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N'Djetchi MK, Camara O, Koffi M, Camara M, Kaba D, Kaboré J, Tall A, Rotureau B, Glover L, Traoré MB, Koné M, Coulibaly B, Adingra GP, Soumah A, Gassama M, Camara AD, Compaoré CFA, Camara A, Boiro S, Anton EP, Bessell P, Van Reet N, Bucheton B, Jamonneau V, Bart JM, Solano P, Biéler S, Lejon V. Specificity of serological screening tests and reference laboratory tests to diagnose gambiense human African trypanosomiasis: a prospective clinical performance study. Infect Dis Poverty 2024; 13:53. [PMID: 38978124 PMCID: PMC11229219 DOI: 10.1186/s40249-024-01220-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 06/25/2024] [Indexed: 07/10/2024] Open
Abstract
BACKGROUND Serological screening tests play a crucial role to diagnose gambiense human African trypanosomiasis (gHAT). Presently, they preselect individuals for microscopic confirmation, but in future "screen and treat" strategies they will identify individuals for treatment. Variability in reported specificities, the development of new rapid diagnostic tests (RDT) and the hypothesis that malaria infection may decrease RDT specificity led us to evaluate the specificity of 5 gHAT screening tests. METHODS During active screening, venous blood samples from 1095 individuals from Côte d'Ivoire and Guinea were tested consecutively with commercial (CATT, HAT Sero-K-SeT, Abbott Bioline HAT 2.0) and prototype (DCN HAT RDT, HAT Sero-K-SeT 2.0) gHAT screening tests and with a malaria RDT. Individuals with ≥ 1 positive gHAT screening test underwent microscopy and further immunological (trypanolysis with T.b. gambiense LiTat 1.3, 1.5 and 1.6; indirect ELISA/T.b. gambiense; T.b. gambiense inhibition ELISA with T.b. gambiense LiTat 1.3 and 1.5 VSG) and molecular reference laboratory tests (PCR TBRN3, 18S and TgsGP; SHERLOCK 18S Tids, 7SL Zoon, and TgsGP; Trypanozoon S2-RT-qPCR 18S2, 177T, GPI-PLC and TgsGP in multiplex; RT-qPCR DT8, DT9 and TgsGP in multiplex). Microscopic trypanosome detection confirmed gHAT, while other individuals were considered gHAT free. Differences in fractions between groups were assessed by Chi square and differences in specificity between 2 tests on the same individuals by McNemar. RESULTS One gHAT case was diagnosed. Overall test specificities (n = 1094) were: CATT 98.9% (95% CI: 98.1-99.4%); HAT Sero-K-SeT 86.7% (95% CI: 84.5-88.5%); Bioline HAT 2.0 82.1% (95% CI: 79.7-84.2%); DCN HAT RDT 78.2% (95% CI: 75.7-80.6%); and HAT Sero-K-SeT 2.0 78.4% (95% CI: 75.9-80.8%). In malaria positives, gHAT screening tests appeared less specific, but the difference was significant only in Guinea for Abbott Bioline HAT 2.0 (P = 0.03) and HAT Sero-K-Set 2.0 (P = 0.0006). The specificities of immunological and molecular laboratory tests in gHAT seropositives were 98.7-100% (n = 399) and 93.0-100% (n = 302), respectively. Among 44 reference laboratory test positives, only the confirmed gHAT patient and one screening test seropositive combined immunological and molecular reference laboratory test positivity. CONCLUSIONS Although a minor effect of malaria cannot be excluded, gHAT RDT specificities are far below the 95% minimal specificity stipulated by the WHO target product profile for a simple diagnostic tool to identify individuals eligible for treatment. Unless specificity is improved, an RDT-based "screen and treat" strategy would result in massive overtreatment. In view of their inconsistent results, additional comparative evaluations of the diagnostic performance of reference laboratory tests are indicated for better identifying, among screening test positives, those at increased suspicion for gHAT. TRIAL REGISTRATION The trial was retrospectively registered under NCT05466630 in clinicaltrials.gov on July 15 2022.
