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Chala B. Advances in Diagnosis of Schistosomiasis: Focus on Challenges and Future Approaches. Int J Gen Med 2023; 16:983-995. [PMID: 36967838 PMCID: PMC10032164 DOI: 10.2147/ijgm.s391017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/07/2023] [Indexed: 03/20/2023] Open
Abstract
Schistosomiasis is the second most devastating parasite prevalent in the tropical region of the world, posing significant public health impacts in endemic areas. Presently, several disease mitigation measures have shown a decline in transmission of the infection rate in risk localities using mass drug administration (MDA) of school-based or community-wide treatments. Despite all the endeavors made, the decline in transmission of infection rate has not been attained in the entire medicated segment of the population. Perhaps the current challenges of control of the disease appear to be strongly associated with a lack of appropriate diagnostic tools. It's well known that the current diagnosis of schistosomiasis greatly relies on conventional methods. On the other hand, minor symptoms of schistosomiasis and low sensitivity and specificity of diagnostic methods are still unresolved diagnostic challenges to clinicians. Numerous scholars have reviewed various diagnostic methods of schistosomiasis and attempted to identify their strengths and weaknesses, currently on function. As a result of the known limitations of the existing diagnostic tools, the need to develop new and feasible diagnostic methods and diagnostic markers is unquestionable for more precise detection of the infection. Hence, advances in diagnostic methods have been considered part of the solution for the control and eventual elimination strategy of the disease in endemic areas. As of today, easy, cheap, and accurate diagnostics for schistosomiasis are difficult to get, and this limits the concerted efforts towards full control of schistosomiasis. While looking for new diagnostic methods and markers, it is important to simultaneously work on improving the existing diagnostic methods for better results. This review tries to give new insights to the status of the existing diagnostic methods of schistosomiasis from conventional to modern via summarizing the strengths and limitations of the methods. It also tries to recommend new, sensitive and feasible diagnostic methods for future approaches.
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Affiliation(s)
- Bayissa Chala
- Department of Applied Biology, School of Applied Natural Science, Adama Science and Technology University, Adama, Ethiopia
- Correspondence: Bayissa Chala, Email ;
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2
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Lynch AE, Noble LR, Jones CS, Routledge EJ. Common aquatic pollutants modify hemocyte immune responses in Biomphalaria glabrata. Front Immunol 2022; 13:839746. [PMID: 36159819 PMCID: PMC9493456 DOI: 10.3389/fimmu.2022.839746] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 08/23/2022] [Indexed: 11/13/2022] Open
Abstract
Disruptions to reproductive health in wildlife species inhabiting polluted environments is often found to occur alongside compromised immunity. However, research on impacts of aquatic pollution on freshwater mollusc immune responses is limited despite their importance as vectors of disease (Schistosomiasis) in humans, cattle and wild mammals. We developed an in vitro ‘tool-kit’ of well-characterized quantitative immune tests using Biomphalaria glabrata hemocytes. We exposed hemocytes to environmentally-relevant concentrations of common aquatic pollutants (17β-estradiol, Bisphenol-A and p,p’-DDE) and measured key innate immune responses including motility, phagocytosis and encapsulation. Additionally, we tested an extract of a typical domestic tertiary treated effluent as representative of a ‘real-world’ mixture of chemicals. Encapsulation responses were stimulated by p,p’-DDE at low doses but were suppressed at higher doses. Concentrations of BPA (above 200 ng/L) and p,p’-DDE (above 500 ng/L) significantly inhibited phagocytosis compared to controls, whilst hemocyte motility was reduced by all test chemicals and the effluent extract in a dose-dependent manner. All responses occurred at chemical concentrations considered to be below the cytotoxic thresholds of hemocytes. This is the first time a suite of in vitro tests has been developed specifically in B. glabrata with the purpose of investigating the impacts of chemical pollutants and an effluent extract on immunity. Our findings indicate that common aquatic pollutants alter innate immune responses in B. glabrata, suggesting that pollutants may be a critical, yet overlooked, factor impacting disease by modulating the dynamics of parasite transmission between molluscs and humans.
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Affiliation(s)
- Adam E. Lynch
- College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Leslie R. Noble
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
- School of Biological Sciences, Aberdeen University, Aberdeen, United Kingdom
| | - Catherine S. Jones
- School of Biological Sciences, Aberdeen University, Aberdeen, United Kingdom
| | - Edwin J. Routledge
- College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, United Kingdom
- *Correspondence: Edwin J. Routledge,
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3
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Wanlop A, Dang-Trinh MA, Kirinoki M, Suguta S, Shinozaki K, Kawazu SI. A simple and efficient miracidium hatching technique for preparing a single-genome DNA sample of Schistosoma japonicum. J Vet Med Sci 2022; 84:1108-1110. [PMID: 35732429 PMCID: PMC9412067 DOI: 10.1292/jvms.21-0536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, a simple and efficient miracidium hatching technique (MHT) protocol for
preparing a single-genome DNA of Schistosoma japonicum was proposed. The
protocol was designed with 96-well plates to collect a miracidium for single-genome DNA
preparation, and the effects of lighting conditions on hatching rates were evaluated. The
highest hatching rate was recorded under sunlight (92.4%), followed by fluorescent light
(88.0%), and the lowest rate was recorded under the dark condition (4.7%). The results
suggested for the first time, to our knowledge, that sunlight was efficient for this
simple MHT protocol. Successful amplification of microsatellite marker genes using DNA
isolated from a single miracidium also confirmed the quality of the single-genome DNA for
subsequent applications.
