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Ta-Tang TH, Febrer-Sendra B, Berzosa P, Rubio JM, Romay-Barja M, Ncogo P, Agudo D, Herrador Z, Fernández-Soto P, Muro A, Benito A. Comparison of three PCR-based methods to detect Loa loa and Mansonella perstans in long-term frozen storage dried blood spots. Trop Med Int Health 2022; 27:686-695. [PMID: 35653502 DOI: 10.1111/tmi.13786] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Loa loa and Mansonella perstans are two very common filarial species in Africa. Although microscopy is the traditional diagnostic method for human filariasis, several polymerase chain reaction (PCR) methods have emerged as an alternative approach for identifying filarial parasites. The aim of this study is to compare three molecular methods and decide which is the most suitable for diagnosing human loiasis and mansonellosis in non-endemic regions using dried blood spot (DBS) as a medium for sample collection and storage. METHODS A total of 100 DBS samples, with their corresponding thin and thick blood smears, were selected for this study. Microscopy was used as the reference method to diagnose and calculate the microfilaraemia. Filarial DNA was extracted using the saponin/Chelex method and the DNA isolated was assayed by Filaria-real time-PCR, filaria-nested PCR, and cytochrome oxidase I PCR. All PCR products were subsequently purified and sequenced. The statistical values for each molecular test were calculated and compared. RESULTS Overall, 64 samples were identified as negative by all tests and a further 36 samples were positive by at least one of the methods used. The sensitivity and specificity were similar for the different molecular methods, all of which demonstrated good agreement with microscopy. CONCLUSIONS Based on this study, and from a practical point of view (single and short amplification round), the optimal technique for diagnosing filarial infection in non-endemic regions is filaria-real time-PCR, which presents high sensitivity and specificity and is also able to detect a wide range of human filariae.
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Affiliation(s)
- Thuy-Huong Ta-Tang
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
| | - Begoña Febrer-Sendra
- Cooperative Research Network in Tropical Diseases, Madrid, Spain.,Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Pedro Berzosa
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
| | - José Miguel Rubio
- Cooperative Research Network in Tropical Diseases, Madrid, Spain.,Malaria and Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - María Romay-Barja
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
| | - Policarpo Ncogo
- Ministry of Health, Malabo, Equatorial Guinea.,Fundación Estatal, Salud, Infancia y Bienestar Social, Madrid, Spain
| | - Diego Agudo
- Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, Madrid, Spain
| | - Zaida Herrador
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
| | - Pedro Fernández-Soto
- Cooperative Research Network in Tropical Diseases, Madrid, Spain.,Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Antonio Muro
- Cooperative Research Network in Tropical Diseases, Madrid, Spain.,Infectious and Tropical Diseases Research Group (e-INTRO), Biomedical Research Institute of Salamanca-Research Centre for Tropical Diseases at the University of Salamanca, Faculty of Pharmacy, University of Salamanca, Salamanca, Spain
| | - Agustín Benito
- Malaria and Neglected Tropical Diseases Laboratory, National Centre of Tropical Medicine, Institute of Health Carlos III, Biomedical Research Networking Center of Infectious Diseases, Madrid, Spain.,Cooperative Research Network in Tropical Diseases, Madrid, Spain
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2
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Brattig NW, Cheke RA, Garms R. Onchocerciasis (river blindness) - more than a century of research and control. Acta Trop 2021; 218:105677. [PMID: 32857984 DOI: 10.1016/j.actatropica.2020.105677] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/06/2020] [Accepted: 08/21/2020] [Indexed: 12/14/2022]
Abstract
This review summarises more than a century of research on onchocerciasis, also known as river blindness, and its control. River blindness is an infection caused by the tissue filaria Onchocerca volvulus affecting the skin, subcutaneous tissue and eyes and leading to blindness in a minority of infected persons. The parasite is transmitted by its intermediate hosts Simulium spp. which breed in rivers. Featured are history and milestones in onchocerciasis research and control, state-of-the-art data on the parasite, its endobacteria Wolbachia, on the vectors, previous and current prevalence of the infection, its diagnostics, the interaction between the parasite and its host, immune responses and the pathology of onchocerciasis. Detailed information is documented on the time course of control programmes in the afflicted countries in Africa and the Americas, a long road from previous programmes to current successes in control of the transmission of this infectious disease. By development, adjustment and optimization of the control measures, transmission by the vector has been interrupted in foci of countries in the Americas, in Uganda, in Sudan and elsewhere, followed by onchocerciasis eliminations. The current state and future perspectives for control, elimination and eradication within the next 20-30 years are described and discussed. This review contributes to a deeper comprehension of this disease by a tissue-dwelling filaria and it will be helpful in efforts to control and eliminate other filarial infections.
