elisabeth Neumann
- Department of Microbiology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Maria Aparecida Gomes
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Marcelo Vidigal Caliari
- Department of General Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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7
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Lima ATB, de Souza VAB, Gomes RLF, Lima PSC. Molecular characterization of cajá, Spondias mombin (Anacardiaceae), by RAPD markers. GENETICS AND MOLECULAR RESEARCH 2011; 10:2893-904. [PMID: 22179961 DOI: 10.4238/2011.november.25.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The arboreal species Spondias mombin L. (Anacardiaceae) is widely distributed in Brazil, where the fruits, known by the common name of cajá, are an important commercial commodity. We evaluated genetic variability among 32 cajá accessions of the Germplasm Collection of Embrapa Meio-Norte using RAPD technique. Reaction conditions for efficient RAPD amplifications were optimized in preliminary tests, and primers were selected from a set designed by the University of British Columbia on the basis of high levels of polymorphism and adequate band resolution. The 21 primers employed in the final analysis produced 145 fragments, 79% of which were polymorphic. Based on the RAPD data, a dendrogram was constructed using the unweighted pair group method with arithmetic mean clustering technique. The 32 cajá accessions were classified into three main groups with a mean genetic similarity of 68.8%. Group I comprised 26 accessions (74.1% similarity), and group II included five accessions (74.0% similarity), while group III consisted of one accession (BGC 06), which exhibited the lowest similarity coefficients. Accessions BGC 06 and BGC 31 were the most unrelated and, hence, most suitable for initial crossings in order to obtain high levels of segregation. We concluded, based on the repeatability and reproducibility tests, that the RAPD technique is reliable and efficient for revealing the genetic diversity of cajá accessions, which will be useful for genetic improvement programs.
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Affiliation(s)
- A T B Lima
- Embrapa Meio-Norte, Teresina, PI, Brasil.
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8
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Lievens B, Frans I, Heusdens C, Justé A, Jonstrup SP, Lieffrig F, Willems KA. Rapid detection and identification of viral and bacterial fish pathogens using a DNA array-based multiplex assay. JOURNAL OF FISH DISEASES 2011; 34:861-875. [PMID: 21988358 DOI: 10.1111/j.1365-2761.2011.01304.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Fish diseases can be caused by a variety of diverse organisms, including bacteria, fungi, viruses and protozoa, and pose a universal threat to the ornamental fish industry and aquaculture. The lack of rapid, accurate and reliable means by which fish pathogens can be detected and identified has been one of the main limitations in fish pathogen diagnosis and fish disease management and has consequently stimulated the search for alternative diagnostic techniques. Here, we describe a method based on multiplex and broad-range PCR amplification combined with DNA array hybridization for the simultaneous detection and identification of all cyprinid herpesviruses (CyHV-1, CyHV-2 and CyHV-3) and some of the most important fish pathogenic Flavobacterium species, including F. branchiophilum, F. columnare and F. psychrophilum. For virus identification, the DNA polymerase and helicase genes were targeted. For bacterial identification, the ribosomal RNA gene was used. The developed methodology permitted 100% specificity for the identification of the target species. Detection sensitivity was equivalent to 10 viral genomes or less than a picogram of bacterial DNA. The utility and power of the array for sensitive pathogen detection and identification in complex samples such as infected tissue is demonstrated in this study.
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Affiliation(s)
- B Lievens
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Consortium for Industrial Microbiology and Biotechnology (CIMB), Department of Microbial and Molecular Systems (M2S), K.U. Leuven Association, Lessius Mechelen, Campus De Nayer, Sint-Katelijne-Waver,
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9
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Parasitic infections and myositis. Parasitol Res 2011; 110:1-18. [PMID: 21881948 DOI: 10.1007/s00436-011-2609-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 08/04/2011] [Indexed: 12/20/2022]
Abstract
Infectious myositis may be caused by a wide variety of bacterial, fungal, viral, and parasitic agents. Parasitic myositis is most commonly a result of trichinosis, cystericercosis, or toxoplasmosis, but other parasites may be involved. A parasitic cause of myositis is suggested by history of residence or travel to endemic area and presence of eosinophilia. The diagnosis of parasitic myositis is suggested by the clinical picture and radiologic imaging, and the etiologic agent is confirmed by parasitologic, serologic, and molecular methods, together with histopathologic examination of tissue biopsies. Therapy is based on the clinical presentation and the underlying pathogen. Drug resistance should be put into consideration in different geographic areas, and it can be avoided through the proper use of anti-parasitic drugs.
