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Abstract
Microsporidia are obligate intracellular pathogens identified ∼150 years ago as the cause of pébrine, an economically important infection in silkworms. There are about 220 genera and 1,700 species of microsporidia, which are classified based on their ultrastructural features, developmental cycle, host-parasite relationship, and molecular analysis. Phylogenetic analysis suggests that microsporidia are related to the fungi, being grouped with the Cryptomycota as a basal branch or sister group to the fungi. Microsporidia can be transmitted by food and water and are likely zoonotic, as they parasitize a wide range of invertebrate and vertebrate hosts. Infection in humans occurs in both immunocompetent and immunodeficient hosts, e.g., in patients with organ transplantation, patients with advanced human immunodeficiency virus (HIV) infection, and patients receiving immune modulatory therapy such as anti-tumor necrosis factor alpha antibody. Clusters of infections due to latent infection in transplanted organs have also been demonstrated. Gastrointestinal infection is the most common manifestation; however, microsporidia can infect virtually any organ system, and infection has resulted in keratitis, myositis, cholecystitis, sinusitis, and encephalitis. Both albendazole and fumagillin have efficacy for the treatment of various species of microsporidia; however, albendazole has limited efficacy for the treatment of Enterocytozoon bieneusi. In addition, immune restoration can lead to resolution of infection. While the prevalence rate of microsporidiosis in patients with AIDS has fallen in the United States, due to the widespread use of combination antiretroviral therapy (cART), infection continues to occur throughout the world and is still seen in the United States in the setting of cART if a low CD4 count persists.
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Li W, Feng Y, Xiao L. Diagnosis and molecular typing of Enterocytozoon bieneusi: the significant role of domestic animals in transmission of human microsporidiosis. Res Vet Sci 2020; 133:251-261. [PMID: 33035931 DOI: 10.1016/j.rvsc.2020.09.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 09/15/2020] [Accepted: 09/25/2020] [Indexed: 12/30/2022]
Abstract
Enterocytozoon bieneusi is an obligate intracellular fungus-like parasite with high genetic diversity among mammalian and avian hosts. Based on polymorphism analysis of the ribosomal internal transcribed spacer (ITS), nearly 500 genotypes were identified within E. bieneusi. Those genotypes form several genetic groups that exhibit phenotypic differences in host specificity and zoonotic potential and probably have varying public health implications. Some of the genotypes in Group 1 (e.g., D, EbpC, and Type IV) and Group 2 (e.g., BEB4, BEB6, I, and J) are the most common ones that infect a variety of hosts including humans and thus are of public health importance. By contrast, those genotypes in other genetic groups (Groups 3-11) are mostly restricted to the hosts from which they were originally isolated, which would have unknown or limited impacts on public health. Advances on diagnosis and molecular typing of E. bieneusi are introduced in this review. Genotype distribution pattern of E. bieneusi in major domestic animal groups (pigs, cattle, sheep, goats, cats, and dogs), the role of those animals in zoonotic transmission of microsporidiosis, and food and water as potential vehicles for transmission are interpreted here as well. This review highlights the importance of including more genetic or epidemiological data obtained in the same geographical areas and using more reliable genetic markers to analyze the actual extent of host specificity in E. bieneusi, for the purpose of fully appreciating zoonotic risks of those domestic animals in close contacts with men and enhancing our understanding of the modes of transmission.
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Affiliation(s)
- Wei Li
- Heilongjiang Key Laboratory for Zoonosis, College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang, China.
| | - Yaoyu Feng
- Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China
| | - Lihua Xiao
- Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong, China.
