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Machado H, Temudo A, Niz MD. The lymphatic system favours survival of a unique T. brucei population. Biol Open 2023; 12:bio059992. [PMID: 37870927 PMCID: PMC10651106 DOI: 10.1242/bio.059992] [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: 04/28/2023] [Accepted: 10/13/2023] [Indexed: 10/25/2023] Open
Abstract
Trypanosoma brucei colonise and multiply in the blood vasculature, as well as in various organs of the host's body. Lymph nodes have been previously shown to harbour large numbers of parasites, and the lymphatic system has been proposed as a key site that allows T. brucei distribution through, and colonization of the mammalian body. However, visualization of host-pathogen interactions in the lymphatic system has never captured dynamic events with high spatial and temporal resolution throughout infection. In our work, we used a mixture of tools including intravital microscopy and ex vivo imaging to study T. brucei distribution in 20 sets of lymph nodes. We demonstrate that lymph node colonization by T. brucei is different across lymph node sets, with the most heavily colonised being the draining lymph nodes of main tissue reservoirs: the gonadal white adipose tissue and pancreas. Moreover, we show that the lymphatic vasculature is a pivotal site for parasite dispersal, and altering this colonization by blocking LYVE-1 is detrimental for parasite survival. Additionally, parasites within the lymphatic vasculature have unique morphological and behavioural characteristics, different to those found in the blood, demonstrating that across both types of vasculature, these environments are physically separated. Finally, we demonstrate that the lymph nodes and the lymphatic vasculature undergo significant alterations during T. brucei infection, resulting in oedema throughout the host's body.
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Affiliation(s)
- Henrique Machado
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - António Temudo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
- Bioimaging Unit, Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Mariana De Niz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
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Desquesnes M, Gonzatti M, Sazmand A, Thévenon S, Bossard G, Boulangé A, Gimonneau G, Truc P, Herder S, Ravel S, Sereno D, Jamonneau V, Jittapalapong S, Jacquiet P, Solano P, Berthier D. A review on the diagnosis of animal trypanosomoses. Parasit Vectors 2022; 15:64. [PMID: 35183235 PMCID: PMC8858479 DOI: 10.1186/s13071-022-05190-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/01/2022] [Indexed: 01/07/2023] Open
Abstract
This review focuses on the most reliable and up-to-date methods for diagnosing trypanosomoses, a group of diseases of wild and domestic mammals, caused by trypanosomes, parasitic zooflagellate protozoans mainly transmitted by insects. In Africa, the Americas and Asia, these diseases, which in some cases affect humans, result in significant illness in animals and cause major economic losses in livestock. A number of pathogens are described in this review, including several Salivarian trypanosomes, such as Trypanosoma brucei sspp. (among which are the agents of sleeping sickness, the human African trypanosomiasis [HAT]), Trypanosoma congolense and Trypanosoma vivax (causing “Nagana” or animal African trypanosomosis [AAT]), Trypanosoma evansi (“Surra”) and Trypanosoma equiperdum (“Dourine”), and Trypanosoma cruzi, a Stercorarian trypanosome, etiological agent of the American trypanosomiasis (Chagas disease). Diagnostic methods for detecting zoonotic trypanosomes causing Chagas disease and HAT in animals, as well as a diagnostic method for detecting animal trypanosomes in humans (the so-called “atypical human infections by animal trypanosomes” [a-HT]), including T. evansi and Trypanosoma lewisi (a rat parasite), are also reviewed. Our goal is to present an integrated view of the various diagnostic methods and techniques, including those for: (i) parasite detection; (ii) DNA detection; and (iii) antibody detection. The discussion covers various other factors that need to be considered, such as the sensitivity and specificity of the various diagnostic methods, critical cross-reactions that may be expected among Trypanosomatidae, additional complementary information, such as clinical observations and epizootiological context, scale of study and logistic and cost constraints. The suitability of examining multiple specimens and samples using several techniques is discussed, as well as risks to technicians, in the context of specific geographical regions and settings. This overview also addresses the challenge of diagnosing mixed infections with different Trypanosoma species and/or kinetoplastid parasites. Improving and strengthening procedures for diagnosing animal trypanosomoses throughout the world will result in a better control of infections and will significantly impact on “One Health,” by advancing and preserving animal, human and environmental health.
