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Yalley AK, Ahiatrogah S, Kafintu-Kwashie AA, Amegatcher G, Prah D, Botwe AK, Adusei-Poku MA, Obodai E, Nii-Trebi NI. A Systematic Review on Suitability of Molecular Techniques for Diagnosis and Research into Infectious Diseases of Concern in Resource-Limited Settings. Curr Issues Mol Biol 2022; 44:4367-4385. [PMID: 36286015 PMCID: PMC9601131 DOI: 10.3390/cimb44100300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/15/2022] [Accepted: 09/16/2022] [Indexed: 11/16/2022] Open
Abstract
Infectious diseases significantly impact the health status of developing countries. Historically, infectious diseases of the tropics especially have received insufficient attention in worldwide public health initiatives, resulting in poor preventive and treatment options. Many molecular tests for human infections have been established since the 1980s, when polymerase chain reaction (PCR) testing was introduced. In spite of the substantial innovative advancements in PCR technology, which currently has found wide application in most viral pathogens of global concern, the development and application of molecular diagnostics, particularly in resource-limited settings, poses potential constraints. This review accessed data from sources including PubMed, Google Scholar, the Web of Knowledge, as well as reports from the World Health Organization’s Annual Meeting on infectious diseases and examined these for current molecular approaches used to identify, monitor, or investigate some neglected tropical infectious diseases. This review noted some growth efforts in the development of molecular techniques for diagnosis of pathogens that appear to be common in resource limited settings and identified gaps in the availability and applicability of most of these molecular diagnostics, which need to be addressed if the One Health goal is to be achieved.
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Affiliation(s)
- Akua K. Yalley
- Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, University of Ghana, Accra P.O. Box KB 143, Ghana
| | - Selasie Ahiatrogah
- Department of Obstetrics and Gynaecology, College of Medicine, Pan African University of Life and Earth Sciences Institute, University of Ibadan, Ibadan P.O. Box 22133, Nigeria
| | - Anna A. Kafintu-Kwashie
- Department of Medical Microbiology, University of Ghana Medical School, Accra GA-221-1570, Ghana
| | - Gloria Amegatcher
- Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, University of Ghana, Accra P.O. Box KB 143, Ghana
| | - Diana Prah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra P.O. Box LG 54, Ghana
| | - Akua K. Botwe
- Molecular Biology Unit, Kintampo Health Research Centre, Ghana Health Service, Kintampo P.O. Box 200, Ghana
| | - Mildred A. Adusei-Poku
- Department of Medical Microbiology, University of Ghana Medical School, Accra GA-221-1570, Ghana
| | - Evangeline Obodai
- Department of Virology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra P.O. Box LG 581, Ghana
| | - Nicholas I. Nii-Trebi
- Department of Medical Laboratory Sciences, School of Biomedical and Allied Health Sciences, University of Ghana, Accra P.O. Box KB 143, Ghana
- Correspondence: ; Tel.: +233-54-827-6424
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A novel metabarcoded deep amplicon sequencing tool for disease surveillance and determining the species composition of Trypanosoma in cattle and other farm animals. Acta Trop 2022; 230:106416. [PMID: 35317999 DOI: 10.1016/j.actatropica.2022.106416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 11/21/2022]
Abstract
The World Health Organization (WHO) and the Food and Agriculture Organization (FAO) have developed strategies to control trypanosomiasis in humans and livestock in endemic areas. These require a better understanding of the distribution of different Trypanosoma species and improved predictions of where they might appear in the future, based on accurate diagnosis and robust surveillance systems. Here, we describe a metabarcoding deep amplicon sequencing method to identify and determine the Trypanosoma species in co-infecting communities. First, four morphological verified Trypanosoma species (T. brucei, T. congolense, T. vivax and T. theileri) were used to prepare test DNA pools derived from different numbers of parasites to evaluate the method's detection threshold for each of the four species and to assess the accuracy of their proportional quantification. Having demonstrated the accurate determination of species composition in Trypanosoma communities, the method was applied to determine its detection threshold using blood samples collected from cattle with confirmed Trypanosoma infections based on a PCR assay. Each sample showed a different Trypanosoma species composition based on the proportion of MiSeq reads. Finally, we applied the assay to field samples to develop new insight into the species composition of Trypanosoma communities in cattle, camels, buffalo, horses, sheep, and goat in endemically infected regions of Pakistan. We confirmed that Trypanosoma evansi is the major species in Pakistan and for the first time showed the presence of Trypanosoma theileri. The metabarcoding deep amplicon sequencing method and bioinformatics pathway have several potential applications in animal and human research, including evaluation of drug treatment responses, understanding of the emergence and spread of drug resistance, and description of species interactions during co-infections and determination of host and geographic distribution of trypanosomiasis in humans and livestock.
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Kaiser N, Mejuch T, Fedoryshchak R, Janning P, Tate EW, Waldmann H. Photoactivatable Myristic Acid Probes for UNC119-Cargo Interactions. Chembiochem 2018; 20:134-139. [DOI: 10.1002/cbic.201800406] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Indexed: 01/01/2023]
Affiliation(s)
- Nadine Kaiser
- Department of Chemical Biology; Max-Planck-Institute of, Molecular Physiology; Otto-Hahn-Strasse 11 44227 Dortmund Germany
- Faculty of Chemistry and Chemical Biology; TU Dortmund University; Otto-Hahn-Strasse 6 44227 Dortmund Germany
| | - Tom Mejuch
- Department of Chemical Biology; Max-Planck-Institute of, Molecular Physiology; Otto-Hahn-Strasse 11 44227 Dortmund Germany
- Faculty of Chemistry and Chemical Biology; TU Dortmund University; Otto-Hahn-Strasse 6 44227 Dortmund Germany
| | - Roman Fedoryshchak
- Department of Chemistry; Imperial College London; Exhibition Road London SW7 2AZ UK
| | - Petra Janning
- Department of Chemical Biology; Max-Planck-Institute of, Molecular Physiology; Otto-Hahn-Strasse 11 44227 Dortmund Germany
| | - Edward W. Tate
- Department of Chemistry; Imperial College London; Exhibition Road London SW7 2AZ UK
| | - Herbert Waldmann
- Department of Chemical Biology; Max-Planck-Institute of, Molecular Physiology; Otto-Hahn-Strasse 11 44227 Dortmund Germany
- Faculty of Chemistry and Chemical Biology; TU Dortmund University; Otto-Hahn-Strasse 6 44227 Dortmund Germany
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Jamonneau V, Garcia A, Frezil JL, N'Guessan P, N'Dri L, Sanon R, Laveissière C, Truc P. Clinical and biological evolution of human trypanosomiasis in Côte d'Ivoire. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.2000.11813607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Pritt BS. Molecular Diagnostics in the Diagnosis of Parasitic Infection. METHODS IN MICROBIOLOGY 2015. [DOI: 10.1016/bs.mim.2015.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Human African trypanosomiasis with 7-year incubation period: clinical, laboratory and neuroimaging findings. Parasitol Int 2014; 63:557-60. [PMID: 24613272 DOI: 10.1016/j.parint.2014.02.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 01/31/2014] [Accepted: 02/15/2014] [Indexed: 11/20/2022]
Abstract
Human African trypanosomiasis (HAT), also referred to as "sleeping sickness", is caused by the parasite Trypanosoma brucei. Diagnosing imported HAT outside endemic areas is difficult and diagnosis is often delayed. We report a case of imported human African trypanosomiasis caused by Trypanosoma brucei gambiense with an unusually long incubation period of at least 7 years. A 33 year old male African patient, a former resident of Cameroon, presented with a 4-month history of progressive personality changes. A few weeks before presentation the patient had first been admitted to a psychiatric ward and received antidepressant treatment, until a lumbar puncture showed pleocytosis and then antibiotic treatment for suspected neuroborreliosis was initiated. The patient continued to deteriorate during antibiotic treatment and became increasingly lethargic. Under antiparasitic and anti-inflammatory treatment, the condition of the patient gradually improved over the following months and he recovered completely after 24 months of follow-up. This well-documented case illustrates typical difficulties in establishing the correct diagnosis outside endemic areas and provides an overview of typical clinical, neuropathological and neuroimaging findings in T. b. gambiense trypanosomiasis, guiding the clinician in establishing the correct diagnosis in this rare disease.