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Affiliation(s)
- Atcharaphan Wanlop
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine
| | | | - Masashi Kirinoki
- Department of Tropical Medicine and Parasitology, Dokkyo Medical University
| | - Saki Suguta
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine
| | - Kaho Shinozaki
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine
| | - Shin-Ichiro Kawazu
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine
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Perera DJ, Hassan AS, Jia Y, Ricciardi A, McCluskie MJ, Weeratna RD, Ndao M. Adjuvanted Schistosoma mansoni-Cathepsin B With Sulfated Lactosyl Archaeol Archaeosomes or AddaVax™ Provides Protection in a Pre-Clinical Schistosomiasis Model. Front Immunol 2020; 11:605288. [PMID: 33304354 PMCID: PMC7701121 DOI: 10.3389/fimmu.2020.605288] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/20/2020] [Indexed: 12/15/2022] Open
Abstract
Schistosomiasis threatens 800 million people worldwide. Chronic pathology manifests as hepatosplenomegaly, and intestinal schistosomiasis caused by Schistosoma mansoni can lead to liver fibrosis, cirrhosis, and blood in the stool. To assist the only FDA-approved drug, praziquantel, in parasite elimination, the development of a vaccine would be of high value. S. mansoni Cathepsin B (SmCB) is a well-documented vaccine target for intestinal schistosomiasis. Herein, we test the increased efficacy and immunogenicity of SmCB when combined with sulfated lactosyl archaeol (SLA) archaeosomes or AddaVax™ (a squalene based oil-in-water emulsion). Both vaccine formulations resulted in robust humoral and cell mediated immune responses. Impressively, both formulations were able to reduce parasite burden greater than 40% (WHO standard), with AddaVax™ reaching 86.8%. Additionally, SmCB with both adjuvants were able to reduce granuloma size and the amount of larval parasite hatched from feces, which would reduce transmission. Our data support SmCB as a target for S. mansoni vaccination; especially when used in an adjuvanted formulation.
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Affiliation(s)
- Dilhan J Perera
- Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, QC, Canada.,Infectious Diseases and Immunity in Global Health Program, The Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Adam S Hassan
- Infectious Diseases and Immunity in Global Health Program, The Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Yimei Jia
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, ON, Canada
| | - Alessandra Ricciardi
- Infectious Diseases and Immunity in Global Health Program, The Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Michael J McCluskie
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, ON, Canada
| | - Risini D Weeratna
- Human Health Therapeutics Research Centre, National Research Council Canada, Ottawa, ON, Canada
| | - Momar Ndao
- Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, QC, Canada.,Infectious Diseases and Immunity in Global Health Program, The Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.,National Reference Center for Parasitology, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
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5
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Shen Y, Ji R, Yang M, Lin J, Wang H, Zhu C, Xu Q. Establishment of a fluorescence staining method for Schistosoma japonicum miracidia. Sci Rep 2020; 10:16766. [PMID: 33028866 PMCID: PMC7542450 DOI: 10.1038/s41598-020-73526-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/16/2020] [Indexed: 11/09/2022] Open
Abstract
Currently the diagnosis of schistosomiasis is mainly determined by observing the presence of eggs in host stool samples. Because of the overwhelming number of impurities in the stool, eggs are rarely observed. Therefore, the stool hatching method is used to observe the miracidia in the water. However, the miracidia of Schistosoma japonicum are small and difficult to detect, and missed detection is likely to occur when the infection level is low. In this study, recombinant streptococcal protein G-enhanced green fluorescent protein (rSPG-EGFP) was expressed, purified, and used as a fluorescence staining reagent for miracidia. A preliminary miracidium fluorescence staining method based on antigen and antibody bindingwas established by combining recombinant protein staining with the stool hatching method. The stool hatching method was used to collect the miracidia of S. japonicum, and Schistosoma-positive serum and the recombinant protein were mixed to assess the feasibility of fluorescence staining of miracidia. The miracidia of S. japonicum and Schistosoma turkestanicum were incubated with S. japonicum-positive serum and S. turkestanicum-positive serum, respectively, to identify miracidia species. When the fluorescence staining method was used to observe living miracidia, the miracidiawere labelled by the recombinant protein, and their motility status was not affected.
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Affiliation(s)
- Yuanxi Shen
- Key Laboratory of Animal Parasitology, Ministry of Agricultμre of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Min Hang District, Shanghai, 200241, China
| | - Rongyi Ji
- Key Laboratory of Animal Parasitology, Ministry of Agricultμre of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Min Hang District, Shanghai, 200241, China
- Henry Fok College of Biology and Agriculture, Shaoguan University, No. 288, University Road, Zhenjiang District, Shaoguan City, Guangdong Province, China
| | - Man Yang
- Key Laboratory of Animal Parasitology, Ministry of Agricultμre of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Min Hang District, Shanghai, 200241, China
| | - Jiaojiao Lin
- Key Laboratory of Animal Parasitology, Ministry of Agricultμre of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Min Hang District, Shanghai, 200241, China
| | - Hairong Wang
- Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Road, Tai'an City, 271018, Shandong Province, China
| | - Chuangang Zhu
- Key Laboratory of Animal Parasitology, Ministry of Agricultμre of China, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Min Hang District, Shanghai, 200241, China.
| | - Qinkun Xu
- Henry Fok College of Biology and Agriculture, Shaoguan University, No. 288, University Road, Zhenjiang District, Shaoguan City, Guangdong Province, China.