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Santos FLN, Gonçalves MDS, Soares NM. Validation and utilization of PCR for differential diagnosis and prevalence determination of Entamoeba histolytica/Entamoeba dispar in Salvador City, Brazil. Braz J Infect Dis 2011. [DOI: 10.1016/s1413-8670(11)70156-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Stark D, Barratt JLN, van Hal S, Marriott D, Harkness J, Ellis JT. Clinical significance of enteric protozoa in the immunosuppressed human population. Clin Microbiol Rev 2009; 22:634-50. [PMID: 19822892 PMCID: PMC2772358 DOI: 10.1128/cmr.00017-09] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Globally, the number of immunosuppressed people increases each year, with the human immunodeficiency virus (HIV) pandemic continuing to spread unabated in many parts of the world. Immunosuppression may also occur in malnourished persons, patients undergoing chemotherapy for malignancy, and those receiving immunosuppressive therapy. Components of the immune system can be functionally or genetically abnormal as a result of acquired (e.g., caused by HIV infection, lymphoma, or high-dose steroids or other immunosuppressive medications) or congenital illnesses, with more than 120 congenital immunodeficiencies described to date that either affect humoral immunity or compromise T-cell function. All individuals affected by immunosuppression are at risk of infection by opportunistic parasites (such as the microsporidia) as well as those more commonly associated with gastrointestinal disease (such as Giardia). The outcome of infection by enteric protozoan parasites is dependent on absolute CD4(+) cell counts, with lower counts being associated with more severe disease, more atypical disease, and a greater risk of disseminated disease. This review summarizes our current state of knowledge on the significance of enteric parasitic protozoa as a cause of disease in immunosuppressed persons and also provides guidance on recent advances in diagnosis and therapy for the control of these important parasites.
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Affiliation(s)
- D Stark
- Department of Microbiology, St. Vincent's Hospital, Darlinghurst 2010, NSW, Australia.
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12
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Rivero Z, Bracho A, Calchi M, Díaz I, Acurero E, Maldonado A, Chourio G, Arráiz N, Corzo G. [Detection and differentiation of Entamoeba histolytica and Entamoeba dispar by polymerase chain reaction in a community in Zulia State, Venezuela]. CAD SAUDE PUBLICA 2009; 25:151-9. [PMID: 19180297 DOI: 10.1590/s0102-311x2009000100016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Accepted: 07/01/2008] [Indexed: 11/22/2022] Open
Abstract
Differential identification of Entamoeba histolytica and Entamoeba dispar is essential for both appropriate patient treatment and epidemiological purposes. To determine the prevalence of these amoeba infections in Santa Rosa de Agua (Maracaibo, Zulia State, Venezuela), a PCR assay using specific primers for each species was standardized and applied. 204 stool samples were analyzed through direct microscopic examination with SSF (0.85%) and lugol, formol-ether concentration, and PCR. Under direct microscopy, 42 individuals (20.58%) presented the E. histolytica/E. dispar complex. Meanwhile PCR showed 47 positive cases for these amoebas: 22 E. histolytica (10.78%), 16 E. dispar (7.84%), and 9 (4.41%) mixed infections. There was no significant difference in the presence of E. histolytica and/or E. dispar according to either gender or age. There were no cases of these amoebas in children under 2 years of age. Observed frequency of E. histolytica (31/204) shows the endemic nature of amoeba infection in this community.
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Affiliation(s)
- Zulbey Rivero
- Escuela de Bioanálisis, Universidad del Zulia, Maracaibo, Venezuela.