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Affiliation(s)
- Martial Kassi N'Djetchi
- Laboratory of Biodiversity and Ecosystem Management, Jean Lorougnon Guédé University, Daloa, Côte d'Ivoire
| | - Oumou Camara
- National Program for Neglected Tropical Disease Control, Patient Management, Ministry of Health, Conakry, Guinea
| | - Mathurin Koffi
- Laboratory of Biodiversity and Ecosystem Management, Jean Lorougnon Guédé University, Daloa, Côte d'Ivoire
| | - Mamadou Camara
- National Program for Neglected Tropical Disease Control, Patient Management, Ministry of Health, Conakry, Guinea
| | - Dramane Kaba
- Trypanosomosis Research Unit, Pierre Richet Institute, Bouaké, Côte d'Ivoire
| | - Jacques Kaboré
- International Research and Development Centre on Livestock in Subhumid Zones, Bobo-Dioulasso, Burkina Faso
| | - Alkali Tall
- National Program for Malaria Control, Conakry, Guinea
| | - Brice Rotureau
- Parasitology Unit, Institut Pasteur de Guinée, Conakry, Guinea
| | - Lucy Glover
- Trypanosome Molecular Biology Unit, Department of Parasites and Insect Vectors, Pasteur Institute, Paris Cité University, Paris, France
| | - Mélika Barkissa Traoré
- Laboratory of Biodiversity and Ecosystem Management, Jean Lorougnon Guédé University, Daloa, Côte d'Ivoire
| | - Minayegninrin Koné
- Laboratory of Biodiversity and Ecosystem Management, Jean Lorougnon Guédé University, Daloa, Côte d'Ivoire
| | - Bamoro Coulibaly
- Trypanosomosis Research Unit, Pierre Richet Institute, Bouaké, Côte d'Ivoire
| | - Guy Pacome Adingra
- Trypanosomosis Research Unit, Pierre Richet Institute, Bouaké, Côte d'Ivoire
| | - Aissata Soumah
- National Program for Neglected Tropical Disease Control, Patient Management, Ministry of Health, Conakry, Guinea
| | - Mohamed Gassama
- National Program for Neglected Tropical Disease Control, Patient Management, Ministry of Health, Conakry, Guinea
| | - Abdoulaye Dansy Camara
- National Program for Neglected Tropical Disease Control, Patient Management, Ministry of Health, Conakry, Guinea
| | | | - Aïssata Camara
- Parasitology Unit, Institut Pasteur de Guinée, Conakry, Guinea
| | - Salimatou Boiro
- Parasitology Unit, Institut Pasteur de Guinée, Conakry, Guinea
| | - Elena Perez Anton
- Trypanosome Molecular Biology Unit, Department of Parasites and Insect Vectors, Pasteur Institute, Paris Cité University, Paris, France
| | | | - Nick Van Reet
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Bruno Bucheton
- National Program for Neglected Tropical Disease Control, Patient Management, Ministry of Health, Conakry, Guinea
- Intertryp, IRD-CIRAD-University of Montpellier, Montpellier, France
| | - Vincent Jamonneau
- Trypanosomosis Research Unit, Pierre Richet Institute, Bouaké, Côte d'Ivoire
- Intertryp, IRD-CIRAD-University of Montpellier, Montpellier, France
| | - Jean-Mathieu Bart
- National Program for Neglected Tropical Disease Control, Patient Management, Ministry of Health, Conakry, Guinea
- Intertryp, IRD-CIRAD-University of Montpellier, Montpellier, France
| | - Philippe Solano
- Intertryp, IRD-CIRAD-University of Montpellier, Montpellier, France
| | - Sylvain Biéler
- Foundation for Innovative New Diagnostics, Geneva, Switzerland
| | - Veerle Lejon
- Intertryp, IRD-CIRAD-University of Montpellier, Montpellier, France.