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Budiono NG, Murtini S, Satrija F, Ridwan Y, Handharyani E. Humoral responses to Schistosoma japonicum soluble egg antigens in domestic animals in Lindu Subdistrict, Central Sulawesi Province, Indonesia. INTERNATIONAL JOURNAL OF ONE HEALTH 2020. [DOI: 10.14202/ijoh.2020.99-108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background and Aim: Schistosomiasis japonica, a disease caused by Schistosoma japonicum, is a public health problem in the Philippines, the Republic of Indonesia, and the People's Republic of China. The disease is known as zoonotic, meaning other than humans, animals are involved as the reservoirs. In Indonesia, schistosomiasis surveillance in animals is not continuous. Thus, the study to determine the prevalence of the disease in animals is needed. The study was aimed to determine the seroprevalence of S. japonicum infection among four species of domestic animals in the Lindu Sub-district, Central Sulawesi Province of Indonesia.
Materials and Methods: Blood samples of domestic animals were collected and analyzed for the presence of anti-S. japonicum immunoglobulin G antibodies against S. japonicum soluble egg antigens using the indirect hemagglutination assay. Animal stool samples were collected, and the miracidia-hatching assay was used for the detection of S. japonicum infection. Additional data concerning the animal identity and the management practices were obtained through a questionnaire used in surveys and interviews.
Results: A total of 146 sera from 13 cattle, 24 buffaloes, 54 pigs, and 55 dogs were collected. The overall schistosomiasis seroprevalence was 64.4%. The serology prevalence in cattle, buffalo, pig, and dog was 100.0%, 41.7%, 74.1%, and 56.4%, respectively. Domestic animals in all of five villages have previous exposure with S. japonicum as seropositive animals detected in every village. A total of 104 animal stool samples from 146 animals sampled were obtained. The overall schistosomiasis prevalence determined by the miracidia hatching assay was 16.35%. The sensitivity and specificity of indirect hemagglutination assay (IHA) in the current study were 88.24% and 41.37%, respectively, with miracidia hatching assay as the gold-standard method.
Conclusion: This study has shown a high seroprevalence of schistosomiasis japonica among domestic animals in the Lindu Subdistrict. IHA can be used as the screening method for the detection of S. japonicum infection in domestic animals. Chemotherapy and animal livestock grazing management programs to reduce the parasite burden and Schistosoma egg contamination in the environment must be implemented as part of one health approaches, in addition to other control measures.
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Affiliation(s)
- Novericko Ginger Budiono
- Parasitology and Medical Entomology Study Program, Graduate School, IPB University, Bogor, Indonesia
| | - Sri Murtini
- Parasitology and Medical Entomology Study Program, Graduate School, IPB University, Bogor, Indonesia; Department of Animal Infectious Diseases and Veterinary Public Health, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia
| | - Fadjar Satrija
- Parasitology and Medical Entomology Study Program, Graduate School, IPB University, Bogor, Indonesia; Department of Animal Infectious Diseases and Veterinary Public Health, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia
| | - Yusuf Ridwan
- Parasitology and Medical Entomology Study Program, Graduate School, IPB University, Bogor, Indonesia; Department of Animal Infectious Diseases and Veterinary Public Health, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia
| | - Ekowati Handharyani
- Department of Veterinary Clinics, Reproduction, and Pathology, Faculty of Veterinary Medicine, IPB University, Bogor, Indonesia
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Nigo MM, Salieb-Beugelaar G, Battegay M, Odermatt P, Hunziker P. Schistosomiasis: from established diagnostic assays to emerging micro/nanotechnology-based rapid field testing for clinical management and epidemiology. PRECISION NANOMEDICINE 2019. [DOI: 10.33218/prnano3(1).191205.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Schistosomiasis is a neglected invasive worm disease with a huge disease burden in developing countries, particularly in children, and is seen increasingly in non-endemic regions through transfer by travellers, expatriates, and refugees. Undetected and untreated infections may be responsible for the persistence of transmission. Rapid and accurate diagnosis is the key to treatment and control. So far, parasitological detection methods remain the cornerstone of Schistosoma infection diagnosis in endemic regions, but conventional tests have limited sensitivity, in particular in low-grade infection. Recent advances contribute to improved detection in clinical and field settings. The recent progress in micro- and nanotechnologies opens a road by enabling the design of new miniaturized point-of-care devices and analytical platforms, which can be used for the rapid detection of these infections. This review starts with an overview of currently available laboratory tests and their performance and then discusses emerging rapid and micro/nanotechnologies-based tools. The epidemiological and clinical setting of testing is then discussed as an important determinant for the selection of the best analytical strategy in patients suspected to suffer from Schistosoma infection. Finally, it discusses the potential role of advanced technologies in the setting near to disease eradication is examined.