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3
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Ngwasiri NN, Brattig NW, Ndjonka D, Liebau E, Paguem A, Leusder D, Kingsley MT, Eisenbarth A, Renz A, Daniel AM. Galectins from Onchocerca ochengi and O. volvulus and their immune recognition by Wistar rats, Gudali zebu cattle and human hosts. BMC Microbiol 2021; 21:5. [PMID: 33407120 PMCID: PMC7788699 DOI: 10.1186/s12866-020-02064-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022] Open
Abstract
Background During the last two decades research on animal filarial parasites, especially Onchocerca ochengi, infecting cattle in savanna areas of Africa revealed that O. ochengi as an animal model has biological features that are similar to those of O. volvulus, the aetiological agent of human onchocerciasis. There is, however, a paucity of biochemical, immunological and pathological data for O. ochengi. Galectins can be generated by parasites and their hosts. They are multifunctional molecules affecting the interaction between filarial parasites and their mammalian hosts including immune responses. This study characterized O. ochengi galectin, verified its immunologenicity and established its immune reactivity and that of Onchocerca volvulus galectin. Results The phylogenetic analysis showed the high degree of identity between the identified O. ochengi and the O. volvulus galectin-1 (ß-galactoside-binding protein-1) consisting only in one exchange of alanine for serine. O. ochengi galectin induced IgG antibodies during 28 days after immunization of Wistar rats. IgG from O. ochengi-infected cattle and O. volvulus-infected humans cross-reacted with the corresponding galectins. Under the applied experimental conditions in a cell proliferation test, O. ochengi galectin failed to significantly stimulate peripheral blood mononuclear cells (PBMCs) from O. ochengi-infected cattle, regardless of their parasite load. Conclusion An O. ochengi galectin gene was identified and the recombinantly expressed protein was immunogenic. IgG from Onchocerca-infected humans and cattle showed similar cross-reaction with both respective galectins. The present findings reflect the phylogenetic relationship between the two parasites and endorse the appropriateness of the cattle O. ochengi model for O. volvulus infection research. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-020-02064-3.
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Affiliation(s)
| | - Norbert W Brattig
- Department Molecular Medicine, Bernhard Nocht Institute of Tropical Medicine, Hamburg, Germany
| | | | - Eva Liebau
- University of Muenster, Münster, Germany
| | - Archile Paguem
- University of Ngaoundéré, Ngaoundéré, Cameroon.,Department Comparative Zoology, Eberhard Karls University, Institute of Evolution and Ecology, Tübingen, Germany.,Department of Veterinary Medicine, University of Buea, Buea, Cameroon
| | | | - Manchang Tanyi Kingsley
- Department of Veterinary Medicine, University of Buea, Buea, Cameroon.,Veterinary Research Laboratory, IRAD Wakwa Regional Centre, Ngaoundéré, Cameroon
| | - Albert Eisenbarth
- Department Comparative Zoology, Eberhard Karls University, Institute of Evolution and Ecology, Tübingen, Germany.,Programme Onchocercoses, Station of the University of Tübingen, Ngaoundéré, Cameroon
| | - Alfons Renz
- Department Comparative Zoology, Eberhard Karls University, Institute of Evolution and Ecology, Tübingen, Germany.,Programme Onchocercoses, Station of the University of Tübingen, Ngaoundéré, Cameroon
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4
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Unnasch TR, Golden A, Cama V, Cantey PT. Diagnostics for onchocerciasis in the era of elimination. Int Health 2018; 10:i20-i26. [PMID: 29471336 PMCID: PMC5881263 DOI: 10.1093/inthealth/ihx047] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 10/19/2017] [Accepted: 11/06/2017] [Indexed: 12/31/2022] Open
Abstract
In the past few years, efforts to eliminate onchocerciasis from Africa have intensified. These efforts are primarily based on the mass distribution of the anti-helminthic drug Mectizan™ (ivermectin). This program has led to the development of new guidelines by the World Health Organization for the verification that transmission has been suppressed and eventually eliminated. The requirements of diagnostic tools for this purpose differ in many ways from tests used to diagnose infection in individuals. In this review, we summarize the progress that has been made to identify diagnostics that meet the specialized requirements needed to verify onchocerciasis elimination, discuss why these tests were selected and summarize the needs that still exist to complete the arsenal of diagnostic tools that will be useful as the goal of elimination is achieved.