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Mugasa CM, Katiti D, Boobo A, Lubega GW, Schallig HD, Matovu E. Comparison of nucleic acid sequence-based amplification and loop-mediated isothermal amplification for diagnosis of human African trypanosomiasis. Diagn Microbiol Infect Dis 2014; 78:144-8. [DOI: 10.1016/j.diagmicrobio.2013.06.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 06/24/2013] [Accepted: 06/25/2013] [Indexed: 11/28/2022]
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Holzmuller P, Grébaut P, Semballa S, Gonzatti MI, Geiger A. Proteomics: a new way to improve human African trypanosomiasis diagnosis? Expert Rev Proteomics 2014; 10:289-301. [DOI: 10.1586/epr.13.14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Deborggraeve S, Büscher P. Recent progress in molecular diagnosis of sleeping sickness. Expert Rev Mol Diagn 2014; 12:719-30. [DOI: 10.1586/erm.12.72] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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PCR based diagnosis of trypanosomiasis exploring invariant surface glycoprotein (ISG) 75 gene. Vet Parasitol 2012; 193:47-58. [PMID: 23305969 DOI: 10.1016/j.vetpar.2012.11.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 11/29/2012] [Accepted: 11/30/2012] [Indexed: 11/20/2022]
Abstract
The invariant surface glycoprotein (ISG-75) gene of Trypanosoma evansi buffalo isolate from Karnataka state in India was sequenced and analyzed to elucidate its relationship with other isolates/species. The sequenced ISG-75 gene was also explored to device a polymerase chain reaction (PCR) strategy for the diagnosis of trypanosomiasis in carrier animals. The six cloned ISG gene sequences revealed the open reading frame (ORF) of 1572 and 1527 nucleotide (nt) encoding a polypeptide of 523 and 508 amino acids (aa) respectively and belongs ISG-75 gene family. Sequence analysis revealed 91-100% and 65-99% similarity at nt and aa levels, respectively with other isolates/species and belongs to the RoTat 1.2 strain. The diagnostic PCR based on ISG-75 sequence amplifies a 407 bp product specifically from the different T. evansi isolates and could detect 0.04 pg and 1.2 ng of DNA from purified trypanosomes and T. evansi infected rat blood samples respectively. Subsequently the PCR detected 0.02 and 0.27 trypanosomes ml(-1) respectively, from purified trypanosomes and T. evansi (buffalo isolate) infected rat blood. By the developed PCR assay trypanosomal nucleic acid was detected in experimental rats and buffalo on 24 h post infection (p.i.) and 3rd day post infection (d.p.i.), respectively. The developed ISG-75 gene based PCR assay could be useful in detection of carrier status of trypanosomiasis in animals.
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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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Diagnostic accuracy of molecular amplification tests for human African trypanosomiasis--systematic review. PLoS Negl Trop Dis 2012; 6:e1438. [PMID: 22253934 PMCID: PMC3254661 DOI: 10.1371/journal.pntd.0001438] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 10/31/2011] [Indexed: 12/01/2022] Open
Abstract
Background A range of molecular amplification techniques have been developed for the diagnosis of Human African Trypanosomiasis (HAT); however, careful evaluation of these tests must precede implementation to ensure their high clinical accuracy. Here, we investigated the diagnostic accuracy of molecular amplification tests for HAT, the quality of articles and reasons for variation in accuracy. Methodology Data from studies assessing diagnostic molecular amplification tests were extracted and pooled to calculate accuracy. Articles were included if they reported sensitivity and specificity or data whereby values could be calculated. Study quality was assessed using QUADAS and selected studies were analysed using the bivariate random effects model. Results 16 articles evaluating molecular amplification tests fulfilled the inclusion criteria: PCR (n = 12), NASBA (n = 2), LAMP (n = 1) and a study comparing PCR and NASBA (n = 1). Fourteen articles, including 19 different studies were included in the meta-analysis. Summary sensitivity for PCR on blood was 99.0% (95% CI 92.8 to 99.9) and the specificity was 97.7% (95% CI 93.0 to 99.3). Differences in study design and readout method did not significantly change estimates although use of satellite DNA as a target significantly lowers specificity. Sensitivity and specificity of PCR on CSF for staging varied from 87.6% to 100%, and 55.6% to 82.9% respectively. Conclusion Here, PCR seems to have sufficient accuracy to replace microscopy where facilities allow, although this conclusion is based on multiple reference standards and a patient population that was not always representative. Future studies should, therefore, include patients for which PCR may become the test of choice and consider well designed diagnostic accuracy studies to provide extra evidence on the value of PCR in practice. Another use of PCR for control of disease could be to screen samples collected from rural areas and test in reference laboratories, to spot epidemics quickly and direct resources appropriately. A range of molecular amplification techniques has been developed for the diagnosis of HAT, with polymerase chain reaction (PCR) at the forefront. As laboratory strengthening in endemic areas increases, it is expected that the applicability of molecular tests will increase. However, careful evaluation of these tests against the current reference standard, microscopy, must precede implementation. Therefore, we have investigated the published diagnostic accuracy of molecular amplification tests for HAT compared to microscopy for both initial diagnosis as well as for disease staging. Here, PCR tests seem to have an acceptably high specificity and sensitivity for diagnosis of stage I HAT. This conclusion is, however, based on multiple-microscopy based techniques as reference standards, which may have low sensitivity, and a patient population that was not always representative. Future studies should, therefore, first and foremost include those patients for which PCR may become the test of choice. More certainty about the practical value of PCR tests for HAT diagnosis should come from non-accuracy design studies, like feasibility or cost-effectiveness studies.