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Bessell PR, Lumbala C, Lutumba P, Baloji S, Biéler S, Ndung'u JM. Cost-effectiveness of using a rapid diagnostic test to screen for human African trypanosomiasis in the Democratic Republic of the Congo. PLoS One 2018; 13:e0204335. [PMID: 30240406 PMCID: PMC6150526 DOI: 10.1371/journal.pone.0204335] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 09/06/2018] [Indexed: 11/19/2022] Open
Abstract
New rapid diagnostic tests (RDTs) for screening human African trypanosomiasis (HAT) have been introduced as alternatives to the card agglutination test for trypanosomiasis (CATT). One brand of RDT, the SD BIOLINE HAT RDT has been shown to have lower specificity but higher sensitivity than CATT, so to make a rational choice between screening strategies, a cost-effectiveness analysis is a key element. In this paper we estimate the relative cost-effectiveness of CATT and the RDT when implemented in the Democratic Republic of the Congo (DRC). Data on the epidemiological parameters and costs were collected as part of a larger study. These data were used to model three different diagnostic algorithms in mobile teams and fixed health facilities, and the relative cost-effectiveness was measured as the average cost per case diagnosed. In both fixed facilities and mobile teams, screening of participants using the SD BIOLINE HAT RDT followed by parasitological confirmation had a lower cost-effectiveness ratio than in algorithms using CATT. Algorithms using the RDT were cheaper by 112.54 (33.2%) and 88.54 (32.92%) US dollars per case diagnosed in mobile teams and fixed health facilities respectively, when compared with algorithms using CATT. Sensitivity analysis demonstrated that these conclusions were robust to a number of assumptions, and that the results can be scaled to smaller or larger facilities, and a range of prevalences. The RDT was the most cost-effective screening test in all realistic scenarios and detected more cases than CATT. Thus, on this basis, the SD BIOLINE HAT RDT could be considered as the most cost-effective option for use in routine screening for HAT in the DRC.
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Affiliation(s)
| | - Crispin Lumbala
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, République Démocratique du Congo
- Global Health Institute, University of Antwerp, Antwerp, Belgium
| | - Pascal Lutumba
- Faculty of Medicine, University of Kinshasa, Kinshasa, République Démocratique du Congo
- Institute National de Recherche Biomédicale, Kinshasa, République Démocratique du Congo
| | - Sylvain Baloji
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, République Démocratique du Congo
| | - Sylvain Biéler
- Foundation for Innovative New Diagnostics (FIND), Campus Biotech, 9 Chemin des Mines, Geneva, Switzerland
| | - Joseph M. Ndung'u
- Foundation for Innovative New Diagnostics (FIND), Campus Biotech, 9 Chemin des Mines, Geneva, Switzerland
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Cunningham LJ, Lingley JK, Haines LR, Ndung’u JM, Torr SJ, Adams ER. Illuminating the Prevalence of Trypanosoma brucei s.l. in Glossina Using LAMP as a Tool for Xenomonitoring. PLoS Negl Trop Dis 2016; 10:e0004441. [PMID: 26890882 PMCID: PMC4758712 DOI: 10.1371/journal.pntd.0004441] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/16/2016] [Indexed: 11/23/2022] Open
Abstract
Background As the reality of eliminating human African trypanosomiasis (HAT) by 2020 draws closer, the need to detect and identify the remaining areas of transmission increases. Here, we have explored the feasibility of using commercially available LAMP kits, designed to detect the Trypanozoon group of trypanosomes, as a xenomonitoring tool to screen tsetse flies for trypanosomes to be used in future epidemiological surveys. Methods and Findings The DNA extraction method was simplified and worked with the LAMP kits to detect a single positive fly when pooled with 19 negative flies, and the absolute lowest limit of detection that the kits were able to work at was the equivalent of 0.1 trypanosome per ml. The DNA from Trypanosoma brucei brucei could be detected six days after the fly had taken a blood meal containing dead trypanosomes, and when confronted with a range of non-target species, from both laboratory-reared flies and wild-caught flies, the kits showed no evidence of cross-reacting. Conclusion We have shown that it is possible to use a simplified DNA extraction method in conjunction with the pooling of tsetse flies to decrease the time it would take to screen large numbers of flies for the presence of Trypanozoon trypanosomes. The use of commercially-available LAMP kits provides a reliable and highly sensitive tool for xenomonitoring and identifying potential sleeping sickness transmission sites. Recent control efforts have reduced the global incidence of Gambiense human African trypanosomiasis (HAT) to <5,000 cases per year, strengthening the prospect of eliminating the disease as a public health problem by 2020. To meet this goal, new methods for identifying transmission must be explored to provide a cost-effective way of identifying hotspots and areas of re-emergence; commercial loop-mediated isothermal amplification (LAMP) kits that detect the trypanosome subgenus, responsible for the two forms of sleeping sickness, have been developed. The LAMP kits were tested to assess their sensitivity, specificity and suitability as a method of screening the vector of the disease, Glossina, for Trypanozoon infection, in xenomonitoring campaigns. A simplified DNA extraction process that worked in conjunction with the LAMP kits on pooled samples demonstrated a faster method of processing large numbers of flies compared to other molecular tools. The kits performed well in our experiments and demonstrated the ability of detecting low levels of target DNA, equivalent to 0.1 trypanosome per ml. The lack of cross reaction with non-target species of trypanosomes makes the kits reliable in so far as they will only react with the Trypanozoon group of parasites of which the two human forms of the disease belong, however, further species-specific tests would need to be undertaken to identify HAT areas on selected samples.