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Affiliation(s)
- Thomas R Unnasch
- Center for Global Health Infectious Disease Research, College of Public Health, University of South Florida, 3720 Spectrum Blvd., Suite 304, Tampa, FL 33612, USA
| | | | - Vitaliano Cama
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GAUSA
| | - Paul T Cantey
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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5
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Moya L, Herrador Z, Ta-Tang TH, Rubio JM, Perteguer MJ, Hernandez-González A, García B, Nguema R, Nguema J, Ncogo P, Garate T, Benito A, Sima A, Aparicio P. Evidence for Suppression of Onchocerciasis Transmission in Bioko Island, Equatorial Guinea. PLoS Negl Trop Dis 2016; 10:e0004829. [PMID: 27448085 PMCID: PMC4957785 DOI: 10.1371/journal.pntd.0004829] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 06/16/2016] [Indexed: 11/30/2022] Open
Abstract
Onchocerciasis or "river blindness" is a chronic parasitic neglected tropical disease which is endemic both in mainland and insular Equatorial Guinea. We aim to estimate the current epidemiological situation of onchocerciasis in Bioko Island after vector elimination in 2005 and more than sixteen years of Community Directed Treatment with Ivermectin (CDTI) by using molecular and serological approaches for onchocerciasis diagnosis. A community-based cross-sectional study was carried out in Bioko Island from mid-January to mid-February 2014. A total of 544 study participants were recruited. A complete dermatological examination was performed and three skin snips were performed in every participant for parasitological and molecular assessments. Blood spots were also taken for determination of Ov16 IgG4 antibodies trough an “in-house” ELISA assay. Overall, we found 15 out of 522 individuals suffering any onchocerciasis specific cutaneous lesions and 16 out of 528 (3.0%) with onchocercal nodules in the skin. Nodules were significantly associated with age, being more common in subjects older than 10 years than in younger people (3.9% vs. 0%, p = 0.029). Regarding the onchocerciasis laboratory assessment, no positive parasitological test for microfilaria detection was found in the skin snips. The calculated seroprevalence through IgG4 serology was 7.9%. No children less than 10 years old were found to be positive for this test. Only one case was positive for Onchocerca volvulus (O. volvulus) after skin PCR. The present study points out that the on-going mass ivermectin treatment has been effective in reducing the prevalence of onchocerciasis and corroborates the interruption of transmission in Bioko Island. To our knowledge, this is the first time that accurate information through molecular and serological techniques is generated to estimate the onchocerciasis prevalence in this zone. Sustained support from the national program and appropriate communication and health education strategies to reinforce participation in CDTI activities are essential to ensure progress towards onchocerciasis elimination in the country. Onchocerciasis or “river blindness” is a chronic parasitic disease which is mainly found in Sub-Saharan Africa. Onchocerciasis is endemic in both mainland and insular Equatorial Guinea. Huge achievements have been made on onchocerciasis control in Bioko Island in the last years, and the country is moving fast towards elimination. In the new elimination context, monitoring and evaluation activities with more sensitive diagnostic tools become especially necessary in order to confirm that transmission has been interrupted. Previous data on the epidemiological situation of onchocerciasis in Bioko Island are mainly based on microfilaria (MF) skin snip assessments. We aim to create evidence towards the fact that onchocerciasis transmission might have been achieved in Bioko Island after more than sixteen years of onchocerciasis control activities by using molecular and serological technics for onchocerciasis diagnosis.