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Bucheton B, MacLeod A, Jamonneau V. Human host determinants influencing the outcome of Trypanosoma brucei gambiense infections. Parasite Immunol 2011; 33:438-47. [PMID: 21385185 PMCID: PMC3427891 DOI: 10.1111/j.1365-3024.2011.01287.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Since first identified, human African trypanosomiasis (HAT) or sleeping sickness has been described as invariably fatal. Increasing data however argue that infection by Trypanosoma brucei gambiense, the causative agent of HAT, results in a wide range of outcomes in its human host and importantly that a number of subjects in endemic areas are apparently able to control infection to low levels, undetectable by the classical parasitological tests used in the field. Thus, trypanotolerance seems to occur in humans as has already been described in cattle or in the rodent experimental models of infection. This review focuses on the description of the diversity of outcomes resulting from T. b. gambiense in humans and on the host factors involved. The consequences/impacts on HAT epidemiology resulting from this diversity are also discussed with regard to implementing sustainable HAT control strategies.
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Affiliation(s)
- B Bucheton
- Institut de Recherche pour le Développement (IRD), Unité Mixte de Recherche IRD-CIRAD 177, Campus International de Baillarguet, Montpellier, France.
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Checchi F, Chappuis F, Karunakara U, Priotto G, Chandramohan D. Accuracy of five algorithms to diagnose gambiense human African trypanosomiasis. PLoS Negl Trop Dis 2011; 5:e1233. [PMID: 21750745 PMCID: PMC3130008 DOI: 10.1371/journal.pntd.0001233] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/23/2011] [Indexed: 11/24/2022] Open
Abstract
Background Algorithms to diagnose gambiense human African trypanosomiasis (HAT, sleeping sickness) are often complex due to the unsatisfactory sensitivity and/or specificity of available tests, and typically include a screening (serological), confirmation (parasitological) and staging component. There is insufficient evidence on the relative accuracy of these algorithms. This paper presents estimates of the accuracy of five algorithms used by past Médecins Sans Frontières programmes in the Republic of Congo, Southern Sudan and Uganda. Methodology and Principal Findings The sequence of tests in each algorithm was programmed into a probabilistic model, informed by distributions of the sensitivity, specificity and staging accuracy of each test, constructed based on a literature review. The accuracy of algorithms was estimated in a baseline scenario and in a worst-case scenario introducing various near worst-case assumptions. In the baseline scenario, sensitivity was estimated as 85–90% in all but one algorithm, with specificity above 99.9% except for the Republic of Congo, where CATT serology was used as independent confirmation test: here, positive predictive value (PPV) was estimated at <50% in realistic active screening prevalence scenarios. Furthermore, most algorithms misclassified about one third of true stage 1 cases as stage 2, and about 10% of true stage 2 cases as stage 1. In the worst-case scenario, sensitivity was 75–90% and PPV no more than 75% at 1% prevalence, with about half of stage 1 cases misclassified as stage 2. Conclusions Published evidence on the accuracy of widely used tests is scanty. Algorithms should carefully weigh the use of serology alone for confirmation, and could enhance sensitivity through serological suspect follow-up and repeat parasitology. Better evidence on the frequency of low-parasitaemia infections is needed. Simulation studies should guide the tailoring of algorithms to specific scenarios of HAT prevalence and availability of control tools. Gambiense human African trypanosomiasis (HAT, sleeping sickness) usually features low prevalence. The two stages of the disease require different treatments, and stage 2 is fatal if untreated. HAT diagnosis must therefore be highly sensitive (i.e., detect as many true cases as possible) and specific (i.e., minimize false positives). HAT diagnostic algorithms are complex and involve several tests to screen for, confirm and stage infection. We analyzed five algorithms used by Médecins Sans Frontières HAT programmes. We combined published data on the accuracy of each test in the algorithm with a computer program that simulates all possible algorithm branches. We found that all algorithms had reasonable sensitivity (85–90%); specificity was high (>99.9%) except for the Republic of Congo, where confirmation did not rely on microscopic evidence, resulting in frequent false positives (but also higher sensitivity). Algorithms misclassified about one third of stage 1 cases as stage 2, but stage 2 classification was highly accurate. The use of serology alone for confirmation merits caution. HAT diagnosis could be made more sensitively by following up serological suspects and repeating microscopic examinations. Computer simulations can help to adapt algorithms to local conditions in each HAT programme, such as the prevalence of infection and operational constraints.
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Ilboudo H, Jamonneau V, Camara M, Camara O, Dama E, Léno M, Ouendeno F, Courtin F, Sakande H, Sanon R, Kaboré J, Coulibaly B, N'Dri L, Diarra A, N'Goran E, Bucheton B. Diversity of response to Trypanosoma brucei gambiense infections in the Forecariah mangrove focus (Guinea): perspectives for a better control of sleeping sickness. Microbes Infect 2011; 13:943-52. [PMID: 21658462 DOI: 10.1016/j.micinf.2011.05.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 05/11/2011] [Accepted: 05/13/2011] [Indexed: 11/29/2022]
Abstract
At a time when human African trypanosomiasis (HAT) elimination again seems a reachable goal in many parts of sub-Saharan Africa, it is becoming increasingly important to characterise the factors involved in disease resurgence or maintenance to develop sustainable control strategies. In this study conducted in the Forecariah mangrove focus in Guinea, HAT patients and serological suspects (SERO) were identified through mass screening of the population with the Card Agglutination Test for Trypanosomiasis (CATT) and were followed up for up to 2 years. Analysis of the samples collected during the follow-up of HAT patients and SERO was performed with PCR (TBR1/TBR2) and the trypanolysis serological test (TL) in order to clarify the role played by these individuals in the epidemiology of HAT. PCR positivity was higher in TL⁺ than in SERO TL⁻ (50% vs. 18%, respectively). Whereas CATT plasma titres decreased both in treated HAT patients and SERO TL⁻, SERO TL⁺ maintained high CATT titres. Four out of 17 SERO TL⁺ developed HAT during the study. These results strongly suggest that SERO TL⁺ individuals are asymptomatic carriers. In the context where disease prevalence is sufficiently low, treating SERO TL⁺ individual may thus be of crucial importance in order to cut transmission.