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Abstract
INTRODUCTION Microsporidia have been increasingly reported to infect humans. The most common presentation of microsporidiosis is chronic diarrhea, a significant mortality risk in immune-compromised patients. Albendazole, which inhibits tubulin, and fumagillin, which inhibits methionine aminopeptidase type 2 (MetAP2), are the two main therapeutic agents used for treatment of microsporidiosis. In addition, to their role as emerging pathogens in humans, microsporidia are important pathogens in insects, aquaculture, and veterinary medicine. New therapeutic targets and therapies have become a recent focus of attention for medicine, veterinary, and agricultural use. Areas covered: Herein, we discuss the detection and symptoms of microsporidiosis in humans and the therapeutic targets that have been utilized for the design of new drugs for the treatment of this infection, including triosephosphate isomerase, tubulin, MetAP2, topoisomerase IV, chitin synthases, and polyamines. Expert opinion: Enterocytozoon bieneusi is the most common microsporidia in human infection. Fumagillin has a broader anti-microsporidian activity than albendazole and is active against both Ent. bieneusi and Encephaliozoonidae. Microsporidia lack methionine aminopeptidase type 1 and are, therefore, dependent on MetAP2, while mammalian cells have both enzymes. Thus, MetAP2 is an essential enzyme in microsporidia and new inhibitors of this pathway have significant promise as therapeutic agents.
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Affiliation(s)
- Bing Han
- Department of Pathology, Division of Tropical Medicine and Parasitology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Louis M. Weiss
- Department of Pathology, Division of Tropical Medicine and Parasitology, Albert Einstein College of Medicine, Bronx, NY 10461
- Department of Medicine, Division of Infectious Diseases, Albert Einstein College of Medicine, Bronx, NY 10461
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Molecular diagnostic tests for microsporidia. Interdiscip Perspect Infect Dis 2009; 2009:926521. [PMID: 19657457 PMCID: PMC2719812 DOI: 10.1155/2009/926521] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 05/12/2009] [Indexed: 11/29/2022] Open
Abstract
The Microsporidia are a ubiquitous group of eukaryotic obligate intracellular parasites which were recognized over 100 years ago with the description of Nosema bombycis, a parasite of silkworms. It is now appreciated that these organisms are related to the Fungi. Microsporidia infect all major animal groups most often as gastrointestinal pathogens; however they have been reported from every tissue and organ, and their spores are common in environmental sources such as ditch water. Several different genera of these organisms infect humans, but the majority of infections are due to either
Enterocytozoon bieneusi or Encephalitozoon species. These pathogens can be difficult to diagnose, but significant progress has been made in the last decade in the development of molecular diagnostic reagents for these organisms. This report reviews the molecular diagnostic tests that have been described for the identification of the microsporidia that infect humans.
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Graczyk TK, Kacprzak M, Neczaj E, Tamang L, Graczyk H, Lucy FE, Girouard AS. Human-virulent microsporidian spores in solid waste landfill leachate and sewage sludge, and effects of sanitization treatments on their inactivation. Parasitol Res 2007; 101:569-75. [PMID: 17364164 DOI: 10.1007/s00436-007-0515-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Accepted: 03/04/2007] [Indexed: 11/25/2022]
Abstract
Solid waste landfill leachate and sewage sludge samples were quantitatively tested for viable Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon hellem, and Encephalitozoon cuniculi spores by the multiplexed fluorescence in situ hybridization (FISH) assay. The landfill leachate samples tested positive for E. bieneusi and the sludge samples for E. bieneusi and E. intestinalis. The effects of four sanitization treatments on the inactivation of these pathogens were assessed. Depending on the variations utilized in the ultrasound disintegration, sonication reduced the load of human-virulent microsporidian spores to nondetectable levels in 19 out of 27 samples (70.4%). Quicklime stabilization was 100% effective, whereas microwave energy disintegration was 100% ineffective against the spores of E. bieneusi and E. intestinalis. Top-soil stabilization treatment gradually reduced the load of both pathogens, consistent with the serial dilution of sewage sludge with the soil substrate. This study demonstrated that sewage sludge and landfill leachate contained high numbers of viable, human-virulent microsporidian spores, and that sonication and quicklime stabilization were the most effective treatments for the sanitization of sewage sludge and solid waste landfill leachates. Multiplexed FISH assay is a reliable quantitative molecular fluorescence microscopy method for the simultaneous identification of E. bieneusi, E. intestinalis, E. hellem, and E. cuniculi spores in environmental samples.