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Mikkelsen JH, Stødkilde K, Jensen MP, Hansen AG, Wu Q, Lorentzen J, Graversen JH, Andersen GR, Fenton RA, Etzerodt A, Thiel S, Andersen CBF. Trypanosoma brucei Invariant Surface Glycoprotein 75 Is an Immunoglobulin Fc Receptor Inhibiting Complement Activation and Antibody-Mediated Cellular Phagocytosis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:1334-1344. [PMID: 38391367 DOI: 10.4049/jimmunol.2300862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 02/05/2024] [Indexed: 02/24/2024]
Abstract
Various subspecies of the unicellular parasite Trypanosoma brucei cause sleeping sickness, a neglected tropical disease affecting millions of individuals and domestic animals. Immune evasion mechanisms play a pivotal role in parasite survival within the host and enable the parasite to establish a chronic infection. In particular, the rapid switching of variant surface glycoproteins covering a large proportion of the parasite's surface enables the parasite to avoid clearance by the adaptive immune system of the host. In this article, we present the crystal structure and discover an immune-evasive function of the extracellular region of the T. brucei invariant surface gp75 (ISG75). Structural analysis determined that the ISG75 ectodomain is organized as a globular head domain and a long slender coiled-coil domain. Subsequent ligand screening and binding analysis determined that the head domain of ISG75 confers interaction with the Fc region of all subclasses of human IgG. Importantly, the ISG75-IgG interaction strongly inhibits both activation of the classical complement pathway and Ab-dependent cellular phagocytosis by competing with C1q and host cell FcγR CD32. Our data reveal a novel immune evasion mechanism of T. brucei, with ISG75 able to inactivate the activities of Abs recognizing the parasite surface proteins.
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Affiliation(s)
| | | | | | | | - Qi Wu
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Josefine Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Jonas Heilskov Graversen
- Department of Cancer and Inflammation, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Gregers Rom Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | - Anders Etzerodt
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Steffen Thiel
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Vourchakbé J, Tiofack AAZ, Kante ST, Barka PA, Simo G. Prevalence of pathogenic trypanosome species in naturally infected cattle of three sleeping sickness foci of the south of Chad. PLoS One 2022; 17:e0279730. [PMID: 36584086 PMCID: PMC9803169 DOI: 10.1371/journal.pone.0279730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 12/14/2022] [Indexed: 12/31/2022] Open
Abstract
Although a diversity of trypanosome species have been detected in various animal taxa from human African trypanosomosis (HAT) foci, cattle trypanosomosis has not been addressed in HAT foci of west and central African countries including Chad. This study aimed to determine the prevalence of pathogenic trypanosome species in cattle from three HAT foci of the south of Chad. Blood samples were collected from 1466 randomly selected cattle from HAT foci of Mandoul, Maro, and Moïssala in the south of Chad. For each animal, the sex, age and body condition were recorded. Rapid diagnostic test (RDT) was used to search Trypanosoma brucei gambiense antibodies while the capillary tube centrifugation (CTC) test and PCR-based methods enabled to detect and identify trypanosome species. From the 1466 cattle, 45 (3.1%) were positive to RDT. The prevalence of trypanosome infections revealed by CTC and PCR-based method were respectively 2.7% and 11.1%. Trypanosomes of the subgenus Trypanozoon were dominant (6.5%) followed by T. congolense savannah (2.9%), T. congolense forest (2.5%) and T. vivax (0.8%). No animal was found with DNA of human infective trypanosome (T. b. gambiense). The overall prevalence of trypanosome infections was significantly higher in animal from the Maro HAT focus (13.8%) than those from Mandoul (11.1%) and Moïssala HAT foci (8.0%). This prevalence was also significantly higher in animal having poor body condition (77.5%) than those with medium (11.2%) and good (0.5%) body condition. The overall prevalence of single and mixed infections were respectively 9.4% and 1.6%. This study revealed natural infections of several pathogenic trypanosome species in cattle from different HAT foci of Chad. It showed similar transmission patterns of these trypanosome species and highlighted the need of developing control strategies for animal African trypanosomosis (AAT) with the overarching goal of improving animal health and the economy of smallholder farmers.