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Affiliation(s)
- Hamidou Ilboudo
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), 01BP454 Bobo-Dioulasso 01, Burkina Faso
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First evidence that parasite infecting apparent aparasitemic serological suspects in human African trypanosomiasis are Trypanosoma brucei gambiense and are similar to those found in patients. INFECTION GENETICS AND EVOLUTION 2011; 11:1250-5. [PMID: 21530681 DOI: 10.1016/j.meegid.2011.04.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 04/07/2011] [Accepted: 04/11/2011] [Indexed: 11/20/2022]
Abstract
Thanks to its sensitivity and its ease of use in the field, the card agglutination test for trypanosomiasis (CATT) is widely used for serological screening of Trypanosoma brucei gambiense human African trypanosomiasis (HAT). Positive subjects are then examined by microscopy to confirm the disease. However, the CATT exhibits false-positive results raising the question of whether CATT-positive subjects who are not confirmed by microscopic detection of trypanosomes (SERO) are truly exposed to T.b. gambiense infection. For this purpose, we applied microsatellite genotyping on DNA extracted from blood of both HAT confirmed patients and SERO subjects in Guinea and Côte d'Ivoire since microsatellite genotyping has proved useful for the study of T.b. gambiense genetic diversity. Problems of amplification failures raise the question of the sensitivity of microsatellite markers when applied on biological samples especially from SERO subjects for who low blood parasitaemia are suspected. Nevertheless, we have shown that the trypanosomes from SERO individuals that have been genotyped belong to T.b. gambiense group 1 and were identical to those found in HAT patients. These results constitute the first evidences that at least some SERO are indeed infected by T.b. gambiense group 1 and that they may constitute a human reservoir of parasite in HAT foci. Whether these individuals should undergo treatment remains an open question as long as their role in HAT transmission is unknown. Our results strongly recommend the follow-up of such subjects to improve control strategies.
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Sengupta P, Balumahendiran M, Suryanaryana V, Raghavendra A, Shome B, Gajendragad M, Prabhudas K. PCR-based diagnosis of surra-targeting VSG gene: Experimental studies in small laboratory rodents and buffalo. Vet Parasitol 2010; 171:22-31. [DOI: 10.1016/j.vetpar.2010.03.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Revised: 02/16/2010] [Accepted: 03/11/2010] [Indexed: 10/19/2022]
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Deborggraeve S, Büscher P. Molecular diagnostics for sleeping sickness: what is the benefit for the patient? THE LANCET. INFECTIOUS DISEASES 2010; 10:433-9. [DOI: 10.1016/s1473-3099(10)70077-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
SUMMARYHuman African trypanosomiasis (HAT) or sleeping sickness is caused by protozoan parasitesTrypanosoma brucei gambienseandT. b. rhodesiense. Despite the enormous technological progress in molecular parasitology in recent years, the diagnosis of HAT is still problematic due to the lack of specific tools. To date, there are two realities when it comes to HAT; the first one being the world of modern experimental laboratories, equipped with the latest state-of-the-art technology, and the second being the world of HAT diagnosis, where the latest semi-commercial test was introduced 30 years ago (Magnuset al.1978). Hence, it appears that the lack of progress in HAT diagnosis is not primarily due to a lack of scientific interest or a lack of research funds, but mainly results from the many obstacles encountered in the translation of basic research into field-applicable diagnostics. This review will provide an overview of current diagnostic methods and highlight specific difficulties in solving the shortcomings of these methods. Future perspectives for accurate, robust, affordable diagnostics will be discussed as well.
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Magez S, Radwanska M. African trypanosomiasis and antibodies: implications for vaccination, therapy and diagnosis. Future Microbiol 2010; 4:1075-87. [PMID: 19824795 DOI: 10.2217/fmb.09.65] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
African trypanosomiasis causes devastating effects on human populations and livestock herds in large parts of sub-Saharan Africa. Control of the disease is hampered by the lack of any efficient vaccination results in a field setting, and the severe side effects of current drug therapies. In addition, with the exception of Trypanosoma brucei gambiense infections, the diagnosis of trypanosomiasis has to rely on microscopic analysis of blood samples, as other specific tools are nonexistent. However, new developments in biotechnology, which include loop-mediated isothermal amplification as an adaptation to conventional PCR, as well as the antibody engineering that has allowed the development of Nanobody technology, offer new perspectives in both the detection and treatment of trypanosomiasis. In addition, recent data on parasite-induced B-cell memory destruction offer new insights into mechanisms of vaccine failure, and should lead us towards new strategies to overcome trypanosome defenses operating against the host immune system.
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Affiliation(s)
- Stefan Magez
- Department of Molecular & Cellular Interactions, Flanders Institute for Biotechnology, Rijvisschestraat 120, B-9052 Ghent, Belgium.
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Nucleic acid sequence-based amplification with oligochromatography for detection of Trypanosoma brucei in clinical samples. J Clin Microbiol 2008; 47:630-5. [PMID: 19116352 DOI: 10.1128/jcm.01430-08] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Molecular tools, such as real-time nucleic acid sequence-based amplification (NASBA) and PCR, have been developed to detect Trypanosoma brucei parasites in blood for the diagnosis of human African trypanosomiasis (HAT). Despite good sensitivity, these techniques are not implemented in HAT control programs due to the high cost of the equipment, which is unaffordable for laboratories in developing countries where HAT is endemic. In this study, a simplified technique, oligochromatography (OC), was developed for the detection of amplification products of T. brucei 18S rRNA by NASBA. The T. brucei NASBA-OC test has analytical sensitivities of 1 to 10 parasites/ml on nucleic acids extracted from parasite culture and 10 parasites/ml on spiked blood. The test showed no reaction with nontarget pathogens or with blood from healthy controls. Compared to the composite standard applied in the present study, i.e., parasitological confirmation of a HAT case by direct microscopy or by microscopy after concentration of parasites using either a microhematocrit centrifugation technique or a mini-anion-exchange centrifugation technique, NASBA-OC on blood samples had a sensitivity of 73.0% (95% confidence interval, 60 to 83%), while standard expert microscopy had a sensitivity of 57.1% (95% confidence interval, 44 to 69%). On cerebrospinal fluid samples, NASBA-OC had a sensitivity of 88.2% (95% confidence interval, 75 to 95%) and standard microscopy had a sensitivity of 86.2% (95% confidence interval, 64 to 88%). The T. brucei NASBA-OC test developed in this study can be employed in field laboratories, because it does not require a thermocycler; a simple heat block or a water bath maintained at two different temperatures is sufficient for amplification.