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Affiliation(s)
- Laura Moya
- Jimenez Diaz Foundation, Madrid, Spain
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
- * E-mail:
| | - Zaida Herrador
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
| | - Thuy Huong Ta-Tang
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Jose Miguel Rubio
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Maria Jesús Perteguer
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Ana Hernandez-González
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Belén García
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
| | - Rufino Nguema
- National Program for Onchocerciasis and other Filariasis Control, Ministry of Health, Malabo, Equatorial Guinea
| | - Justino Nguema
- National Program for Onchocerciasis and other Filariasis Control, Ministry of Health, Malabo, Equatorial Guinea
| | - Policarpo Ncogo
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
| | - Teresa Garate
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
- Malaria & Other Emerging Parasitic Diseases Laboratory, National Microbiology Center, Institute of Health Carlos III, Madrid, Spain
| | - Agustín Benito
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
| | - Anacleto Sima
- National Program for Onchocerciasis and other Filariasis Control, Ministry of Health, Malabo, Equatorial Guinea
| | - Pilar Aparicio
- National Center for Tropical Medicine, Institute of Health Carlos III, Madrid, Spain
- Network Biomedical Research on Tropical Diseases (RICET in Spanish), Madrid, Spain
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6
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Ajonina-Ekoti I, Ndjonka D, Tanyi MK, Wilbertz M, Younis AE, Boursou D, Kurosinski MA, Eberle R, Lüersen K, Perbandt M, Breloer M, Brattig NW, Liebau E. Functional characterization and immune recognition of the extracellular superoxide dismutase from the human pathogenic parasite Onchocerca volvulus (OvEC-SOD). Acta Trop 2012; 124:15-26. [PMID: 22677600 DOI: 10.1016/j.actatropica.2012.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 05/23/2012] [Accepted: 05/28/2012] [Indexed: 01/04/2023]
Abstract
Onchocerca volvulus is a human pathogenic filarial nematode causing chronic onchocerciasis, a disease characterized by chronic skin and eye lesions. Despite attempts to control this infection from many perspectives, it still remains a threat to public health because of adverse effects of available drugs and recent reports of drug resistance. Under control of an intact immune system, O. volvulus survives for a long time in the host by employing a variety of strategies including the utility of antioxidant enzymes. In the present study, we focus on the extracellular superoxide dismutase from O. volvulus (OvEC-SOD) found in the excretory/secretory products of adult worms. Contrary to previous studies, the OvEC-SOD was found to have a 19 amino acid long signal peptide that is cleaved off during the process of maturation. To validate this result, we designed a novel method based on Caenorhabditis elegans cup5(ar465) mutants to specifically evaluate signal peptide-mediated secretion of nematodal proteins. Following purification, the recombinant OvEC-SOD was active as a dimer. Site-directed mutagenesis of the three cysteines present in the OvEC-SOD shows that enzyme activity is markedly reduced in the Cys-192 mutant. A homology model of the OvEC-SOD underlines the importance of Cys-192 for the stabilization of the adjacent active site channel. The generation of a humoral immune response to secretory OvEC-SOD was indicated by demonstrating IgG reactivity in sera from patients infected with O. volvulus while the cross-reactivity of IgG in plasma samples from cows, infected with the most closely related parasite Onchocerca ochengi, occurred only marginally. High IgG1 and IgM titres were recorded in sera from mice infected with the filaria Litomosoides sigmodontis, however, low or no cellular proliferative responses were observed. Thus, the present data suggest that secretory OvEC-SOD is a target of the humoral immune response in human onchocerciasis and induced strongest IgG responses in hyperreactive onchocerciasis. Furthermore, humoral response during murine infection induced SOD-specific IgG that cross-reacted with OvEC-SOD.
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7
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Simonsen PE, Onapa AW, Asio SM. Mansonella perstans filariasis in Africa. Acta Trop 2011; 120 Suppl 1:S109-20. [PMID: 20152790 DOI: 10.1016/j.actatropica.2010.01.014] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 01/27/2010] [Accepted: 01/29/2010] [Indexed: 11/19/2022]
Abstract
Mansonella perstans is a vector-borne human filarial nematode, transmitted by tiny blood-sucking flies (biting midges). It is widespread in many parts of Sub-Saharan Africa and also occurs in parts of Central and South America. Despite the commonness of this parasite very few studies have been carried out on its epidemiology and on the morbidity resulting from it, and only few thorough drug trials have been conducted to look for effective and suitable drugs and drug regimens for treatment and control. Here, we review currently available knowledge on M. perstans infections in Africa, including documented aspects of biology, vectors, transmission, diagnosis, epidemiology, morbidity and treatment. It is concluded that there is an urgent need for more research on this widespread but greatly neglected infection in order to properly assess its public health significance and as a background for identifying and recommending optimal means and strategies for treatment and control.
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Affiliation(s)
- Paul E Simonsen
- DBL-Centre for Health Research and Development, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 57, 1871 Frederiksberg C, Denmark.