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Affiliation(s)
- Thaddeus K Graczyk
- Department of Environmental Health Sciences, Division of Environmental Health Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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Graczyk TK, Johansson MA, Tamang L, Visvesvara GS, Moura LS, DaSilva AJ, Girouard AS, Matos O. Retrospective species identification of microsporidian spores in diarrheic fecal samples from human immunodeficiency virus/AIDS patients by multiplexed fluorescence in situ hybridization. J Clin Microbiol 2007; 45:1255-60. [PMID: 17287331 PMCID: PMC1865804 DOI: 10.1128/jcm.01975-06] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to assess the applicability of multiplexed fluorescence in situ hybridization (FISH) assay for the clinical setting, we conducted retrospective analysis of 110 formalin-stored diarrheic stool samples from human immunodeficiency virus (HIV)/AIDS patients with intestinal microsporidiosis collected between 1992 and 2003. The multiplexed FISH assay identified microsporidian spores in 94 of 110 (85.5%) samples: 49 (52.1%) were positive for Enterocytozoon bieneusi, 43 (45.8%) were positive for Encephalitozoon intestinalis, 2 (2.1%) were positive for Encephalitozoon hellem, and 9 samples (9.6%) contained both E. bieneusi and E. intestinalis spores. Quantitative spore counts per ml of stool yielded concentration values from 3.5 x 10(3) to 4.4 x 10(5) for E. bieneusi (mean, 8.8 x 10(4)/ml), 2.3 x 10(2) to 7.8 x 10(4) (mean, 1.5 x 10(4)/ml) for E. intestinalis, and 1.8 x 10(2) to 3.6 x 10(2) for E. hellem (mean, 2.7 x 10(2)/ml). Identification of microsporidian spores by multiplex FISH assay was more sensitive than both Chromotrope-2R and CalcoFluor White M2R stains; 85.5% versus 72.7 and 70.9%, respectively. The study demonstrated that microsporidian coinfection in HIV/AIDS patients with intestinal microsporidiosis is not uncommon and that formalin-stored fecal samples older than 10 years may not be suitable for retrospective analysis by techniques targeting rRNA. Multiplexed FISH assay is a reliable, quantitative fluorescence microscopy method for the simultaneous identification of E. bieneusi, E. intestinalis, and E. hellem, as well as Encephalitozoon cuniculi, spores in fecal samples and is a useful tool for assessing spore shedding intensity in intestinal microsporidiosis. The method can be used for epidemiological investigations and applied in clinical settings.
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Affiliation(s)
- Thaddeus K Graczyk
- Department of Environmental Health Sciences, Division of Environmental Health Engineering, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA.
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Wang Z, Orlandi PA, Stenger DA. Simultaneous detection of four human pathogenic microsporidian species from clinical samples by oligonucleotide microarray. J Clin Microbiol 2005; 43:4121-8. [PMID: 16081959 PMCID: PMC1233985 DOI: 10.1128/jcm.43.8.4121-4128.2005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Microsporidian species have been rapidly emerging as human enteric pathogens in immunocompromised and immunocompetent individuals in recent years. Routine diagnostic techniques for microsporidia in clinical laboratories are laborious and insensitive and tend to underestimate their presence. In most instances, they are unable to differentiate species of spores due to their small sizes and similar morphologies. In this study, we report the development of another protozoan oligonucleotide microarray assay for the simultaneous detection and identification to the species level of four major microsporidian species: Enterocytozoon bieneusi, Encephalitozoon cuniculi, Encephalitozoon hellem, and Encephalitozoon intestinalis. The 18S small-subunit rRNA gene was chosen as the amplification target, labeled with fluorescence dye, and hybridized to a series of species-specific oligonucleotide probes immobilized on a microchip. The specificity and sensitivity of the microarray were clearly demonstrated by the unique hybridization profiles exhibited by each species of microsporidian tested and its ability to detect as few as 10 spores. In order to assess the applicability of this microarray in a clinical setting, we conducted microarray assays of 20 fecal samples from AIDS patients. Twelve of these samples were positive for the presence of microsporidia and could be confidently identified; 11 of them were positive for more than one species. Our results suggested that this microarray-based approach represents an attractive diagnostic tool for high-throughput detection and identification of microsporidian species in clinical and epidemiological investigations.