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23
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Fernández D, González-Baradat B, Eleizalde M, González-Marcano E, Perrone T, Mendoza M. Trypanosoma evansi: A comparison of PCR and parasitological diagnostic tests in experimentally infected mice. Exp Parasitol 2008; 121:1-7. [PMID: 18848544 DOI: 10.1016/j.exppara.2008.09.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 09/16/2008] [Accepted: 09/18/2008] [Indexed: 11/30/2022]
Abstract
Trypanosoma evansi is the causative agent of equine trypanosomosis, disease that affects horse's productivity and health. Parasitological and molecular methods are mostly used to detect the infection. The aim of this work was evaluate PCR sensitivity to detect T. evansi using the primers 21/22-mer, ITS1, ESAG 6/7 and TBR 1/2 designed from repetitive (multicopies) genomic sequences. The results were compare with two parasitological tests in mice, micro-haematocrite centrifugation technique and direct microscopic examination. The results shows (a) that the minimum amount of DNA from blood of highly parasitaemic mice that was detectable by PCR was 0.001 ng, using the ESAG6/7 and TBR1/2 primer, (b) using TBR1/2 primer for parasites purified could detect 0.000001 ng and (c) in the prepatent period PCR detect the presence of parasites earlier than parasitological techniques. Nevertheless, the percentage of detection for PCR varies depending on primer employed with 60% and 66% for ITS1 and 21/22-mer, and 80% for ESAG6/7 and TBR1/2. Consequently, TBR1/2 and ESAG6/7 were the best primers to monitor T. evansi infections in mice. For epidemiological application, such comparative evaluation should be made for detection of T. evansi in livestock such as horses.
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Affiliation(s)
- D Fernández
- Universidad Nacional Experimental Simón Rodríguez, Instituto de Estudios Científicos y Tecnológicos, Centro de Estudios Biomédicos y Veterinarios, Apartado Postal 47925, Caracas 1041A, Venezuela
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24
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Detection of Trypanosoma brucei parasites in blood samples using real-time nucleic acid sequence-based amplification. Diagn Microbiol Infect Dis 2008; 61:440-5. [PMID: 18486402 DOI: 10.1016/j.diagmicrobio.2008.03.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 03/18/2008] [Accepted: 03/28/2008] [Indexed: 11/23/2022]
Abstract
Currently, the conventional diagnosis of human African trypanosomiasis (HAT) is by microscopic demonstration of trypomastigotes in blood, lymph, and/or cerebrospinal fluid. However, microscopic diagnosis of HAT is not sensitive enough and may give false-negative results, thus, denying the patient the necessary treatment of the otherwise fatal disease. For this reason, a highly sensitive technique needs to be developed to enhance case findings. In this study, the real-time nucleic acid sequence-based amplification assay described is based on amplification and concurrent detection of small subunit rRNA (18S rRNA) of Trypanosoma brucei. The sensitivity of the assay was evaluated on nucleic acid from in vitro cultured parasites and blood spiked with various parasites quantities. The assay detected 10 parasites/mL using cultured parasites as well as spiked blood. A sensitive assay such as the one developed in this study may become an alternative tool to confirm diagnosis of human African trypanosomiasis.
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25
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Deborggraeve S, Claes F, Laurent T, Mertens P, Leclipteux T, Dujardin JC, Herdewijn P, Büscher P. Molecular dipstick test for diagnosis of sleeping sickness. J Clin Microbiol 2006; 44:2884-9. [PMID: 16891507 PMCID: PMC1594664 DOI: 10.1128/jcm.02594-05] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human African trypanosomiasis (HAT) or sleeping sickness is a neglected disease that affects poor rural populations across sub-Saharan Africa. Confirmation of diagnosis is based on detection of parasites in either blood or lymph by microscopy. Here we present the development and the first-phase evaluation of a simple and rapid test (HAT-PCR-OC [human African trypanosomiasis-PCR-oligochromatography]) for detection of amplified Trypanosoma brucei DNA. PCR products are visualized on a dipstick through hybridization with a gold-conjugated probe (oligochromatography). Visualization is straightforward and takes only 5 min. Controls both for the PCR and for DNA migration are incorporated into the assay. The lower detection limit of the test is 5 fg of pure T. brucei DNA. One parasite in 180 microl of blood is still detectable. Sensitivity and specificity for T. brucei were calculated at 100% when tested on blood samples from 26 confirmed sleeping sickness patients, 18 negative controls (nonendemic region), and 50 negative control blood samples from an endemic region. HAT-PCR-OC is a promising new tool for diagnosis of sleeping sickness in laboratory settings, and the diagnostic format described here may have wider application for other infectious diseases.
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Affiliation(s)
- S Deborggraeve
- Department of Parasitology, Institute of Tropical Medicine, Nationalestraat 155, B-2000 Antwerpen, Belgium.
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26
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Koffi M, Solano P, Denizot M, Courtin D, Garcia A, Lejon V, Büscher P, Cuny G, Jamonneau V. Aparasitemic serological suspects in Trypanosoma brucei gambiense human African trypanosomiasis: a potential human reservoir of parasites? Acta Trop 2006; 98:183-8. [PMID: 16723098 DOI: 10.1016/j.actatropica.2006.04.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Revised: 01/18/2006] [Accepted: 04/13/2006] [Indexed: 11/24/2022]
Abstract
The serological and parasitological tests used for Trypanosoma brucei gambiense human African trypanosomiasis (HAT) diagnosis have low specificity and sensitivity, respectively, and in the field, control program teams are faced with subjects with positive serology but negative parasitology who remain untreated. The aim of this work was to explore, using PCR tool, the significance of these aparasitemic serological suspects. Since discordant PCR results have been observed earlier with different extraction methods, two DNA extraction methods were compared (the Chelex 100 resin and the DNeasy Tissue kit). The study was conducted on 604 blood samples: 574 from parasitologically confirmed patients, aparasitemic serological suspects and endemic controls collected in Côte d'Ivoire and 30 from healthy volunteers collected in France. No significant differences were observed between the PCR results obtained with the two extraction methods. Concerning PCR, problems of reproducibility and discordances with both serological and parasitological test results were observed, mainly for the aparasitemic serological suspects. In addition to previous results that pointed to the existence of non-virulent or non-pathogenic trypanosome strains and of individual susceptibility leading to long term seropositivity without detectable parasitaemia but positive PCR, the results of this study support the notion of a long lasting human reservoir that may contribute to the maintenance or periodic resurgences of HAT in endemic foci.