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Affiliation(s)
- Joël Vourchakbé
- Department of Biological Science, Faculty of Science and Technology, University of Doba, Doba, Chad
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Arnol Auvaker Zebaze Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Sartrien Tagueu Kante
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Padja Abdoul Barka
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
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Pereira T, Lousada M. Psychometric Properties of Standardized Instruments that are Used to Measure Pragmatic Intervention Effects in Children with Developmental Language Disorder: A Systematic Review. J Autism Dev Disord 2022; 53:1764-1780. [PMID: 35201565 DOI: 10.1007/s10803-022-05481-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2022] [Indexed: 11/27/2022]
Abstract
This review aimed to analyze the psychometric properties of standardized instruments that are used to measure pragmatic intervention effects in children with developmental language disorder. Following PRISMA structure, a comprehensive literature research was conducted in five electronic indexing databases: Central, PubMed, Medline, Web of Science and Scopus. Six studies between 2005 and 2019 were included and seven standardized instruments have been analyzed. All instruments present some evidence of validity and reliability, but none reported responsiveness. The instruments reviewed were not used for their original purpose, which may explain the results. The small number of studies prevent drawing clear conclusions. Future studies should focus on appropriate, valid, reliable, and responsive measures. Research focusing on psychometric properties is crucial, mostly about responsiveness.
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Affiliation(s)
- Tatiana Pereira
- Center for Health Technology and Services Research (CINTESIS.UA), Aveiro, Portugal.
- Center of Linguistics of the University of Lisbon (CLUL), Lisbon, Portugal.
- University of Aveiro, Aveiro, Portugal.
- University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Marisa Lousada
- Center for Health Technology and Services Research (CINTESIS.UA), Aveiro, Portugal
- Center of Linguistics of the University of Lisbon (CLUL), Lisbon, Portugal
- School of Health Sciences (ESSUA), University of Aveiro, Aveiro, Portugal
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Franco JR, Cecchi G, Paone M, Diarra A, Grout L, Kadima Ebeja A, Simarro PP, Zhao W, Argaw D. The elimination of human African trypanosomiasis: Achievements in relation to WHO road map targets for 2020. PLoS Negl Trop Dis 2022; 16:e0010047. [PMID: 35041668 PMCID: PMC8765662 DOI: 10.1371/journal.pntd.0010047] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 12/02/2021] [Indexed: 11/19/2022] Open
Abstract
Background In the 20th century, epidemics of human African trypanosomiasis (HAT) ravaged communities in a number of African countries. The latest surge in disease transmission was recorded in the late 1990s, with more than 35,000 cases reported annually in 1997 and 1998. In 2013, after more than a decade of sustained control efforts and steady progress, the World Health Assembly resolved to target the elimination of HAT as a public health problem by 2020. We report here on recent progress towards this goal. Methodology/principal findings With 992 and 663 cases reported in 2019 and 2020 respectively, the first global target was amply achieved (i.e. fewer than 2,000 HAT cases/year). Areas at moderate or higher risk of HAT, where more than 1 case/10,000 people/year are reported, shrunk to 120,000 km2 for the five-year period 2016–2020. This reduction of 83% from the 2000–2004 baseline (i.e. 709,000 km2) is slightly below the target (i.e. 90% reduction). As a result, the second global target for HAT elimination as a public health problem cannot be considered fully achieved yet. The number of health facilities able to diagnose and treat HAT expanded (+9.6% compared to a 2019 survey), thus reinforcing the capacity for passive detection and improving epidemiological knowledge of the disease. Active surveillance for gambiense HAT was sustained. In particular, 2.8 million people were actively screened in 2019 and 1.6 million in 2020, the decrease in 2020 being mainly caused by COVID-19-related restrictions. Togo and Côte d’Ivoire were the first countries to be validated for achieving elimination of HAT as a public health problem at the national level; applications from three additional countries are under review by the World Health Organization (WHO). Conclusions/significance The steady progress towards the elimination of HAT is a testament to the power of multi-stakeholder commitment and coordination. At the end of 2020, the World Health Assembly endorsed a new road map for 2021–2030 that set new bold targets for neglected tropical diseases. While rhodesiense HAT remains among the diseases targeted for elimination as a public health problem, gambiense HAT is targeted for elimination of transmission. The goal for gambiense HAT is expected to be particularly arduous, as it might be hindered by cryptic reservoirs and a number of other challenges (e.g. further integration of HAT surveillance and control into national health systems, availability of skilled health care workers, development of more effective and adapted tools, and funding for and coordination of elimination efforts). Human African trypanosomiasis (HAT) is a lethal neglected tropical disease (NTD) transmitted by the bite of infected tsetse flies. The disease is also known as “sleeping sickness”. During the 20th century it caused enormous suffering in the endemic areas in sub-Saharan Africa. HAT transmission last soared in the late 1990s, triggering a renewed, coordinated and very successful control effort. In this paper, we present achievements towards HAT elimination, with a focus on the WHO road map targets for 2020. In particular, reported cases continue to decline, from over 30,000 cases per year at the turn of the century to 663 cases in 2020. Despite the impact of the COVID-19 pandemic, HAT surveillance was largely sustained, and the network of health facilities able to diagnose and treat the disease further expanded. Looking to the future, the World Health Organization (WHO) set bold new targets for HAT in its 2021–2030 road map for NTDs, namely: the elimination of transmission of gambiense HAT, which occurs in western and central Africa, and the elimination as a public health problem of rhodesiense HAT, which is found in eastern and southern Africa. The strong commitment of national health authorities and the international community will be essential if these goals are to be achieved.