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Affiliation(s)
- Lucas J. Cunningham
- Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail:
| | - Jessica K. Lingley
- Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Lee R. Haines
- Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Joseph M. Ndung’u
- Neglected Tropical Disease Programme, Foundation for Innovation New Diagnostics (FIND), Geneva, Switzerland
| | - Stephen J. Torr
- Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Emily R. Adams
- Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
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Sutherland CS, Yukich J, Goeree R, Tediosi F. A literature review of economic evaluations for a neglected tropical disease: human African trypanosomiasis ("sleeping sickness"). PLoS Negl Trop Dis 2015; 9:e0003397. [PMID: 25654605 PMCID: PMC4318581 DOI: 10.1371/journal.pntd.0003397] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Human African trypanosomiasis (HAT) is a disease caused by infection with the parasite Trypanosoma brucei gambiense or T. b. rhodesiense. It is transmitted to humans via the tsetse fly. Approximately 70 million people worldwide were at risk of infection in 1995, and approximately 20,000 people across Africa are infected with HAT. The objective of this review was to identify existing economic evaluations in order to summarise cost-effective interventions to reduce, control, or eliminate the burden of HAT. The studies included in the review were compared and critically appraised in order to determine if there were existing standardised methods that could be used for economic evaluation of HAT interventions or if innovative methodological approaches are warranted. A search strategy was developed using keywords and was implemented in January 2014 in several databases. The search returned a total of 2,283 articles. After two levels of screening, a total of seven economic evaluations were included and underwent critical appraisal using the Scottish Intercollegiate Guidelines Network (SIGN) Methodology Checklist 6: Economic Evaluations. Results from the existing studies focused on the cost-effectiveness of interventions for the control and reduction of disease transmission. Modelling was a common method to forecast long-term results, and publications focused on interventions by category, such as case detection, diagnostics, drug treatments, and vector control. Most interventions were considered cost-effective based on the thresholds described; however, the current treatment, nifurtomix-eflornithine combination therapy (NECT), has not been evaluated for cost-effectiveness, and considerations for cost-effective strategies for elimination have yet to be completed. Overall, the current evidence highlights the main components that play a role in control; however, economic evaluations of HAT elimination strategies are needed to assist national decision makers, stakeholders, and key funders. These analyses would be of use, as HAT is currently being prioritized as a neglected tropical disease (NTD) to reach elimination by 2020.
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Affiliation(s)
- C. Simone Sutherland
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
| | - Joshua Yukich
- Department of Global Health Systems and Development, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana, United States of America
| | - Ron Goeree
- Programs for Assessment of Technology in Health (PATH) Research Institute, St. Joseph’s Healthcare Hamilton, Hamilton, Ontario, Canada
- Department of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, Ontario, Canada
| | - Fabrizio Tediosi
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Centre for Research on Health and Social Care Management (CERGAS), Università Bocconi, Milano, Italy
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Turner HC, Walker M, French MD, Blake IM, Churcher TS, Basáñez MG. Neglected tools for neglected diseases: mathematical models in economic evaluations. Trends Parasitol 2014; 30:562-70. [PMID: 25455565 DOI: 10.1016/j.pt.2014.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/01/2014] [Accepted: 10/07/2014] [Indexed: 12/27/2022]
Abstract
Despite many current interventions against neglected tropical diseases (NTDs) being highly cost-effective, new strategies are needed to reach the WHO's control and elimination goals. Here we argue for the importance of incorporating economic evaluations of new strategies in decisions regarding resource allocation. Such evaluation should ideally be conducted using dynamic transmission models that capture inherent nonlinearities in transmission and the indirect benefits ('herd effects') of interventions. A systematic review of mathematical models that have been used for economic analysis of interventions against the ten NTDs covered by the London Declaration reveals that only 16 out of 49 studies used dynamic transmission models, highlighting a fundamental--but addressable--gap in the evaluation of interventions against NTDs.