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Fotedar R, Stark D, Beebe N, Marriott D, Ellis J, Harkness J. Laboratory diagnostic techniques for Entamoeba species. Clin Microbiol Rev 2007; 20:511-32, table of contents. [PMID: 17630338 PMCID: PMC1932757 DOI: 10.1128/cmr.00004-07] [Citation(s) in RCA: 251] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genus Entamoeba contains many species, six of which (Entamoeba histolytica, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba polecki, Entamoeba coli, and Entamoeba hartmanni) reside in the human intestinal lumen. Entamoeba histolytica is the causative agent of amebiasis and is considered a leading parasitic cause of death worldwide in humans. Although recent studies highlight the recovery of E. dispar and E. moshkovskii from patients with gastrointestinal symptoms, there is still no convincing evidence of a causal link between the presence of these two species and the symptoms of the host. New approaches to the identification of E. histolytica are based on detection of E. histolytica-specific antigen and DNA in stool and other clinical samples. Several molecular diagnostic tests, including conventional and real-time PCR, have been developed for the detection and differentiation of E. histolytica, E. dispar, and E. moshkovskii in clinical samples. The purpose of this review is to discuss different methods that exist for the identification of E. histolytica, E. dispar, and E. moshkovskii which are available to the clinical diagnostic laboratory. To address the need for a specific diagnostic test for amebiasis, a substantial amount of work has been carried out over the last decade in different parts of the world. The molecular diagnostic tests are increasingly being used for both clinical and research purposes. In order to minimize undue treatment of individuals infected with other species of Entamoeba such as E. dispar and E. moshkovskii, efforts have been made for specific diagnosis of E. histolytica infection and not to treat based simply on the microscopic examination of Entamoeba species in the stool. The incorporation of many new technologies into the diagnostic laboratory will lead to a better understanding of the public health problem and measures to control the disease.
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Affiliation(s)
- R Fotedar
- St. Vincent's Hospital, Department of Microbiology, Sydney, Darlinghurst, NSW 2010, Australia
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Diagnostic methods for differentiation of Entamoeba histolytica and Entamoeba dispar in carriers: performance and clinical implications in a non-endemic setting. Int J Med Microbiol 2006; 296:397-403. [PMID: 16753339 DOI: 10.1016/j.ijmm.2006.03.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2005] [Revised: 03/14/2006] [Accepted: 03/14/2006] [Indexed: 11/21/2022] Open
Abstract
Unpreserved faecal samples, suspected to contain Entamoeba histolytica/Entamoeba dispar cysts or trophozoites on the basis of microscopic examination, and serum samples from 416 patients were collected in a prospective study to determine whether stool antigen assays and detection of antibodies in serum are reliable methods to distinguish between carriers of E. histolytica and E. dispar in comparison to the reference test: real-time PCR. In 283 patients (68%) DNA of E. histolytica or E. dispar was amplified by real-time PCR: 6 patients with amoebic colitis (2%), 19 carriers of E. histolytica (6.7%), and 258 carriers of E. dispar (91.2%). In 133 patients (31%) no DNA of E. histolytica or E. dispar could be amplified in the stool samples. This patient group was used as control for the evaluation of diagnostic tests. Using real-time PCR as a reference test, the sensitivity and specificity of (1) the Entamoeba test for the diagnosis of E. histolytica/E. dispar carrier were 59% and 98%, (2) E. histolytica II for the diagnosis of E. histolytica carrier was 71% and 100%, and (3) serology for the diagnosis of E. histolytica infection was 83.3% and 95.2%, respectively. Applied to carriers that did not originate from an endemic country the sensitivity of serology for E. histolytica infection was 90% and specificity was 98.8%. In comparison to real-time PCR the performances of Entamoeba test and E. histolytica II lacked sensitivity for a reliable diagnosis of E. histolytica/E. dispar infection in a non-endemic setting. In carriers of E. histolytica/E. dispar from non-endemic countries the high specificity of serology can be used to establish the diagnosis of E. histolytica infection if antibodies are present.
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Silva MCDM, Monteiro CDSP, Araújo BDAV, Silva JV, Póvoa MM. [Determination of Entamoeba histolytica infection in patients from Greater Metropolitan Belém, Para, Brazil, by enzyme-linked immunosorbent assay (ELISA) for antigen detection]. CAD SAUDE PUBLICA 2005; 21:969-73. [PMID: 15868057 DOI: 10.1590/s0102-311x2005000300033] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The epidemiological status of amebiasis has been reevaluated since Entamoeba histolytica (pathogenic) was considered a distinct species from Entamoeba dispar (non-pathogenic). We investigated E. histolytica antigens in stool samples from residents of Belém, Para State, Brazil, with commercially available enzyme-linked immunosorbent assay (E. histolytica Test, TechLab Inc., Blacksburg, USA). A total of 845 samples were analyzed, of which 248 were positive (29.35%). E. histolytica infection was more frequent in the over-14-year age group (30.36%) than in the 0-14-year group (28.28%), but the difference was not statistically significant (p < 0.05). Of all the samples, 334 were also submitted to parasitological methods (direct, Hoffman, and Faust et al.). There were discordant results between ELISA and parasitological methods in 83 samples (24.85%), with more positive results using ELISA. Our results thus suggest that intestinal amebiasis is an important public health problem in Greater Metropolitan Belém.