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Affiliation(s)
- Jose R. Franco
- World Health Organization, Control of Neglected Tropical Diseases, Prevention Treatment and Care, Geneva, Switzerland
- * E-mail:
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Massimo Paone
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Abdoulaye Diarra
- World Health Organization, Regional Office for Africa, Communicable Disease Unit, Brazzaville, Congo
| | - Lise Grout
- World Health Organization, Control of Neglected Tropical Diseases, Prevention Treatment and Care, Geneva, Switzerland
| | - Augustin Kadima Ebeja
- World Health Organization, Regional Office for Africa, Communicable Disease Unit, Brazzaville, Congo
| | - Pere P. Simarro
- Consultant, World Health Organization, Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, Geneva, Switzerland
| | - Weining Zhao
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Daniel Argaw
- World Health Organization, Control of Neglected Tropical Diseases, Prevention Treatment and Care, Geneva, Switzerland
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Magez S, Li Z, Nguyen HTT, Pinto Torres JE, Van Wielendaele P, Radwanska M, Began J, Zoll S, Sterckx YGJ. The History of Anti-Trypanosome Vaccine Development Shows That Highly Immunogenic and Exposed Pathogen-Derived Antigens Are Not Necessarily Good Target Candidates: Enolase and ISG75 as Examples. Pathogens 2021; 10:pathogens10081050. [PMID: 34451514 PMCID: PMC8400590 DOI: 10.3390/pathogens10081050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/02/2021] [Accepted: 08/10/2021] [Indexed: 12/02/2022] Open
Abstract
Salivarian trypanosomes comprise a group of extracellular anthroponotic and zoonotic parasites. The only sustainable method for global control of these infection is through vaccination of livestock animals. Despite multiple reports describing promising laboratory results, no single field-applicable solution has been successful so far. Conventionally, vaccine research focusses mostly on exposed immunogenic antigens, or the structural molecular knowledge of surface exposed invariant immunogens. Unfortunately, extracellular parasites (or parasites with extracellular life stages) have devised efficient defense systems against host antibody attacks, so they can deal with the mammalian humoral immune response. In the case of trypanosomes, it appears that these mechanisms have been perfected, leading to vaccine failure in natural hosts. Here, we provide two examples of potential vaccine candidates that, despite being immunogenic and accessible to the immune system, failed to induce a functionally protective memory response. First, trypanosomal enolase was tested as a vaccine candidate, as it was recently characterized as a highly conserved enzyme that is readily recognized during infection by the host antibody response. Secondly, we re-addressed a vaccine approach towards the Invariant Surface Glycoprotein ISG75, and showed that despite being highly immunogenic, trypanosomes can avoid anti-ISG75 mediated parasitemia control.