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Affiliation(s)
- Hugo C Turner
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK; Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK.
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK; Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK
| | - Michael D French
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK; Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK
| | - Isobel M Blake
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK; MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London W2 1PG, UK
| | - Thomas S Churcher
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK
| | - María-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK; Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK
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Hackett F, Berrang Ford L, Fèvre E, Simarro P. Incorporating scale dependence in disease burden estimates: the case of human African trypanosomiasis in Uganda. PLoS Negl Trop Dis 2014; 8:e2704. [PMID: 24551264 PMCID: PMC3923749 DOI: 10.1371/journal.pntd.0002704] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 01/03/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The WHO has established the disability-adjusted life year (DALY) as a metric for measuring the burden of human disease and injury globally. However, most DALY estimates have been calculated as national totals. We mapped spatial variation in the burden of human African trypanosomiasis (HAT) in Uganda for the years 2000-2009. This represents the first geographically delimited estimation of HAT disease burden at the sub-country scale. METHODOLOGY/PRINCIPAL FINDINGS Disability-adjusted life-year (DALY) totals for HAT were estimated based on modelled age and mortality distributions, mapped using Geographic Information Systems (GIS) software, and summarised by parish and district. While the national total burden of HAT is low relative to other conditions, high-impact districts in Uganda had DALY rates comparable to the national burden rates for major infectious diseases. The calculated average national DALY rate for 2000-2009 was 486.3 DALYs/100 000 persons/year, whereas three districts afflicted by rhodesiense HAT in southeastern Uganda had burden rates above 5000 DALYs/100 000 persons/year, comparable to national GBD 2004 average burden rates for malaria and HIV/AIDS. CONCLUSIONS/SIGNIFICANCE These results provide updated and improved estimates of HAT burden across Uganda, taking into account sensitivity to under-reporting. Our results highlight the critical importance of spatial scale in disease burden analyses. National aggregations of disease burden have resulted in an implied bias against highly focal diseases for which geographically targeted interventions may be feasible and cost-effective. This has significant implications for the use of DALY estimates to prioritize disease interventions and inform cost-benefit analyses.
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Affiliation(s)
- Finola Hackett
- Department of Geography, McGill University, Montreal, Quebec, Canada
| | - Lea Berrang Ford
- Department of Geography, McGill University, Montreal, Quebec, Canada
| | - Eric Fèvre
- Veterinary and Infectious Diseases, Institute of Infection and Global Health, University of Liverpool, Neston, United Kingdom
| | - Pere Simarro
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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Inogwabini BI, Leader-Williams N. Effects of epidemic diseases on the distribution of bonobos. PLoS One 2012; 7:e51112. [PMID: 23251431 PMCID: PMC3521019 DOI: 10.1371/journal.pone.0051112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 10/29/2012] [Indexed: 11/18/2022] Open
Abstract
This study examined how outbreaks and the occurrence of Anthrax, Ebola, Monkeypox and Trypanosomiasis may differentially affect the distribution of bonobos (Pan paniscus). Using a combination of mapping, Jaccard overlapping coefficients and binary regressions, the study determined how each disease correlated with the extent of occurrence of, and the areas occupied by, bonobos. Anthrax has only been reported to occur outside the range of bonobos and so was not considered further. Ebola, Monkeypox and Trypanosomiasis were each reported within the area of occupancy of bonobos. Their respective overlap coefficients were: J = 0.10; Q(α = 0.05) = 2.00 (odds ratios = 0.0001, 95% CI = 0.0057; Z = -19.41, significant) for Ebola; J = 1.00; Q(α = 0.05) = 24.0 (odds ratios = 1.504, 95% CI = 0.5066-2.6122) for Monkeypox; and, J = 0.33; Q(α = 0.05) = 11.5 (Z = 1.14, significant) for Trypanosomiasis. There were significant relationships for the presence and absence of Monkeypox and Trypanosomiasis and the known extent of occurrence of bonobos, based on the equations y = 0.2368Ln(x)+0.8006 (R(2) = 0.9772) and y = -0.2942Ln(x)+0.7155 (R(2) = 0.698), respectively. The positive relationship suggested that bonobos tolerated the presence of Monkeypox. In contrast, the significant negative coefficient suggested that bonobos were absent in areas where Trypanosomiasis is endemic. Our results suggest that large rivers may have prevented Ebola from spreading into the range of bonobos. Meanwhile, Trypanosomiasis has been recorded among humans within the area of occurrence of bonobos, and appears the most important disease in shaping the area of occupancy of bonobos within their overall extent of occupancy.