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Affiliation(s)
- M Koffi
- Institut de Recherche Pour le Développement, Unité de Recherche 177, Programme Santé Animale, TA 207/G, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France
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27
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Fèvre EM, Picozzi K, Jannin J, Welburn SC, Maudlin I. Human African Trypanosomiasis: Epidemiology and Control. ADVANCES IN PARASITOLOGY 2006; 61:167-221. [PMID: 16735165 DOI: 10.1016/s0065-308x(05)61005-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Human African trypanosomiasis (HAT), or sleeping sickness, describes not one but two discrete diseases: that caused by Trypanosoma brucei rhodesiense and that caused by T. b. gambiense. The Gambian form is currently a major public health problem over vast areas of central and western Africa, while the zoonotic, Rhodesian form continues to present a serious health risk in eastern and southern Africa. The two parasites cause distinct clinical manifestations, and there are significant differences in the epidemiology of the diseases caused. We discuss the differences between the diseases caused by the two parasites, with an emphasis on disease burden, reservoir hosts, transmission, diagnosis, treatment and control. We analyse how these differences impacted on historical disease control trends and how they can inform contemporary treatment and control options. We consider the optimal ways in which to devise HAT control policies in light of the differing biology and epidemiology of the parasites, and emphasise, in particular, the wider aspects of control policy, outlining the responsibilities of individuals, governments and international organisations in control programmes.
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Affiliation(s)
- E M Fèvre
- Centre for Infectious Diseases, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian, EH25 9RG, UK
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28
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Cox A, Tilley A, McOdimba F, Fyfe J, Eisler M, Hide G, Welburn S. A PCR based assay for detection and differentiation of African trypanosome species in blood. Exp Parasitol 2005; 111:24-9. [PMID: 16054487 DOI: 10.1016/j.exppara.2005.03.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Revised: 03/11/2005] [Accepted: 03/13/2005] [Indexed: 11/18/2022]
Abstract
Direct PCR analysis of trypanosome infected blood samples in the quantities required for large scale epidemiological study has always been problematic. Current methods for identifying and differentiating trypanosomes typically require several species-specific reactions, many of which rely on mouse passaged samples to obtain quality concentrated genomic DNA. As a consequence important epidemiological information may be lost during the sample preparation stage. Here, we report a PCR methodology that reduces processing and improves on the sensitivity of present screening methods. The PCR technique targets the gene encoding the small ribosomal subunit in order to identify and differentiate all clinically important African trypanosome species and some subspecies. The method is more economical, simple, and sensitive than current screening methods, and yields more detailed information, thereby making it a viable tool for large-scale epidemiological studies.
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Affiliation(s)
- Andrew Cox
- Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, Scotland, UK
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29
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Chappuis F, Loutan L, Simarro P, Lejon V, Büscher P. Options for field diagnosis of human african trypanosomiasis. Clin Microbiol Rev 2005; 18:133-46. [PMID: 15653823 PMCID: PMC544181 DOI: 10.1128/cmr.18.1.133-146.2005] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human African trypanosomiasis (HAT) due to Trypanosoma brucei gambiense or T. b. rhodesiense remains highly prevalent in several rural areas of sub-Saharan Africa and is lethal if left untreated. Therefore, accurate tools are absolutely required for field diagnosis. For T. b. gambiense HAT, highly sensitive tests are available for serological screening but the sensitivity of parasitological confirmatory tests remains insufficient and needs to be improved. Screening for T. b. rhodesiense infection still relies on clinical features in the absence of serological tests available for field use. Ongoing research is opening perspectives for a new generation of field diagnostics. Also essential for both forms of HAT is accurate determination of the disease stage because of the high toxicity of melarsoprol, the drug most widely used during the neurological stage of the illness. Recent studies have confirmed the high accuracy of raised immunoglobulin M levels in the cerebrospinal fluid for the staging of T. b. gambiense HAT, and a promising simple assay (LATEX/IgM) is being tested in the field. Apart from the urgent need for better tools for the field diagnosis of this neglected disease, improved access to diagnosis and treatment for the population at risk remains the greatest challenge for the coming years.
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Affiliation(s)
- François Chappuis
- Travel and Migration Medicine Unit, Geneva University Hospital, 24 rue Micheli-du-Crest, 1211 Geneva 14, Switzerland.
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30
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MacLean L, Chisi JE, Odiit M, Gibson WC, Ferris V, Picozzi K, Sternberg JM. Severity of human african trypanosomiasis in East Africa is associated with geographic location, parasite genotype, and host inflammatory cytokine response profile. Infect Immun 2004; 72:7040-4. [PMID: 15557627 PMCID: PMC529158 DOI: 10.1128/iai.72.12.7040-7044.2004] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanisms underlying virulence in human African trypanosomiasis are poorly understood, although studies with experimental mice suggest that unregulated host inflammatory responses are associated with disease severity. We identified two trypanosomiasis foci with dramatically different disease virulence profiles. In Uganda, infections followed an acute profile with rapid progression to the late stage (meningoencephalitic infection) in the majority of patients (86.8%). In contrast, infections in Malawi were of a chronic nature, in which few patients progressed to the late stage (7.1%), despite infections of several months' duration. All infections were confirmed to be Trypanosoma brucei rhodesiense by testing for the presence of the serum resistance-associated (SRA) gene, but trypanosomes isolated from patients in Uganda or Malawi were distinguished by an SRA gene polymorphism. The two disease profiles were associated with markedly different levels of tumor necrosis factor alpha (TNF-alpha) and transforming growth factor beta (TGF-beta) in plasma. In Uganda but not Malawi early-stage TNF-alpha was elevated, while in Malawi but not Uganda early-stage TGF-beta was elevated. Thus, rapid disease progression in Uganda is associated with TNF-alpha-mediated inflammatory pathology, whereas in the milder disease observed in Malawi this may be ameliorated by counterinflammatory cytokines. These differing host responses may result either from differing virulence phenotypes of northern and southern trypanosomes or from immune response polymorphisms in the different host populations.