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Affiliation(s)
- Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Department of Biochemistry and Microbiology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
- Correspondence:
| | - Zeng Li
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
| | - Hang Thi Thu Nguyen
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Department of Biochemistry and Microbiology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
| | - Joar Esteban Pinto Torres
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
| | - Pieter Van Wielendaele
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
- Department of Biomedical Molecular Biology, Ghent University, Technologiepark Zwijnaarde 71, 9000 Ghent, Belgium
| | - Jakub Began
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo Namesti 2, 16610 Prague 6, Czech Republic; (J.B.); (S.Z.)
| | - Sebastian Zoll
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo Namesti 2, 16610 Prague 6, Czech Republic; (J.B.); (S.Z.)
| | - Yann G.-J. Sterckx
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
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Bharadwaj M, Bengtson M, Golverdingen M, Waling L, Dekker C. Diagnosing point-of-care diagnostics for neglected tropical diseases. PLoS Negl Trop Dis 2021; 15:e0009405. [PMID: 34138846 PMCID: PMC8211285 DOI: 10.1371/journal.pntd.0009405] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Inadequate and nonintegrated diagnostics are the Achilles' heel of global efforts to monitor, control, and eradicate neglected tropical diseases (NTDs). While treatment is often available, NTDs are endemic among marginalized populations, due to the unavailability or inadequacy of diagnostic tests that cause empirical misdiagnoses. The need of the hour is early diagnosis at the point-of-care (PoC) of NTD patients. Here, we review the status quo of PoC diagnostic tests and practices for all of the 24 NTDs identified in the World Health Organization's (WHO) 2021-2030 roadmap, based on their different diagnostic requirements. We discuss the capabilities and shortcomings of current diagnostic tests, identify diagnostic needs, and formulate prerequisites of relevant PoC tests. Next to technical requirements, we stress the importance of availability and awareness programs for establishing PoC tests that fit endemic resource-limited settings. Better understanding of NTD diagnostics will pave the path for setting realistic goals for healthcare in areas with minimal resources, thereby alleviating the global healthcare burden.
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Affiliation(s)
- Mitasha Bharadwaj
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | - Michel Bengtson
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | - Mirte Golverdingen
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | - Loulotte Waling
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, The Netherlands
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Vourchakbé J, Tiofack ZAA, Kante TS, Mpoame M, Simo G. Molecular identification of Trypanosoma brucei gambiense in naturally infected pigs, dogs and small ruminants confirms domestic animals as potential reservoirs for sleeping sickness in Chad. ACTA ACUST UNITED AC 2020; 27:63. [PMID: 33206595 PMCID: PMC7673351 DOI: 10.1051/parasite/2020061] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 11/02/2020] [Indexed: 12/03/2022]
Abstract
Human African trypanosomiasis (HAT) has been targeted for zero transmission to humans by 2030. Animal reservoirs of gambiense-HAT could jeopardize these elimination goals. This study was undertaken to identify potential host reservoirs for Trypanosoma brucei gambiense by detecting its natural infections in domestic animals of Chadian HAT foci. Blood samples were collected from 267 goats, 181 sheep, 154 dogs, and 67 pigs. Rapid diagnostic test (RDT) and capillary tube centrifugation (CTC) were performed to search for trypanosomes. DNA was extracted from the buffy coat, and trypanosomes of the subgenus Trypanozoon as well as T. b. gambiense were identified by PCR. Of 669 blood samples, 19.4% were positive by RDT and 9.0% by CTC. PCR revealed 150 animals (22.4%) with trypanosomes belonging to Trypanozoon, including 18 (12%) T. b. gambiense. This trypanosome was found in all investigated animal species and all HAT foci. Between animal species or villages, no significant differences were observed in the number of animals harboring T. b. gambiense DNA. Pigs, dogs, sheep and goats appeared to be potential reservoir hosts for T. b. gambiense in Chad. The identification of T. b. gambiense in all animal species of all HAT foci suggests that these animals should be considered when designing new control strategies for sustainable elimination of HAT. Investigations aiming to decrypt their specific role in each epidemiological setting are important to achieve zero transmission of HAT.