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Affiliation(s)
- Zheng Wang
- Center for Bio/Molecular Science and Engineering, Code 6910, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, USA.
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Velásquez JN, Carnevale S, Oelemann WMR, Etchart C, Peralta JM. Diagnosis of Enterocytozoon bieneusi by the polymerase chain reaction in archival fixed duodenal tissue. Enferm Infecc Microbiol Clin 2005; 23:218-20. [PMID: 15826547 DOI: 10.1157/13073148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study involved ninety five formalin-fixed paraffin-embedded duodenal biopsy specimens retrieved from hospital files that were microscopically observed for the presence of microsporidia. Eleven samples that revealed compatible organisms were analyzed by the polymerase chain reaction (PCR) with four different protocols for the detection of Enterocytozoon bieneusi. Amplicons of the right size were obtained by at least one method for nine samples, remaining two negative ones. We report a PCR methodology that allows the use of archival specimens obtained for traditional pathology.
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Affiliation(s)
- Jorge N Velásquez
- Hospital Municipal de Infecciosas Dr. Francisco Javier Muñiz, Buenos Aires, Argentina.
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Buckholt MA, Lee JH, Tzipori S. Prevalence of Enterocytozoon bieneusi in swine: an 18-month survey at a slaughterhouse in Massachusetts. Appl Environ Microbiol 2002; 68:2595-9. [PMID: 11976142 PMCID: PMC127518 DOI: 10.1128/aem.68.5.2595-2599.2002] [Citation(s) in RCA: 245] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Slaughterhouse pig samples were analyzed by PCR for Enterocytozoon bieneusi infection. Thirty-two percent were found to be positive, with rates being higher over the summer months. Three isolates from pigs were identical in their ribosomal internal transcribed spacer sequence to human E. bieneusi type D, two were identical to type F (from a pig), and nine were previously unreported. The viability of these spores was demonstrated by their ability to infect gnotobiotic piglets. The presence of the infection in liver was shown by in situ hybridization.
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Affiliation(s)
- Michael A Buckholt
- Division of Infectious Diseases, Department of Biomedical Sciences, Tufts University School of Veterinary Medicine, North Grafton, Massachusetts 01536, USA
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Brown AMV, Kent ML. Molecular Diagnostics for Loma Salmonae and Nucleospora Salmonis (Microsporidia). REVIEWS: METHODS AND TECHNOLOGIES IN FISH BIOLOGY AND FISHERIES 2002. [DOI: 10.1007/978-94-017-2315-2_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Sánchez JG, Speare DJ, Markham RJ, Wright GM, Kibenge FS. Localization of the initial developmental stages of Loma salmonae in rainbow trout (Oncorhynchus mykiss). Vet Pathol 2001; 38:540-6. [PMID: 11572561 DOI: 10.1354/vp.38-5-540] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The intracellular microsporidian parasite Loma salmonae affects salmonids of the genus Oncorhynchus and is a significant cause of economic losses in pen-reared Chinook salmon (O. tshawytscha) in British Columbia. Loma salmonae infection is easily recognized by the xenomas that form in the gills, but early stages of infection are difficult to detect in histologic sections. In situ hybridization (ISH), using an L. salmonae-specific digoxigenin-labeled single-stranded DNA probe, was used to detect the parasite during the early stages of infection. Loma salmonae was detected in the gut mucosal epithelium as early as 24 hours postexposure (PE), and it localized in the lamina propria of the intestine within 24 hours of infection. After the parasite was detected in the lamina propria, dividing merogonic stages in infected cells in the heart were detected by ISH as early as 2 days PE, providing the first evidence of parasitaemia and hematogenous distribution of this parasite in infected blood cells. The parasites inside the infected cells appeared to be undergoing merogony as they passed through the heart, indicating that proliferation may start at the site of infection, before the parasite arrives to the gills for their final developmental phase. This is the first time that L. salmonae passage through the intestinal wall and migration to the heart has been visualized; however, the identity of the cells harboring the parasite has yet to be determined.