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8
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Pardo J, Pérez-Arellano JL, Galindo I, Belhassen M, Cordero M, Muro A. [Diagnosing imported helminthiasis]. Enferm Infecc Microbiol Clin 2007; 25:329-35. [PMID: 17504687 DOI: 10.1157/13102269] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In recent years, there has been an increase in cases of imported helminthiasis in Spain because of two complementary causes: immigration and international travel. Although the prevalence of helminthiasis is high in the immigrant population, the risk of transmission to the Spanish population is low. In this review, we provide clues to aid in the diagnosis of the helminthiasis, highlighting the geographic characteristics, clinical findings and analytical results of the most frequent types. The low sensitivity of the classic parasitological diagnostic test, mainly in tissue helminthiasis, is described. In addition, the advantages and limitations of the common serological methods for detecting related circulating antigens and antibodies are presented. Certain molecular methods used in the diagnosis of imported helminthiasis and the best strategies for screening of this condition are discussed.
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Affiliation(s)
- Javier Pardo
- Laboratorio de Inmunología Parasitaria y Molecular, CISET, Facultad de Farmacia, Universidad de Salamanca, España.
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9
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Borchert N, Becker-Pauly C, Wagner A, Fischer P, Stöcker W, Brattig NW. Identification and characterization of onchoastacin, an astacin-like metalloproteinase from the filaria Onchocerca volvulus. Microbes Infect 2007; 9:498-506. [PMID: 17347015 DOI: 10.1016/j.micinf.2007.01.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 01/16/2007] [Indexed: 10/23/2022]
Abstract
The tissue-invasive nematode Onchocerca volvulus causes skin and eye pathology in human onchocerciasis. While the adult females reside sessile in subcutaneous nodules, the microfilariae are abundantly released from the nodules, males and juvenile worms migrate through the host tissue. Matrix-degrading metallo- and serine proteinases have been detected in excretory-secretory worm products that may be essential for migration of the mobile stages. In this study, a 1713bp long cDNA encoding for a putative proteinase of O. volvulus has been isolated. The predicted protein sequence includes a signal peptide indicating secretion to the extracellular space, a propeptide, an astacin-like protease domain, an EGF-like and a CUB-domain, thereby identifying the protein as a member of the astacin family of zinc endopeptidases. Onchoastacin, Ov-AST-1, is most closely related to a subfamily comprising nematode astacins including Caenorhabditis and Ancylostoma. Ov-AST-1 was expressed as a recombinant protein in baculovirus-infected insect cells and exhibited enzymatic activity. The exposure of onchoastacin to the host immune system is indicated by demonstration of IgG reacting with the recombinant Ov-AST-1 and with two peptides of the protein. Since a homologous metalloproteinase is part of a promising hookworm vaccine, Ov-AST-1 may be a candidate for intervention strategies in filarial infections.
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Affiliation(s)
- Nadine Borchert
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, D-20359 Hamburg, Germany
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10
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Rodríguez-Pérez MA, Domínguez-Vázquez A, Méndez-Galván J, Sifuentes-Rincón AM, Larralde-Corona P, Barrera-Saldaña HA, Bradley JE. Antibody detection tests for Onchocerca volvulus: comparison of the sensitivity of a cocktail of recombinant antigens used in the indirect enzyme-linked immunosorbent assay with a rapid-format antibody card test. Trans R Soc Trop Med Hyg 2004; 97:539-41. [PMID: 15307420 DOI: 10.1016/s0035-9203(03)80018-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
There is a need for a specific, sensitive, and practical diagnostic test to monitor onchocerciasis elimination campaigns. In April 2001, an enzyme-linked immunosorbent assay (ELISA) using 3 recombinant antigens and a rapid-format antibody card test (immunochromatographic test; ICT) using an individual antigen were compared in a Mexican population with onchocerciasis. The sensitivity of the ELISA and ICT was 97% and 86%, respectively.
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Affiliation(s)
- Mario A Rodríguez-Pérez
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Boulevard del Maestro esquina Elías Piña, Reynosa, Tamaulipas, Mexico.