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Roy S, Kabir M, Mondal D, Ali IKM, Petri WA, Haque R. Real-time-PCR assay for diagnosis of Entamoeba histolytica infection. J Clin Microbiol 2005; 43:2168-72. [PMID: 15872237 PMCID: PMC1153781 DOI: 10.1128/jcm.43.5.2168-2172.2005] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Revised: 11/08/2004] [Accepted: 12/20/2004] [Indexed: 11/20/2022] Open
Abstract
We developed a real-time-PCR assay utilizing a molecular-beacon probe for the detection of Entamoeba histolytica and compared its sensitivity to stool antigen detection and traditional PCR. A total of 205 stool and liver abscess pus specimens from patients and controls were used for this purpose, 101 (49%) of which were positive by the TechLab E. histolytica-specific antigen detection test, while the other 104 (51%) stool and liver abscess pus specimens were negative by the antigen detection test. DNA was extracted from the stool and liver abscess pus specimens by the QIAGEN method and the small-subunit rRNA gene of E. histolytica and then amplified by traditional and real-time PCR. Out of these 205 stool and liver abscess pus specimens, 124 were positive by the real-time-PCR assay and 90 were positive by the traditional-PCR test. Compared to the real-time-PCR assay, the antigen detection test was 79% sensitive and 96% specific. When the traditional-PCR test results were compared to the real-time-PCR assay, the sensitivity of traditional PCR was 72% and the specificity was 99%. In conclusion, all three methods for the detection of E. histolytica were highly specific, with real-time PCR being the most sensitive.
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Affiliation(s)
- Shantanu Roy
- International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,b), Dhaka, Bangladesh
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Affiliation(s)
- Rashidul Haque
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
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Abstract
Amoebiasis is the second leading cause of death from parasitic disease worldwide. The causative protozoan parasite, Entamoeba histolytica, is a potent pathogen. Secreting proteinases that dissolve host tissues, killing host cells on contact, and engulfing red blood cells, E histolytica trophozoites invade the intestinal mucosa, causing amoebic colitis. In some cases amoebas breach the mucosal barrier and travel through the portal circulation to the liver, where they cause abscesses consisting of a few E histolytica trophozoites surrounding dead and dying hepatocytes and liquefied cellular debris. Amoebic liver abscesses grow inexorably and, at one time, were almost always fatal, but now even large abscesses can be cured by one dose of antibiotic. Evidence that what we thought was a single species based on morphology is, in fact, two genetically distinct species--now termed Entamoeba histolytica (the pathogen) and Entamoeba dispar (a commensal)--has turned conventional wisdom about the epidemiology and diagnosis of amoebiasis upside down. New models of disease have linked E histolytica induction of intestinal inflammation and hepatocyte programmed cell death to the pathogenesis of amoebic colitis and amoebic liver abscess.
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Affiliation(s)
- Samuel L Stanley
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, St Louis, MO 63110, USA.
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The diagnostic implications of the separation ofEntamoeba histolytica andEntamoeba dispar. J Biosci 2002. [DOI: 10.1007/bf02704850] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
It is an exciting time in the study of Entamoeba histolytica. Over the past two years, the natural history and burden of disease in humans has been redefined, mucosal immune responses associated with protection identified, and the developmental regulation of encystation outlined. The number of genes sequenced has increased from a few hundred to a few thousand, and study of the genome structure is revealing unusual repetitive elements and plasticity. DNA microarrays promise the first ability to examine global patterns of mRNA abundance. The mechanism of transcriptional control via histone modifications and sequence-specific DNA-binding proteins are to be delineated. Advances in cell biology are providing new insights into invasion through the intestinal epithelium.
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Affiliation(s)
- William A Petri
- Division of Infectious Diseases, Room 2115, MR4 Building, Lane Road, PO Box 801340, University of Virginia Health System, Charlottesville, Virginia 22908-1340, USA.
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