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Affiliation(s)
- J G Sánchez
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Canada
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Abstract
Microsporidia are considered opportunistic pathogens in humans because they are most likely to cause diseases if the immune status of a host is such that the infection cannot be controlled. A wide spectrum of diseases has been reported among persons infected with microsporidia and different diagnostic techniques have been developed during the last decade.
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Affiliation(s)
- C Franzen
- Department of Internal Medicine I, University of Cologne, Joseph Stelzmann Str. 9, 50924, Cologne, Germany.
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Chalifoux LV, Carville A, Pauley D, Thompson B, Lackner AA, Mansfield KG. Enterocytozoon bieneusi as a cause of proliferative serositis in simian immunodeficiency virus-infected immunodeficient macaques (Macaca mulatta). Arch Pathol Lab Med 2000; 124:1480-4. [PMID: 11035580 DOI: 10.5858/2000-124-1480-ebaaco] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT Enterocytozoon bieneusi is the most frequent microsporidian parasite of human patients with acquired immunodeficiency syndrome and is a significant cause of diarrhea and wasting. Recently, this organism has also been recognized as a spontaneous infection of several species of captive macaques. As in humans, E bieneusi frequently causes enteropathy and cholangiohepatitis in immunodeficient simian immunodeficiency virus (SIV)-infected macaques. OBJECTIVE To examine E bieneusi as an etiologic agent of nonsuppurative proliferative serositis in immunodeficient rhesus macaques (Macaca mulatta). DESIGN Retrospective analysis of necropsy material obtained from immunodeficient SIV-infected rhesus macaques. RESULTS Examination of SIV-infected rhesus macaques (n = 225) revealed E bieneusi proliferative serositis in 7 of 16 cases of peritonitis of unknown origin. The organism could be identified by in situ hybridization and polymerase chain reaction in sections of pleura and peritoneum obtained at necropsy. Serositis was always accompanied by moderate-to-severe infection of the alimentary tract, and morphologic evidence suggested dissemination through efferent lymphatics. Colabeling experiments revealed most infected cells to be cytokeratin positive and less frequently positive for the macrophage marker CD68. Sequencing of a 607-base pair segment of the small subunit ribosomal gene revealed 100% identity to sequences obtained from rhesus macaques (Genbank accession AF023245) and human patients (Genbank accession AF024657 and L16868). CONCLUSIONS These findings indicate that E bieneusi disseminates in immunodeficient macaques and may be a cause of peritonitis in the immunocompromised host.
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Affiliation(s)
- L V Chalifoux
- New England Regional Primate Research Center, Harvard Medical School, One Pine Hill Dr, Southborough, MA 01772-9012, USA
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Abstract
Infectious diseases of the gastrointestinal tract continue to be an important source of morbidity and mortality. Viruses, bacteria, fungi, and protozoa that infect normal hosts also infect the gastrointestinal tract in immunocompromised hosts. Disease caused by these pathogens may be more severe and more difficult to treat in immunocompromised hosts. In addition, pathogens that rarely cause disease in normal hosts cause significant disease in immunosuppressed hosts. Diagnostic decisions need to take into account expected pathogens and response to therapy. Treatment decisions must be based on the findings of diagnostic procedures; expected pathogens; and recent data suggesting that highly active antiretroviral therapy, with its ability to reconstitute immune function, is an essential component of treatment. This review summarizes the most important developments made in the pathogenesis, clinical presentation, diagnosis, and treatment of gastrointestinal infections in immunocompromised hosts in the past year.
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Affiliation(s)
- L Fantry
- University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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