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Affiliation(s)
- Bila-Isia Inogwabini
- Durrell Institute for Conservation and Ecology, University of Kent, Canterbury, United Kingdom.
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Human african trypanosomiasis diagnosis in first-line health services of endemic countries, a systematic review. PLoS Negl Trop Dis 2012; 6:e1919. [PMID: 23209860 PMCID: PMC3510092 DOI: 10.1371/journal.pntd.0001919] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 10/09/2012] [Indexed: 11/19/2022] Open
Abstract
While the incidence of Human African Trypanosomiasis (HAT) is decreasing, the control approach is shifting from active population screening by mobile teams to passive case detection in primary care centers. We conducted a systematic review of the literature between 1970 and 2011 to assess which diagnostic tools are most suitable for use in first-line health facilities in endemic countries. Our search retrieved 16 different screening and confirmation tests for HAT. The thermostable format of the Card Agglutination Test for Trypanosomiasis (CATT test) was the most appropriate screening test. Lateral flow antibody detection tests could become alternative screening tests in the near future. Confirmation of HAT diagnosis still depends on visualizing the parasite in direct microscopy. All other currently available confirmation tests are either technically too demanding and/or lack sensitivity and thus rather inappropriate for use at health center level. Novel applications of molecular tests may have potential for use at district hospital level.
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Hasker E, Mpanya A, Makabuza J, Mbo F, Lumbala C, Kumpel J, Claeys Y, Kande V, Ravinetto R, Menten J, Lutumba P, Boelaert M. Treatment outcomes for human African Trypanosomiasis in the Democratic Republic of the Congo: analysis of routine program data from the world's largest sleeping sickness control program. Trop Med Int Health 2012; 17:1127-32. [PMID: 22809002 DOI: 10.1111/j.1365-3156.2012.03042.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To enable the human African trypanosomiasis (HAT) control program of the Democratic Republic of the Congo to generate data on treatment outcomes, an electronic database was developed. The database was piloted in two provinces, Bandundu and Kasai Oriental. In this study, we analysed routine data from the two provinces for the period 2006-2008. METHODS Data were extracted from case declaration cards and monthly reports available at national and provincial HAT coordination units and entered into the database. RESULTS Data were retrieved for 15 086 of 15 741 cases reported in the two provinces for the period (96%). Compliance with post-treatment follow-up was very poor in both provinces; only 25% had undergone at least one post-treatment follow-up examination, <1% had undergone the required four follow-up examinations. Relapse rates among those presenting for follow-up were high in Kasai (18%) but low in Bandundu (0.3%). CONCLUSIONS High relapse rates in Kasai and poor compliance with post-treatment follow-up in both provinces are important problems that the HAT control program urgently needs to address. Moreover, in analogy to tuberculosis control programs, HAT control programs need to adopt a recording and reporting routine that includes reporting on treatment outcomes.
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Affiliation(s)
- E Hasker
- Epidemiology and Disease Control Unit, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium.
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Hasker E, Lutumba P, Mumba D, Lejon V, Büscher P, Kande V, Muyembe JJ, Menten J, Robays J, Boelaert M. Diagnostic accuracy and feasibility of serological tests on filter paper samples for outbreak detection of T.b. gambiense human African trypanosomiasis. Am J Trop Med Hyg 2010; 83:374-9. [PMID: 20682885 DOI: 10.4269/ajtmh.2010.09-0735] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Control of human African trypanosomiasis (HAT) in the Democratic Republic of Congo is based on mass population screening by mobile teams; a costly and labor-intensive approach. We hypothesized that blood samples collected on filter paper by village health workers and processed in a central laboratory might be a cost-effective alternative. We estimated sensitivity and specificity of micro-card agglutination test for trypanosomiasis (micro-CATT) and enzyme-linked immunosorbent assay (ELISA)/T.b. gambiense on filter paper samples compared with parasitology-based case classification and used the results in a Monte Carlo simulation of a lot quality assurance sampling (LQAS) approach. Micro-CATT and ELISA/T.b. gambiense showed acceptable sensitivity (92.7% [95% CI 87.4-98.0%] and 82.2% [95% CI 75.3-90.4%]) and very high specificity (99.4% [95% CI 99.0-99.9%] and 99.8% [95% CI 99.5-100%]), respectively. Conditional on high sample size per lot (> or = 60%), both tests could reliably distinguish a 2% from a zero prevalence at village level. Alternatively, these tests could be used to identify individual HAT suspects for subsequent confirmation.