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Affiliation(s)
- Lorna MacLean
- School of Biological Sciences, University of Aberdeen, Zoology Building, Aberdeen AB24 2TZ, Scotland, United Kingdom
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31
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Becker S, Franco JR, Simarro PP, Stich A, Abel PM, Steverding D. Real-time PCR for detection of Trypanosoma brucei in human blood samples. Diagn Microbiol Infect Dis 2004; 50:193-9. [PMID: 15541605 DOI: 10.1016/j.diagmicrobio.2004.07.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Accepted: 07/07/2004] [Indexed: 11/17/2022]
Abstract
We have developed a real-time PCR assay for detection of Trypanosoma brucei DNA in human blood samples. The PCR was conducted with newly designed primers targeting the 177-bp repeat satellite DNA in T. brucei and with Sybr Green to monitor the amplicon accumulation. DNA purification using Chelex 100 resin was performed on blood samples collected on Whatman FTA cards and was shown to be a simple and quantitative method as revealed by real-time PCR. The detection limit of the assay was 100 trypanosomes per mL blood, corresponding to an analytical sensitivity of 0.1 genome equivalents. Trypanosome DNA was detected in all blood samples from sleeping sickness patients and, furthermore, the identity of the amplicon was confirmed in all assays by dissociation analysis. Although template DNA from blood samples was amplified with significantly lower efficiency than genomic DNA, similar efficiency between all assays ensured quantitative results. No amplicon product was obtained with samples from uninfected individuals. The results indicate that the real-time PCR assay described is a rapid and sensitive method suitable for the detection of T. brucei in human blood samples in routine clinical laboratory practice.
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Affiliation(s)
- Sven Becker
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
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32
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Jamonneau V, Solano P, Koffi M, Denizot M, Cuny G. [Contributions and limits of the diagnosis of human African trypanosomiasis]. Med Sci (Paris) 2004; 20:871-5. [PMID: 15461963 DOI: 10.1051/medsci/20042010871] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Human African trypanosomiasis, or sleeping sickness, is still a worrying problem in Africa. Sleeping sickness is a disease for which a systematic monitoring is necessary, particularly for the trypanosomiasis caused by Trypanosoma brucei gambiense, which is characterized by a long asymptomatic stage. In the absence of specific clinical signs, mass screening of populations remains the only way to control the disease and to avoid its spreading. The lack of sensitivity and specificity of the diagnosis tests classically used led to the development of molecular tools. PCR amplification of parasite specific sequences has considerably improved the diagnostic of the parasitic infection, the stage diagnosis as well as the post-therapeutic follow-up. But there are limits with a use in routine and research is still necessary to make PCR a real tool for control of sleeping sickness.
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Affiliation(s)
- Vincent Jamonneau
- Institut de recherche pour le développement (IRD), UR 035, Laboratoire de recherche et de coordination sur les trypanosomiases (LRCT), IRD/CIRAD, Campus international de Baillarguet, TA 207G, 34398 Montpellier 5, France.
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33
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Lejon V, Boelaert M, Jannin J, Moore A, Büscher P. The challenge of Trypanosoma brucei gambiense sleeping sickness diagnosis outside Africa. THE LANCET. INFECTIOUS DISEASES 2003; 3:804-8. [PMID: 14652206 DOI: 10.1016/s1473-3099(03)00834-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Sleeping sickness is a lethal African disease caused by parasites of the Trypanosoma brucei subspecies, which is transmitted by tsetse flies. Occasionally, patients are reported outside Africa. Diagnosis of such imported cases can be problematic when the infection is due to Trypanosoma brucei gambiense, the chronic form of sleeping sickness found in west and central Africa. The low number of trypanosomes in the blood and the non-specific, variable symptoms make the diagnosis difficult, particularly when the index of suspicion is low. When the trypanosomes have penetrated into the central nervous system, neuropathological signs become apparent but even at this stage, misdiagnosis is frequent. Rapid and correct diagnosis of sleeping sickness can avoid inappropriate or delayed treatment and even death of the patient. In this article, an overview on diagnosis of imported cases of T b gambiense sleeping sickness is given, and possible pitfalls in the diagnostic process are highlighted. Bioclinical parameters that should raise the suspicion of sleeping sickness in a patient who has been in west or central Africa are discussed. Techniques for diagnosis are reviewed. A clinician suspecting sleeping sickness should contact a national reference centre for tropical medicine in his or her country, or the WHO, Geneva, Switzerland, or the Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA, for clinical consultation and provision of specific diagnostic tests. Appropriate drugs for sleeping sickness treatment are also provided by WHO and the CDC.
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Affiliation(s)
- V Lejon
- Interdepartmental Research Group Neglected Diseases, Institute of Tropical Medicine, Antwerp, Belgium.
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34
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Agbo EC, Majiwa PAO, Büscher P, Claassen E, te Pas MFW. Trypanosoma brucei genomics and the challenge of identifying drug and vaccine targets. Trends Microbiol 2003; 11:322-9. [PMID: 12875816 DOI: 10.1016/s0966-842x(03)00151-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Eddy C Agbo
- Division of Animal Sciences, Institute for Animal Science and Health (ID-Lelystad), Edelhertweg 15, 8200 AB Lelystad, The Netherlands.
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35
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Jamonneau V, Solano P, Garcia A, Lejon V, Djé N, Miezan TW, N'Guessan P, Cuny G, Büscher P. Stage determination and therapeutic decision in human African trypanosomiasis: value of polymerase chain reaction and immunoglobulin M quantification on the cerebrospinal fluid of sleeping sickness patients in Côte d'Ivoire. Trop Med Int Health 2003; 8:589-94. [PMID: 12828540 DOI: 10.1046/j.1365-3156.2003.01079.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In human African trypanosomiasis (HAT), two disease stages are defined: the first, or haemo-lymphatic stage, and the second, or meningo-encephalitic stage. Stage determination forms the basis of therapeutic decision and is of prime importance, as the drug used to cure second-stage patients has considerable side-effects. However, the tests currently used for stage determination have low sensitivity or specificity. Two new tests for stage determination in the cerebrospinal fluid (CSF) were evaluated on 73 patients diagnosed with HAT in Côte d'Ivoire. The polymerase chain reaction (PCR) detecting trypanosome DNA (PCR/CSF) is an indirect test for trypanosome detection whereas the latex agglutination test detecting immunoglobulin M (LATEX/IgM) is an indicator for neuro-inflammation. Both tests were compared with classically used tests, double centrifugation and white blood cell count of the CSF. PCR/CSF appeared to be the most sensitive test (96%), and may be of use to improve stage determination. However, its value for therapeutic decision appears limited, as patients whose CSF was positive with PCR were successfully treated with pentamidine. This result confirms those of previous works that showed that some patients with trypanosomes in the CSF could be treated successfully with pentamidine. LATEX/IgM, which depending on the cut-off, showed lower sensitivity of 76% and 88%, but higher specificity of 83% and 71% for LATEX/IgM 16 and LATEX/IgM 8 respectively, appears more appropriate for therapeutic decision making.