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Affiliation(s)
| | | | | | - Peter Odermatt
- Swiss Tropical and Public Health Institute, Basel, Switzerland
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8
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Esteban JG, Muñoz-Antoli C, Toledo R, Ash LR. Diagnosis of Human Trematode Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1154:437-471. [PMID: 31297770 DOI: 10.1007/978-3-030-18616-6_14] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Digenetic trematodes form a major group of human parasites, affecting a large number of humans, especially in endemic foci. Over 100 species have been reported infecting humans, including blood, lung, liver, and intestinal parasites. Traditionally, trematode infections have been diagnosed by parasitological methods based on the detection and the identification of eggs in different clinical samples. However, this is complicated due to the morphological similarity between eggs of different trematode species and other factors such as lack of sensitivity or ectopic locations of the parasites. Moreover, the problem is currently aggravated by migratory flows, international travel, international trade of foods, and changes in alimentary habits. Although efforts have been made for the development of immunological and molecular techniques, the detection of eggs through parasitological techniques remains as the gold standard for the diagnosis of trematodiases. In this chapter, we review the current status of knowledge on diagnostic techniques used when examining feces, urine, and sputum and also analyze the most relevant characteristics used to identify eggs with a quick key for the identification of eggs.
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Affiliation(s)
- J Guillermo Esteban
- Área de Parasitología, Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain.
| | - Carla Muñoz-Antoli
- Área de Parasitología, Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain
| | - Rafael Toledo
- Área de Parasitología, Departamento de Farmacia y Tecnología Farmacéutica y Parasitología, Facultad de Farmacia, Universidad de Valencia, Valencia, Spain
| | - Lawrence R Ash
- Infectious and Tropical Diseases, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, USA
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Asian Schistosomiasis: Current Status and Prospects for Control Leading to Elimination. Trop Med Infect Dis 2019; 4:tropicalmed4010040. [PMID: 30813615 PMCID: PMC6473711 DOI: 10.3390/tropicalmed4010040] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/12/2019] [Accepted: 02/12/2019] [Indexed: 12/22/2022] Open
Abstract
Schistosomiasis is an infectious disease caused by helminth parasites of the genus Schistosoma. Worldwide, an estimated 250 million people are infected with these parasites with the majority of cases occurring in sub-Saharan Africa. Within Asia, three species of Schistosoma cause disease. Schistosoma japonicum is the most prevalent, followed by S. mekongi and S. malayensis. All three species are zoonotic, which causes concern for their control, as successful elimination not only requires management of the human definitive host, but also the animal reservoir hosts. With regard to Asian schistosomiasis, most of the published research has focused on S. japonicum with comparatively little attention paid to S. mekongi and even less focus on S. malayensis. In this review, we examine the three Asian schistosomes and their current status in their endemic countries: Cambodia, Lao People's Democratic Republic, Myanmar, and Thailand (S. mekongi); Malaysia (S. malayensis); and Indonesia, People's Republic of China, and the Philippines (S. japonicum). Prospects for control that could potentially lead to elimination are highlighted as these can inform researchers and disease control managers in other schistosomiasis-endemic areas, particularly in Africa and the Americas.
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Juhász A, Majoros G. Investigations on the distribution of Schistosoma turkestanicum Skrjabin, 1913 (Trematoda: Schistosomatidae) infection of red deer in Hungary and a combined method for the detection of S. turkestanicum eggs in droppings. Acta Vet Hung 2018; 66:587-606. [PMID: 30580539 DOI: 10.1556/004.2018.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Additional geographical distribution of the Central European populations of Schistosoma turkestanicum and the detectability of their eggs in droppings were investigated in red deer samples, because this rare species had previously been shown only in a single Hungarian habitat. Samples from visceral organs, intestinal contents, and droppings on the ground from 11 hunting areas of Hungary were investigated to find a new presence of this fluke. Close to the first site of detection in the Gemenc forest another habitat along the southern border of the country was found where the parasite lives in red deer. Therefore, it is possible that the worm also occurs in neighbouring Serbia or Croatia. Schistosoma turkestanicum causes a low-intensity infection in red deer and this host sheds low amounts of eggs, therefore the eggs are difficult to detect. Droppings were cleared by sedimentation, filtered by sieve screening and then the eggs were flotated using solutions with an increasing density of 1200 g/L, 1300 g/L, 1350 g/L, and 1400 g/L while they were being stained red with acid fuchsin. Eggs in fresh faeces can be most efficiently separated from plant fibres using a flotation solution of 1350 g/L density, but in some cases eggs in old dung can be detected using a solution of a specific gravity lower or higher than that. By combining the advantages of the three concentration processes, eggs of S. turkestanicum, which are more recognisable by the red stain, can be found in samples in which they are present at a density lower than 1/g.