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Affiliation(s)
- Epco Hasker
- Institute of Tropical Medicine Antwerp, Belgium.
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Yun O, Priotto G, Tong J, Flevaud L, Chappuis F. NECT is next: implementing the new drug combination therapy for Trypanosoma brucei gambiense sleeping sickness. PLoS Negl Trop Dis 2010; 4:e720. [PMID: 20520803 PMCID: PMC2876135 DOI: 10.1371/journal.pntd.0000720] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Oliver Yun
- Médecins Sans Frontières/Doctors Without Borders, New York, New York, USA.
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Camara M, Camara O, Ilboudo H, Sakande H, Kaboré J, N'Dri L, Jamonneau V, Bucheton B. Sleeping sickness diagnosis: use of buffy coats improves the sensitivity of the mini anion exchange centrifugation test. Trop Med Int Health 2010; 15:796-9. [PMID: 20497407 DOI: 10.1111/j.1365-3156.2010.02546.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To evaluate a modification of the mini anion exchange centrifugation test (mAECT) for the diagnosis of Trypanosoma brucei (T.b.) gambiense human African trypanosomiasis (HAT). To increase its sensitivity, this test uses 350 microl of buffy coat withdrawn from 5 ml of blood instead of blood. METHODS The new protocol was first tested experimentally on serial dilution of trypanosomes and was then further evaluated under field conditions on 57 patients with HAT diagnosed during a medical survey in Guinea. RESULTS Experimentally, the use of buffy coats improved mAECT sensitivity at least five fold and enabled to consistently detect parasites in blood at a concentration of 10 trypanosomes/ml. During the field evaluation, more patients tested positive by mAECT-bc (96.5%) than by mAECT-blood (78.9%, chi(2) = 6.93, P = 0.008) and lymph juice examination (77.2%, chi(2) = 7.67, P = 0.005). Furthermore, the number of parasites per collectors was significantly higher (7.2 vs. 2.6, P = 0.001) when buffy coats were used instead of blood. CONCLUSION The use of the mAECT-bc protocol enabled a significant improvement of HAT parasitological diagnosis in Guinea, without any additional costs. It would deserve to be tested in other T.b. gambiense endemic areas.
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Affiliation(s)
- Mamadou Camara
- Programme National de Lutte contre la Trypanosomose Humaine Africaine, Conakry, Guinée
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14
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Hasker E, Mitashi P, Baelmans R, Lutumba P, Jacquet D, Lejon V, Kande V, Declercq J, Van der Veken W, Boelaert M. A new format of the CATT test for the detection of Human African Trypanosomiasis, designed for use in peripheral health facilities. Trop Med Int Health 2010; 15:263-7. [DOI: 10.1111/j.1365-3156.2009.02446.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Abstract
Human African trypanosomiasis (sleeping sickness) occurs in sub-Saharan Africa. It is caused by the protozoan parasite Trypanosoma brucei, transmitted by tsetse flies. Almost all cases are due to Trypanosoma brucei gambiense, which is indigenous to west and central Africa. Prevalence is strongly dependent on control measures, which are often neglected during periods of political instability, thus leading to resurgence. With fewer than 12 000 cases of this disabling and fatal disease reported per year, trypanosomiasis belongs to the most neglected tropical diseases. The clinical presentation is complex, and diagnosis and treatment difficult. The available drugs are old, complicated to administer, and can cause severe adverse reactions. New diagnostic methods and safe and effective drugs are urgently needed. Vector control, to reduce the number of flies in existing foci, needs to be organised on a pan-African basis. WHO has stated that if national control programmes, international organisations, research institutes, and philanthropic partners engage in concerted action, elimination of this disease might even be possible.
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Affiliation(s)
- Reto Brun
- Swiss Tropical Institute, Basel, Switzerland.