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11
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Fischer P, Bonow I, Büttner DW, Kamal IH, Liebau E. An aspartate aminotransferase of Wolbachia endobacteria from Onchocerca volvulus is recognized by IgG1 antibodies from residents of endemic areas. Parasitol Res 2003; 90:38-47. [PMID: 12743802 DOI: 10.1007/s00436-002-0813-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2002] [Accepted: 11/22/2002] [Indexed: 11/26/2022]
Abstract
Wolbachia are intracellular alpha-proteobacteria, closely related to Rickettsia, that infect various arthropods and filarial parasites. In the present study, the cDNA encoding the aspartate aminotransferase (AspAT) of Wolbachia from the human pathogenic filarial parasite Onchocerca volvulus (Ov-WolAspAT) was identified. At the amino acid level, the identity of the Ov-WolAspAT was 56% to Rickettsia prowazekii AspAT and 54% to the AspAT of the nitrogen-fixing bacterium Sinorhizobium meliloti, but the highest degree of identity was found to the putative AspAT of Wolbachia from Brugia malayi and Drosophila melanogaster (85%). All of these bacterial AspATs are members of the AspAT subclass Ib. A 35 kDa fragment of the Ov-WolAspAT was expressed in Escherichia coli, and immunolocalization using polyclonal antibodies against this antigen revealed that Ov-WolAspAT is present in a considerable proportion of the Wolbachia from O. volvulus, as well as in the endobacteria of several other filarial parasites. Western blot analysis using recombinant Ov-WolAspAT as antigen showed that IgG1 antibodies were present in 70 (51%) individuals living in areas endemic for O. volvulus, B. malayi or Wuchereria bancrofti and no IgG4 or IgE antibodies were found. Among 40 sera of persons from Uganda and Liberia who were putatively not infected with human filarial parasites, 11 (28%) individuals presented IgG1 antibodies, while none of the 33 sera from healthy Europeans and none of the 14 sera from patients with proven Rickettsia or Brucella infections reacted with the antigen. These results also show that an intracellular protein of Wolbachia endobacteria (WolAspAT) acts as antigen in human filariasis.
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Affiliation(s)
- Peter Fischer
- Molecular Parasitology Section, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, 20359 Hamburg, Germany.
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12
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Hernández Machín B, Borrego Hernando L, Báez Acosta B, Martín Sánchez A, Hernández Hernández B, Pérez Arellano J. Inmigrante con hiperpigmentación unilateral en extremidades inferiores y eosinofilia. Rev Clin Esp 2003. [DOI: 10.1016/s0014-2565(03)71194-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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13
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Walther M, Muller R. Diagnosis of human filariases (except onchocerciasis). ADVANCES IN PARASITOLOGY 2003; 53:149-93. [PMID: 14587698 DOI: 10.1016/s0065-308x(03)53004-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The traditional method of diagnosing filarial infections is to examine blood or skin samples for microfilariae and for many this is still the standard procedure. However, since the present global campaign to eliminate lymphatic filariasis new diagnostic tools have emerged like PCR, antigen detection using finger-prick blood taken during the day and ultrasound to visualize adult worms. The last two can be applied in endemic countries with limited resources and enable the detection of early infections. As well as their value in control schemes, the latter is particularly important for the individual since recent research has shown that damage is usually caused long before symptoms appear. The usefulness in different situations and the advantages and disadvantages of the various new tools for diagnosis of lymphatic filariasis are discussed. For loiasis, immunodiagnostic methods have not been very successful but repetitive DNA sequences in the Loa genome have been found to be species specific. Techniques based on them are particularly useful for diagnosing cases of occult infection without microfilaraemia. There have been no advances in the diagnosis of Mansonella perstans but both immunodiagnostic and PCR tests show promise in differentiating M. streptocerca, and the latter in differentiating M.ozzardi, from Onchocerca. In addition to the human filariae, the dog parasites Dirofilaria immitis and D. repens can also occur in humans but do not produce microfilariae in them. ELISAs and PCR probes have been devised and can usefully differentiate between pulmonary dirofilariasis and lung cancer.
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Affiliation(s)
- Michael Walther
- Centre for Clinical Vaccinology and Tropical Medicine, Churchill Hospital, University of Oxford, Old Road, Headington, Oxford OX3 7LJ, UK
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Abstract
As research progress has led to programs for the elimination of onchocerciasis as a public health problem, research must now be intensified to protect elimination efforts. A profound understanding of the immunology in the human-parasite relationship is required for predicting the impacts of an altered immune response in a population post-microfilaricide treatment, and for the development of a vaccine against onchocerciasis, a highly desirable tool to guarantee sustained elimination success. This article summarizes the recent advancements in understanding the human immune mechanisms against onchocerciasis, and focuses on the new concept of T-cell suppressor responses as a major counterbalance mechanism for effector responses driven by T helper 1 and T helper 2 cells against the filarial worms.
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Affiliation(s)
- Achim Hoerauf
- Bernhard Nocht Institute of Tropical Medicine, Bernhard-Nocht-Strasse 74, 20359, Hamburg, Germany.
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