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Affiliation(s)
- Alexandra Juhász
- Department of Parasitology and Zoology, University of Veterinary Medicine, István u. 2, H-1078 Budapest, Hungary
| | - Gábor Majoros
- Department of Parasitology and Zoology, University of Veterinary Medicine, István u. 2, H-1078 Budapest, Hungary
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Garcia LS, Arrowood M, Kokoskin E, Paltridge GP, Pillai DR, Procop GW, Ryan N, Shimizu RY, Visvesvara G. Practical Guidance for Clinical Microbiology Laboratories: Laboratory Diagnosis of Parasites from the Gastrointestinal Tract. Clin Microbiol Rev 2018; 31:e00025-17. [PMID: 29142079 PMCID: PMC5740970 DOI: 10.1128/cmr.00025-17] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
This Practical Guidance for Clinical Microbiology document on the laboratory diagnosis of parasites from the gastrointestinal tract provides practical information for the recovery and identification of relevant human parasites. The document is based on a comprehensive literature review and expert consensus on relevant diagnostic methods. However, it does not include didactic information on human parasite life cycles, organism morphology, clinical disease, pathogenesis, treatment, or epidemiology and prevention. As greater emphasis is placed on neglected tropical diseases, it becomes highly probable that patients with gastrointestinal parasitic infections will become more widely recognized in areas where parasites are endemic and not endemic. Generally, these methods are nonautomated and require extensive bench experience for accurate performance and interpretation.
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Affiliation(s)
| | - Michael Arrowood
- Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of Foodborne, Waterborne, and Environmental Diseases, Waterborne Disease Prevention Branch, Atlanta, Georgia, USA
| | - Evelyne Kokoskin
- Public Health Ontario, Ottawa, Ontario, Canada
- Public Health Laboratories-Ottawa, Ottawa, Ontario, Canada
| | | | - Dylan R Pillai
- Calgary Laboratory Services, Diagnostic and Scientific Centre, Calgary, Alberta, Canada
| | - Gary W Procop
- Enterprise Test Utilization and Pathology Consultative Services, Cleveland, Ohio, USA
- Molecular Microbiology, Parasitology, and Mycology Laboratories, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio, USA
| | - Norbert Ryan
- Bacteriology and Parasitology, Victorian Infectious Diseases Reference Laboratory, Peter Doherty Institute, Melbourne, Victoria, Australia
| | | | - Govinda Visvesvara
- Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, Division of Foodborne, Waterborne, and Environmental Diseases, Waterborne Disease Prevention Branch, Atlanta, Georgia, USA
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12
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Abstract
Schistosomiasis in China has been substantially reduced due to an effective control programme employing various measures including bovine and human chemotherapy, and the removal of bovines from endemic areas. To fulfil elimination targets, it will be necessary to identify other possible reservoir hosts for Schistosoma japonicum and include them in future control efforts. This study determined the infection prevalence of S. japonicum in rodents (0-9·21%), dogs (0-18·37%) and goats (6·9-46·4%) from the Dongting Lake area of Hunan province, using a combination of traditional coproparasitological techniques (miracidial hatching technique and Kato-Katz thick smear technique) and molecular methods [quantitative real-time PCR (qPCR) and droplet digital PCR (ddPCR)]. We found a much higher prevalence in goats than previously recorded in this setting. Cattle and water buffalo were also examined using the same procedures and all were found to be infected, emphasising the occurrence of active transmission. qPCR and ddPCR were much more sensitive than the coproparasitological procedures with both KK and MHT considerably underestimating the true prevalence in all animals surveyed. The high level of S. japonicum prevalence in goats indicates that they are likely important reservoirs in schistosomiasis transmission, necessitating their inclusion as targets of control, if the goal of elimination is to be achieved in China.
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Abstract
Schistosomiasis is a major neglected tropical disease that afflicts more than 240 million people, including many children and young adults, in the tropics and subtropics. The disease is characterized by chronic infections with significant residual morbidity and is of considerable public health importance, with substantial socioeconomic impacts on impoverished communities. Morbidity reduction and eventual elimination through integrated intervention measures are the focuses of current schistosomiasis control programs. Precise diagnosis of schistosome infections, in both mammalian and snail intermediate hosts, will play a pivotal role in achieving these goals. Nevertheless, despite extensive efforts over several decades, the search for sensitive and specific diagnostics for schistosomiasis is ongoing. Here we review the area, paying attention to earlier approaches but emphasizing recent developments in the search for new diagnostics for schistosomiasis with practical applications in the research laboratory, the clinic, and the field. Careful and rigorous validation of these assays and their cost-effectiveness will be needed, however, prior to their adoption in support of policy decisions for national public health programs aimed at the control and elimination of schistosomiasis.
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Abd Al latif SS, Khamis OA. Schistosoma mansoni ova in seminal fluid. HUMAN ANDROLOGY 2014; 4:71-74. [DOI: 10.1097/01.xha.0000452306.06161.a7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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Wang S, Hu W. Development of "-omics" research in Schistosoma spp. and -omics-based new diagnostic tools for schistosomiasis. Front Microbiol 2014; 5:313. [PMID: 25018752 PMCID: PMC4072072 DOI: 10.3389/fmicb.2014.00313] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Indexed: 12/02/2022] Open
Abstract
Schistosomiasis, caused by dioecious flatworms in the genus Schistosoma, is torturing people from many developing countries nowadays and frequently leads to severe morbidity and mortality of the patients. Praziquantel based chemotherapy and morbidity control for this disease adopted currently necessitate viable and efficient diagnostic technologies. Fortunately, those “-omics” researches, which rely on high-throughput experimental technologies to produce massive amounts of informative data, have substantially contributed to the exploitation and innovation of diagnostic tools of schistosomiasis. In its first section, this review provides a concise conclusion on the progresses pertaining to schistosomal “-omics” researches to date, followed by a comprehensive section on the diagnostic methods of schistosomiasis, especially those innovative ones based on the detection of antibodies, antigens, nucleic acids, and metabolites with a focus on those achievements inspired by “-omics” researches. Finally, suggestions about the design of future diagnostic tools of schistosomiasis are proposed, in order to better harness those data produced by “-omics” studies.