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Affiliation(s)
| | - Zebaze Arnol Auvaker Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67 Dschang, Cameroon
| | - Tagueu Sartrien Kante
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67 Dschang, Cameroon
| | - Mbida Mpoame
- Laboratory of Applied Biology and Ecology (LABEA), Department of Animal Biology, Faculty of Science, University of Dschang, PO Box 067 Dschang, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67 Dschang, Cameroon
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Akazue PI, Ebiloma GU, Ajibola O, Isaac C, Onyekwelu K, Ezeh CO, Eze AA. Sustainable Elimination (Zero Cases) of Sleeping Sickness: How Far Are We from Achieving This Goal? Pathogens 2019; 8:E135. [PMID: 31470522 PMCID: PMC6789789 DOI: 10.3390/pathogens8030135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 08/26/2019] [Accepted: 08/26/2019] [Indexed: 01/02/2023] Open
Abstract
The recent massive reduction in the numbers of fresh Human African Trypanosomiasis (HAT) infection has presented an opportunity for the global elimination of this disease. To prevent a possible resurgence, as was the case after the reduced transmission of the 1960s, surveillance needs to be sustained and the necessary tools for detection and treatment of cases need to be made available at the points of care. In this review, we examine the available resources and make recommendations for improvement to ensure the sustenance of the already achieved gains to keep the trend moving towards elimination.
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Affiliation(s)
- Pearl Ihuoma Akazue
- Department of Biochemistry, Faculty of Life Sciences, University of Benin, Benin City 300283, Nigeria
| | - Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK
| | - Olumide Ajibola
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul PO Box 273, The Gambia
| | - Clement Isaac
- Department of Zoology, Faculty of Life Sciences, Ambrose Alli University, Ekpoma 310101, Nigeria
| | - Kenechukwu Onyekwelu
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria
| | - Charles O Ezeh
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria
| | - Anthonius Anayochukwu Eze
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, University of Nigeria, Enugu Campus, Enugu 410001, Nigeria.
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Prospective evaluation of a rapid diagnostic test for Trypanosoma brucei gambiense infection developed using recombinant antigens. PLoS Negl Trop Dis 2018; 12:e0006386. [PMID: 29590116 PMCID: PMC5898764 DOI: 10.1371/journal.pntd.0006386] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 04/13/2018] [Accepted: 03/13/2018] [Indexed: 11/19/2022] Open
Abstract
Background Diagnosis and treatment are central elements of strategies to control Trypanosoma brucei gambiense human African trypanosomiasis (HAT). Serological screening is a key entry point in diagnostic algorithms. The Card Agglutination Test for Trypanosomiasis (CATT) has been the most widely used screening test for decades, despite a number of practical limitations that were partially addressed by the introduction of rapid diagnostic tests (RDTs). However, current RDTs are manufactured using native antigens, which are challenging to produce. Methodology/Principal findings The objective of this study was to evaluate the accuracy of a new RDT developed using recombinant antigens (SD BIOLINE HAT 2.0), in comparison with an RDT produced using native antigens (SD BIOLINE HAT) and CATT. A total of 57,632 individuals were screened in the Democratic Republic of the Congo, either passively at 10 health centres, or actively by 5 mobile teams, and 260 HAT cases were confirmed by parasitology. The highest sensitivity was achieved with the SD BIOLINE HAT 2.0 (71.2%), followed by CATT (62.5%) and the SD BIOLINE HAT (59.0%). The most specific test was CATT (99.2%), while the specificity of the SD BIOLINE HAT and SD BIOLINE HAT 2.0 were 98.9% and 98.1%, respectively. Sensitivity of the tests was lower than previously reported, as they identified cases from partially overlapping sub-populations. All three tests were significantly more sensitive in passive than in active screening. Combining two or three tests resulted in a markedly increased sensitivity: When the SD BIOLINE HAT was combined with the SD BIOLINE HAT 2.0, sensitivity reached 98.4% in passive and 83.0% in active screening. Conclusions/Significance The recombinant antigen-based RDT was more sensitive than, and as specific as, the SD BIOLINE HAT. It was as sensitive as, but slightly less specific than CATT. While the practicality and cost-effectiveness of algorithms including several screening tests would need to be investigated, using two or more tests appears to enhance sensitivity of diagnostic algorithms, although some decrease in specificity is observed as well. Sleeping sickness, or human African trypanosomiasis (HAT), is a neglected tropical disease that represents a risk to more than seventy million people in Sub-Saharan Africa. Most cases are caused by infection with Trypanosoma brucei gambiense. Diagnosis of HAT relies on the identification of suspected cases by serological methods, which include recently developed rapid diagnostic tests (RDTs). Current RDTs are produced using native antigens that are purified from live parasites in a laborious and dangerous process. The objective of this study was to evaluate the performance of a new RDT made using recombinant antigens, by screening people in fifteen endemic sites in the Democratic Republic of the Congo. The new RDT was found to be more sensitive than, and as specific as, the reference RDT made using native antigens. It was also more sensitive than CATT, a serological test that has been widely used for decades. While one third of HAT cases were correctly diagnosed by all tests, the other cases were only identified by one or two of the tests. In order to enhance case detection and accelerate elimination of HAT, there may be a need to explore diagnostic strategies that combine two or more screening tests.