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16
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Vanhecke C, Guevart E, Ezzedine K, Receveur MC, Jamonneau V, Bucheton B, Camara M, Vincendeau P, Malvy D. [Human African trypanosomiasis in mangrove epidemiologic area. Presentation, diagnosis and treatment in Guinea, 2005-2007]. ACTA ACUST UNITED AC 2009; 58:110-6. [PMID: 19854583 DOI: 10.1016/j.patbio.2009.07.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2009] [Accepted: 07/19/2009] [Indexed: 11/30/2022]
Abstract
UNLABELLED Gambiense human African trypanosomiasis is still assumed to be endemic in many part of West Africa, particularly in Guinea coastal area with mangrove swamp. Diagnosis is usually made during active medical screening or by passive initiative. OBJECTIVES To describe clinical and epidemiological characteristics of Gambiense human African trypanosomiasis in the coastal area of Guinea. METHODS Exhaustive and retrospective analysis of all patients attending the trypanosomiasis center in the coastal area of Guinea between January 2005 and December 2007 with a diagnosis of human African trypanosomiasis. RESULTS A total of 196 patients were recruited for the study. Out of them, 55 % of the 73 patients diagnosed during active screening were classified stage 1 (haemolymphatic stage) or early stage 2 (meningoencephalitic stage). Contrarily, 115 of the 120 diagnosed by passive procedure were classified late stage 2, which features more specific signs and neurological symptoms, and leads to coma and death. More than 90 % of all cases presented cervical lymph nodes with identification of trypanosome on direct examination of fluid puncture. Less than one third of the patients were reexamined three months later. DISCUSSION In the coastal area of Guinea with mangrove swamp, direct examination of lymph node fluid puncture seems to be the most contributive test for the diagnosis of human African trypanosomiasis. Hence, associating clinical examination of cervical lymph nodes area and direct examination of fluid puncture may allow an early diagnosis of Gambiense human African trypanosomiasis and favor the implementation of efficient therapeutic strategies.
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Affiliation(s)
- C Vanhecke
- Centre Médicosocial, Ambassade de France, BP 351, Conakry, Guinée.
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Lutumba P, Meheus F, Robays J, Miaka C, Kande V, Büscher P, Dujardin B, Boelaert M. Cost-effectiveness of algorithms for confirmation test of human African trypanosomiasis. Emerg Infect Dis 2008; 13:1484-90. [PMID: 18257991 PMCID: PMC2851529 DOI: 10.3201/eid1310.060358] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Algorithms that incorporate concentration techniques are more effective and efficient than the currently used algorithms. The control of Trypanosoma brucei gambiense human African trypanosomiasis (HAT) is compromised by low sensitivity of the routinely used parasitologic confirmation tests. More sensitive alternatives, such as mini-anion exchange centrifugation technique (mAECT) or capillary tube centrifugation (CTC), are more expensive. We used formal decision analysis to assess the cost-effectiveness of alternative HAT confirmation algorithms in terms of cost per life saved. The effectiveness of the standard method, a combination of lymph node puncture (LNP), fresh blood examination (FBE), and thick blood film (TBF), was 36.8%; the LNP-FBE-CTC-mAECT sequence reached almost 80%. The cost per person examined ranged from €1.56 for LNP-FBE-TBF to €2.99 for LNP-TBF-CTC-mAECT-CATT (card agglutination test for trypanosomiasis) titration. LNP-TBF-CTC-mAECT was the most cost-effective in terms of cost per life saved. HAT confirmation algorithms that incorporate concentration techniques are more effective and efficient than the algorithms that are currently and routinely used by several T.b. gambiense control programs.
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Affiliation(s)
- Pascal Lutumba
- Programmed National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, Democratic Republic of Congo
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Lutumba P, Makieya E, Shaw A, Meheus F, Boelaert M. Human African trypanosomiasis in a rural community, Democratic Republic of Congo. Emerg Infect Dis 2007; 13:248-54. [PMID: 17479887 PMCID: PMC2725878 DOI: 10.3201/eid1302.060075] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
According to the World Health Organization, human African trypanosomiasis (HAT) (sleeping sickness) caused the loss of approximately 1.5 million disability-adjusted life years (DALYs) in 2002. We describe the effect of HAT during 2000-2002 in Buma, a rural community near Kinshasa in the Democratic Republic of Congo. We used retrospective questionnaire surveys to estimate HAT-related household costs and DALYs. The HAT outbreak in Buma involved 57 patients and affected 47 (21%) households. The cost to each household was equivalent to 5 months' income for that household. The total number of HAT-related DALYs was 2,145, and interventions to control HAT averted 1,408 DALYs. The cost per DALY averted was US $17. Because HAT has a serious economic effect on households and control interventions are cost-effective, considering only global burden of disease rankings for resource allocation could lead to misguided priority setting if applied without caution in HAT-affected countries.