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Affiliation(s)
- Shuqi Wang
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University Shanghai, China
| | - Wei Hu
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University Shanghai, China ; Key Laboratory of Parasite and Vector Biology of Ministry of Health, National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention Shanghai, China
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16
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Grenfell RFQ, Martins W, Enk M, Almeida A, Siqueira L, Silva-Moraes V, Oliveira E, Carneiro NFDF, Coelho PMZ. Schistosoma mansoni in a low-prevalence area in Brazil: the importance of additional methods for the diagnosis of hard-to-detect individual carriers by low-cost immunological assays. Mem Inst Oswaldo Cruz 2014; 108:S0074-02762013000300328. [PMID: 23778663 DOI: 10.1590/s0074-02762013000300011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 01/07/2013] [Indexed: 11/22/2022] Open
Abstract
Schistosomiasis diagnosis is based on the detection of eggs in the faeces, which is laborious and lacks sensitivity, especially for patients with a low parasite burden. Immunological assays for specific antibody detection are available, but they usually demonstrate low sensitivity and/or specificity. In this study, two simple immunological assays were evaluated for the detection of soluble Schistosoma mansoni adult worm preparation (SWAP) and egg-specific IgGs. These studies have not yet been evaluated for patients with low parasite burdens. Residents of an endemic area in Brazil donated sera and faecal samples for our study. The patients were initially diagnosed by a rigorous Kato-Katz analysis of 18 thick smears from four different stool samples. The ELISA-SWAP was successful for human diagnosis with 90% sensitivity and specificity, confirming the Kato-Katz diagnosis with nearly perfect agreement, as seen by the Kappa index (0.85). Although the ELISA-soluble S. mansoni egg antigen was 85% sensitive, it exhibited low specificity (80%; Kappa index: 0.75) and was more susceptible to cross-reactivity. We believe that immunological assays should be used in conjunction with Kato-Katz analysis as a supplementary tool for the diagnosis of schistosomiasis for patients with low infection burdens, which are usually hard to detect.
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Gomes LI, Enk MJ, Rabello A. Diagnosing schistosomiasis: where are we? Rev Soc Bras Med Trop 2014; 47:3-11. [DOI: 10.1590/0037-8682-0231-2013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 12/02/2013] [Indexed: 12/27/2022] Open
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18
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Diagnosis of Human Trematode Infections. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 766:293-327. [DOI: 10.1007/978-1-4939-0915-5_9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Knopp S, Becker SL, Ingram KJ, Keiser J, Utzinger J. Diagnosis and treatment of schistosomiasis in children in the era of intensified control. Expert Rev Anti Infect Ther 2013; 11:1237-58. [PMID: 24127662 DOI: 10.1586/14787210.2013.844066] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the current era of intensified and integrated control against schistosomiasis and other neglected tropical diseases, there is a need to carefully rethink and take into consideration disease-specific issues pertaining to the diagnosis, prevention, control and local elimination. Here, we present a comprehensive overview about schistosomiasis including recent trends in the number of people treated with praziquantel and the latest developments in diagnosis and control. Particular emphasis is placed on children. Identified research needs are offered for consideration; namely, expanding our knowledge about schistosomiasis in preschool-aged children, assessing and quantifying the impact of schistosomiasis on infectious and noncommunicable diseases, developing new antischistosomal drugs and child-friendly formulations, designing and implementing setting-specific control packages and developing highly sensitive, but simple diagnostic tools that are able to detect very light infections in young children and in people living in areas targeted for schistosomiasis elimination.
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Affiliation(s)
- Stefanie Knopp
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland
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Borges DS, de Souza JS, Romanzini J, Graeff-Teixeira C. Seeding experiments demonstrate poor performance of the hatching test for detecting small numbers of Schistosoma mansoni eggs in feces. Parasitol Int 2013; 62:543-7. [PMID: 23962504 DOI: 10.1016/j.parint.2013.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 08/01/2013] [Accepted: 08/12/2013] [Indexed: 11/19/2022]
Abstract
Parasitological methods for the evaluation of schistosomiasis tend to be limited when parasitic burdens are low, which is a major characteristic of low intensity transmission areas. While the hatching test (HT) method has been considered to be "very sensitive", reports of its capacity to detect low numbers of eggs remain scarce in the published literature. Our main hypothesis is that HT has limitations and cannot be recommended for diagnosing light infections or as a control of cure. Hence, this study aims to describe the performance of HT in detail, with respect to seeding experiments for egg numbers in the range of 4 to 24 eggs per gram (epg) of feces. Different numbers of eggs of Schistosoma mansoni were seeded in normal human feces. The first set of experiments evaluated the amount of feces (higher than 0.5 g prevented hatching), the proximity of the light source (50 cm was preferred), and the observation time required for the detection of miracidia (more than 3h did not add to sensitivity). HT was subsequently performed with 12, 10, 8, 6, 4, and 2 eggs in 0.5 g of feces. The final set of experiments was performed to analyze the initial filtration step, in which surgical gauze versus a 500 μm nylon mesh was compared and demonstrated losses of eggs that occurred with washing and gauze (better with nylon) sieving steps. The proposed method was found to produce 100% positivity for up to 12 epg, with a sharp decrease to 33% for 8 epg and less. In conclusion, HT is not recommended for diagnosing intestinal schistosomiasis in populations with light infections, considering the complexity of the procedure and its lack of effectiveness with fecal amounts higher than 0.5 g even at optimized conditions.