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Matovu E, Kitibwa A, Picado A, Biéler S, Bessell PR, Ndung'u JM. Serological tests for gambiense human African trypanosomiasis detect antibodies in cattle. Parasit Vectors 2017; 10:546. [PMID: 29100526 PMCID: PMC5670715 DOI: 10.1186/s13071-017-2487-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/19/2017] [Indexed: 11/23/2022] Open
Abstract
Background Serological tests for gambiense human African trypanosomiasis (gHAT) detect antibodies to antigens on the cell surface of bloodstream trypanosomes. As trypanosomes that cause animal African trypanosomiasis (AAT) also express related antigens, we have evaluated two rapid diagnostic tests (RDTs) on cattle in trypanosomiasis endemic and non-endemic regions, to determine whether gHAT serological tests could also be used to screen for AAT. Methods Two RDTs, 1G RDT, made with native antigens, and p2G RDT, made with recombinant antigens, were tested on 121 cattle in a trypanosomiasis-free region, and on 312 cattle from a rhodesiense HAT and AAT endemic region. A subset of samples from the endemic region were also tested with two immune trypanolysis (TL) tests. The sensitivity of the tests was estimated by evaluating the result of the RDT on samples that were positive by both microscopy and internal transcribed spacer (ITS) PCR, whilst specificity was the result of the RDT on samples that were negative by ITS PCR and microscopy, and others from the non-endemic region. Results The specificity of the p2G RDT on cattle from the non-endemic region was 97.5% (95% CI: 93.0–99.2%), compared to only 57.9% (95% CI: 48.9–66.3%) for 1G RDT. The specificities of 1G RDT, p2G RDT and TL on endemic control cattle were 14.6% (95% CI: 9.7–21.5%), 22.6% (95% CI: 16.4–30.3%) and 68.3% (95% CI: 59.6–75.9%), respectively. The sensitivities of the tests on trypanosome positive samples were 85.1% (95% CI: 79.1–89.7%), 89.1% (95% CI: 83.7–93.0%) and 59.3% (95% CI: 51.8–66.4%), respectively. Among the same samples, 51.7% were positive by both TL and the 1G RDT. Conclusions These serological tests detect cross-reacting antibodies in cattle. The p2G RDT based on recombinant antigens had a high specificity in a non-endemic region, while the 1G RDT had a lower specificity, suggesting cross-reactivity with other pathogens. Electronic supplementary material The online version of this article (10.1186/s13071-017-2487-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Enock Matovu
- College of Veterinary Medicine, Animal Resources and Biosecurity (COVAB), Makerere University, Kampala, Uganda.
| | - Annah Kitibwa
- College of Veterinary Medicine, Animal Resources and Biosecurity (COVAB), Makerere University, Kampala, Uganda
| | - Albert Picado
- Foundation for Innovative New Diagnostics (FIND), Campus Biotech, Chemin des Mines, Geneva, Switzerland
| | - Sylvain Biéler
- Foundation for Innovative New Diagnostics (FIND), Campus Biotech, Chemin des Mines, Geneva, Switzerland
| | | | - Joseph Mathu Ndung'u
- Foundation for Innovative New Diagnostics (FIND), Campus Biotech, Chemin des Mines, Geneva, Switzerland
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