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Affiliation(s)
- Pascal Lutumba
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, Democratic Republic of Congo
- Institute of Tropical Medicine, Antwerp, Belgium
| | - Eric Makieya
- University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | | | - Filip Meheus
- Royal Tropical Institute, Amsterdam, the Netherlands
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Inojosa WO, Augusto I, Bisoffi Z, Josenado T, Abel PM, Stich A, Whitty CJM. Diagnosing human African trypanosomiasis in Angola using a card agglutination test: observational study of active and passive case finding strategies. BMJ 2006; 332:1479. [PMID: 16777858 PMCID: PMC1482336 DOI: 10.1136/bmj.38859.531354.7c] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To assess the operational feasibility of detecting human African trypanosomiasis by active and passive case finding using the card agglutination test with serial dilution of serum to guide treatment. SETTING Trypanosomiasis control programme in the Negage focus, northern Angola, during a period of civil war. DESIGN Observational study. PARTICIPANTS 359 patients presenting themselves to health centres with symptoms (passive case finding) and 14,446 people actively screened in villages. MAIN OUTCOME MEASURES Whole blood and serological tests at different dilutions using the card agglutination test, and detection of parasites by microscopy. RESULTS Active case finding identified 251 people with a positive card agglutination test result, 10 of whom had confirmed parasites. In those presenting for investigation 34 of 51 with a positive card agglutination test result at the dilution of 1:8 or more used to guide treatment had parasites in blood, lymph node fluid, or cerebrospinal fluid, compared with 10 of 76 in those detected by active case finding: positive predictive values of 67% for passive case detection and 13% for active case detection. Only at a cut-off dilution more than 1:32 was the positive predictive value in active case detection reasonable (46%) and at this dilution 40% of microscopically proved cases were missed. CONCLUSIONS The card agglutination test is useful for initial screening in active detection of cases with human African trypanosomiasis but, given the toxicity of the drugs, serology using the card agglutination test should be not used alone to guide treatment after active case finding. A second confirmatory test is needed.
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Lutumba P, Robays J, Miaka C, Kande V, Mumba D, Büscher P, Dujardin B, Boelaert M. Validité, coût et faisabilité de la mAECT et CTC comme tests de confirmation dans la détection de la Trypanosomiase Humaine Africaine. Trop Med Int Health 2006; 11:470-8. [PMID: 16553930 DOI: 10.1111/j.1365-3156.2006.01591.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To evaluate the validity, cost and feasibility of two parasitological tests for the confirmation of Human African Trypanosomiasis (HAT): the mini Anion-exchange Centrifugation Technique (mAECT) and Capillary Tube Centrifugation (CTC). METHODS During a sleeping sickness screening campaign in 2004 we screened 6502 people in Kwamouth, DRC. Those with a positive result in the Card Agglutination Test for Trypanosomiasis (CATT) had a gland puncture, fresh blood examination, stained thick blood film, mAECT, CTC and CATT titration. Sensitivity and specificity of the confirmation tests were calculated using the combination of all parasitological tests as a reference standard. Each method was costed and its feasibility was assessed with structured interviews of the technicians. RESULTS Sensitivity of classical parasitological methods was 44.8% (36.8-53.0), of CTC 56.5% (48.3-64.5) and of mAECT 75.3% (95% CI: 67.7-81.9). Cost per test was 2.82 Euro for mAECT and 0.76 Euro for CTC. Time per test was 29.78 min for mAECT and 18.25 min for CTC. These two tests were judged feasible in field conditions. CONCLUSION CTC and mAECT used alone or in combination would bring a considerable improvement to HAT active case finding when used as confirmation tests in CATT-whole blood-positive persons. They proved feasible in operational conditions if a 220 V power supply can be guaranteed. As mAECT is more sensitive but also considerably more expensive, efficiency as well as feasibility considerations will have to guide the choice of the best algorithm.
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Affiliation(s)
- P Lutumba
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, République Démocratique du Congo
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