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Affiliation(s)
- Dieli Souza Borges
- Grupo de Parasitologia Biomédica da Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga 6681, Prédio 12C, 90619-900 Porto Alegre, Brazil
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21
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Oliveira GGD, Silva AMD, Jesus AMRD, Nunes MAP, Conceicao JO, Costa FO, Araujo JFD, Melo EVD. Epidemiological aspects of schistosomiasis in workers of the Movement of Landless Rural Workers. Rev Soc Bras Med Trop 2013; 46:519-21. [DOI: 10.1590/0037-8682-1412-2013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 02/21/2013] [Indexed: 11/22/2022] Open
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22
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Zhao GH, Li J, Blair D, Li XY, Elsheikha HM, Lin RQ, Zou FC, Zhu XQ. Biotechnological advances in the diagnosis, species differentiation and phylogenetic analysis of Schistosoma spp. Biotechnol Adv 2012; 30:1381-9. [DOI: 10.1016/j.biotechadv.2012.02.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 01/08/2012] [Accepted: 02/08/2012] [Indexed: 11/26/2022]
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Alejandria MM, Roman AD, Gonzales MLM, Amarillo ML, Belizario VY, Liu Q. Therapeutic and prophylactic drug interventions for Schistosomiasis japonicum. Hippokratia 2012. [DOI: 10.1002/14651858.cd010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Marissa M Alejandria
- Department of Medicine, Philippine General Hospital, University of the Philippines; Department of Clinical Epidemiology and Section of Infectious Diseases; Manila Philippines 1000
| | - Arthur Dessi Roman
- University of the Philippines, Philippines Gneral Hospital; Section of Infectious Diseases, Department of Medicine; Taft Avenue Ermita Manilla Philippines 1000
| | - Maria Liza M Gonzales
- College of Medicine-Philippine General Hospital, University of the Philippines; Department of Pediatrics; Taft Avenue Manila National Capital Region Philippines 1000
| | - Maria Lourdes Amarillo
- University of the Philippines, College of Medicine; Department of Clinical Epidemiology; 547 Pedro Gil St Ermita Manila Philippines 1000
| | - Vicente Y Belizario
- University of the Philippines; College of Public Health; 547 Pedro Gil St Ermita Manila Philippines 1000
| | - Qin Liu
- School of Public Health & Management, Chongqing Medical University; China Effective Health Care Network; No.1 YixueYuan Road Chongqing China 400016
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Enk MJ, Oliveira e Silva G, Rodrigues NB. Diagnostic accuracy and applicability of a PCR system for the detection of Schistosoma mansoni DNA in human urine samples from an endemic area. PLoS One 2012; 7:e38947. [PMID: 22701733 PMCID: PMC3372502 DOI: 10.1371/journal.pone.0038947] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 05/14/2012] [Indexed: 11/18/2022] Open
Abstract
Schistosomiasis caused by Schistosoma mansoni, one of the most neglected human parasitoses in Latin America and Africa, is routinely confirmed by microscopic visualization of eggs in stool. The main limitation of this diagnostic approach is its lack of sensitivity in detecting individual low worm burdens and consequently data on infection rates in low transmission settings are little reliable. According to the scientific literature, PCR assays are characterized by high sensitivity and specificity in detecting parasite DNA in biological samples. A simple and cost effective extraction method for DNA of Schistosoma mansoni from urine samples in combination with a conventional PCR assay was developed and applied in an endemic area. This urine based PCR system was tested for diagnostic accuracy among a population of a small village in an endemic area, comparing it to a reference test composed of three different parasitological techniques. The diagnostic parameters revealed a sensitivity of 100%, a specificity of 91.20%, positive and negative predictive values of 86.25% and 100%, respectively, and a test accuracy of 94.33%. Further statistical analysis showed a k index of 0.8806, indicating an excellent agreement between the reference test and the PCR system. Data obtained from the mouse model indicate the infection can be detected one week after cercariae penetration, opening a new perspective for early detection and patient management during this stage of the disease. The data indicate that this innovative PCR system provides a simple to handle and robust diagnostic tool for the detection of S. mansoni DNA from urine samples and a promising approach to overcome the diagnostic obstacles in low transmission settings. Furthermore the principals of this molecular technique, based on the examination of human urine samples may be useful for the diagnosis of other neglected tropical diseases that can be detected by trans-renal DNA.
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Affiliation(s)
- Martin Johannes Enk
- Laboratório de Esquistossomose, Centro de Pesquisas René Rachou, FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil.
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Cai YC, Guo J, Chen SH, Tian LG, Steinmann P, Chen MX, Li H, Ai L, Chen JX. Chicken egg yolk antibodies (IgY) for detecting circulating antigens of Schistosoma japonicum. Parasitol Int 2012; 61:385-90. [PMID: 22342296 DOI: 10.1016/j.parint.2012.01.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 01/05/2012] [Accepted: 01/20/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND IgY isolated from egg yolk has been widely used in immunodiagnostic tests, including tests to detect circulating antigen (soluble egg antigen or SEA) of Schistosoma japonicum. RESULTS A sandwich ELISA was established using a combination of anti-S. japonicum SEA-IgY polyclonal antibodies and IgM monoclonal antibodies. To explore sensitivity and specificity of the sandwich ELISA, serum samples from 43 patients infected with S. japonicum were tested. All acute cases and 91.3% of the chronic cases showed a positive reaction. Only 5% of the control sera from healthy persons gave a positive response. Cross-reactions with antibodies to nine other parasites were rare. CONCLUSION The developed immunoassay is reasonably sensitive and specific. It could be used for field research and treatment efficacy assessments.
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Affiliation(s)
- Yu-Chun Cai
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai 200025, PR China.
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TEIXEIRA de MELO T, MICHEL de ARAUJO J, Do VALLE DURÃES F, CALIARI MV, OLIVEIRA SC, COELHO PMZ, FONSECA CT. Immunization with newly transformed Schistosoma mansoni schistosomula tegument elicits tegument damage, reduction in egg and parasite burden. Parasite Immunol 2010; 32:749-59. [DOI: 10.1111/j.1365-3024.2010.01244.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Coelho PMZ, Jurberg AD, Oliveira AA, Katz N. Use of a saline gradient for the diagnosis of schistosomiasis. Mem Inst Oswaldo Cruz 2010; 104:720-3. [PMID: 19820832 DOI: 10.1590/s0074-02762009000500010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 06/04/2009] [Indexed: 11/22/2022] Open
Abstract
The development of novel methods for parasitological diagnosis that are both highly sensitive and low in cost has been strongly recommended by the World Health Organization. In this study, a new technique for diagnosis of schistosomiasis mansoni is proposed based on the differential sedimentation of eggs when subjected to a slow continuous flux of 3% saline solution through a porous plaque. This influx suspends low-density faecal material, effectively cleaning the sample. The remaining sediment covering the porous plaque surface is then transferred to a glass slide and examined under a bright field microscope. Twelve Kato-Katz slides were used for comparison in the present study. Our results suggest that the saline gradient method detects a significantly higher number of eggs than the 12 Kato-Katz slides (p < 0.0001). We also found microscopic inspection to be quicker and easier with our newly described method. After cleaning the sample, the obtained sediment can also be conserved in a 10% formaldehyde solution and examined for at least 45 days later without statistically significant egg count differences.
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Affiliation(s)
- Paulo Marcos Z Coelho
- Laboratório de Esquistossomose, Centro de Pesquisas René Rachou-Fiocruz, Av. Augusto de Lima 1715, Belo Horizonte, MG, Brazil.
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Jurberg AD, Gonçalves T, Costa TA, de Mattos ACA, Pascarelli BM, de Manso PPA, Ribeiro-Alves M, Pelajo-Machado M, Peralta JM, Coelho PMZ, Lenzi HL. The embryonic development of Schistosoma mansoni eggs: proposal for a new staging system. Dev Genes Evol 2009; 219:219-34. [PMID: 19415326 DOI: 10.1007/s00427-009-0285-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Accepted: 04/03/2009] [Indexed: 11/25/2022]
Abstract
Schistosomiasis is a water-borne parasitic illness caused by neoophoran trematodes of the genus Schistosoma. Using classical histological techniques and whole-mount preparations, the present work describes the embryonic development of Schistosoma mansoni eggs in the murine host and compares it with eggs maintained under in vitro conditions. Two pre-embryonic stages occur inside the female worm: the prezygotic stage is characterized by the release of mature oocytes from the female ovary until its fertilization. The zygotic stage encompasses the migration of the zygote through the ootype, where the eggshell is formed, to the uterus. Fully formed eggs are laid still undeveloped, without having suffered any cleavage. In the outside environment, eight embryonic stages can be defined: stage 1 refers to early cleavages and the beginning of yolk fusion. Stage 2 represents late cleavage, with the formation of a stereoblastula and the onset of outer envelope differentiation. Stage 3 is defined by the elongation of the embryonic primordium and the onset of inner envelope formation. At stage 4, the first organ primordia arise. During stages 5 to 7, tissue and organ differentiation occurs (neural mass, epidermis, terebratorium, musculature, and miracidial glands). Stage 7 is characterized by the nuclear condensation of neurons of the central neural mass. Stage 8 refers to the fully formed larva, presenting muscular contraction, cilia, and flame-cell beating. This staging system was compared to a previous classification and could underlie further studies on egg histoproteomics (morphological localizome). The differentiation of embryonic structures and their probable roles in granulomatogenesis are discussed herein.
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Affiliation(s)
- Arnon D Jurberg
- Laboratório de Patologia, Instituto Oswaldo Cruz/Fundação Oswaldo Cruz, Pavilhão Gomes de Faria. Av. Brasil, 4365-Manguinhos, Rio de Janeiro 21040-900, RJ, Brazil.
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