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Affiliation(s)
- V Jamonneau
- Institut de Recherche pour le Développement, Institut Pierre Richet, Bouaké, Côte d'Ivoire, France
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36
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Radwanska M, Magez S, Perry-O'Keefe H, Stender H, Coull J, Sternberg JM, Büscher P, Hyldig-Nielsen JJ. Direct detection and identification of African trypanosomes by fluorescence in situ hybridization with peptide nucleic acid probes. J Clin Microbiol 2002; 40:4295-7. [PMID: 12409413 PMCID: PMC139669 DOI: 10.1128/jcm.40.11.4295-4297.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have developed a rapid and easy to perform fluorescence in situ hybridization test that allows specific identification of trypanosomes from the subgenus Trypanozoon, using peptide nucleic acid probes. Probes were designed to target subgenus-specific sequences on the multiple-copy 18S rRNA, greatly facilitating the detection of a single trypanosome.
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Affiliation(s)
- M Radwanska
- Department of Parasitology, Institute of Tropical Medicine, Antwerp, Belgium.
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37
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Gibson W. Epidemiology and diagnosis of African trypanosomiasis using DNA probes. Trans R Soc Trop Med Hyg 2002; 96 Suppl 1:S141-3. [PMID: 12055828 DOI: 10.1016/s0035-9203(02)90066-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The accurate identification of trypanosome species has been a challenging problem in the epidemiology of African trypanosomiasis, both human and animal. The last 10 years have seen great progress through the application of deoxyribonucleic acid (DNA) probe technology, although this has also revealed greater complexity than supposed. While a single repetitive DNA probe can identify all members of the subgenus Trypanosoma (Trypanozoon), including the human pathogens T. brucei gambiense and T. b. rhodesiense as well as the non-tsetse-transmitted trypanosomes T. evansi and T. equiperdum, at least 6 probes are needed to distinguish members of the subgenus Nannomonas, in which only 2 species, T. congolense and T. simiae, were previously recognized. Similarly, the subgenus Duttonella appears to consist of more than one species. Use of this battery of DNA probes to identify the trypanosomes carried by tsetse flies in the field has yielded some surprises about the accuracy (or inaccuracy) of previous identification methods. An unexpectedly high prevalence of mixed infections has been found in all the field studies carried out so far. The large number of infections that remain unidentified by the available probes suggests the existence of other, as yet unknown, trypanosome species. Limited use of the polymerase chain reaction has been made for diagnosis of human and animal trypanosomiasis, due to its high cost.
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Affiliation(s)
- Wendy Gibson
- School of Biological Sciences, University of Bristol, BS8 1UG, UK.
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38
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Welburn SC, Picozzi K, Fèvre EM, Coleman PG, Odiit M, Carrington M, Maudlin I. Identification of human-infective trypanosomes in animal reservoir of sleeping sickness in Uganda by means of serum-resistance-associated (SRA) gene. Lancet 2001; 358:2017-9. [PMID: 11755607 DOI: 10.1016/s0140-6736(01)07096-9] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The expansion of sleeping sickness caused by Trypanosoma brucei rhodesiense beyond its traditional focus in southeast Uganda has been linked with large-scale livestock restocking. To assess the risk presented to the human population by domestic livestock, human-infective T b rhodesiense must be distinguished from non-human-infective T brucei brucei, since both parasites can be present in cattle. We investigated the use of a simple genetic marker to characterise parasites collected from cattle in villages within the new sleeping sickness focus in Soroti District, Uganda. METHODS 70 T brucei sl samples of known human infectivity status collected from human beings and cattle in Tororo District, Uganda, from 1989 to 1991 were screened for the presence of the human-serum-resistance-associated (SRA) gene by conventional PCR. In 2000-01, blood samples from 200 randomly selected cattle in six villages and two markets in Soroti District were screened for T brucei sl parasites by PCR; positive samples were screened for the presence of the SRA gene. FINDINGS The SRA gene was present in all 29 samples from patients with sleeping sickness in Tororo District. Of the 41 samples collected from cattle at the same time, the SRA gene was present in the eight samples that tested resistant to human serum in vitro, whereas it was absent from all 33 isolates that were sensitive to human serum in vitro. Of the 200 cattle sampled in Soroti District, we estimated that up to 18% (95% CI 12-23) were infected with T b rhodesiense. INTERPRETATION Detection of the SRA gene could provide the basis for a simple diagnostic test to enable targeted control of T b rhodesiense in the domestic livestock reservoir, thereby reducing the public-health burden of sleeping sickness in east Africa.
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Affiliation(s)
- S C Welburn
- Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, EH25 9RG, Edinburgh, UK.
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Kabiri M, Steverding D. Trypanosoma evansi: demonstration of a transferrin receptor derived from expression site-associated genes 6 and 7. J Parasitol 2001; 87:1189-91. [PMID: 11695395 DOI: 10.1645/0022-3395(2001)087[1189:tedoat]2.0.co;2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
In Trypanosoma brucei, uptake of host transferrin is mediated by a heterodimeric, glycosylphosphatidylinositol-anchored receptor derived from the 2 expression site-associated genes 6 and 7 (ESAG6 and ESAG7). By using specific antibodies, it is shown here that T. evansi, a trypanosome species transmitted mechanically by biting flies, also expresses a transferrin receptor composed of ESAG6 and ESAG7. The cellular uptake of transferrin in T. evansi is completely inhibited with anti-T. brucei (ESAG6/7 heterodimer) antibodies. The demonstration of a functional ESAG6/7 transferrin receptor in T. evansi supports further its close relationship to T. brucei.
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Affiliation(s)
- M Kabiri
- Abteilung Parasitologie, Hygiene-Institut der Ruprecht-Karls-Universität, Heidelberg, Germany
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Sehgal RN, Jones HI, Smith TB. Host specificity and incidence of Trypanosoma in some African rainforest birds: a molecular approach. Mol Ecol 2001; 10:2319-27. [PMID: 11555273 DOI: 10.1046/j.1365-294x.2001.01339.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Studies of host-parasite interactions in birds have contributed greatly to our understanding of the evolution and ecology of disease. Here we employ molecular techniques to determine the incidence and study the host-specificity of parasitic trypanosomes in the African avifauna. We developed a polymerase chain reaction (PCR)-based diagnostic test that amplified the small subunit ribosomal RNA gene (SSU rRNA) of Trypanosoma from avian blood samples. This nested PCR assay complements and corroborates information obtained by the traditional method of blood smear analysis. The test was used to describe the incidence of trypanosomes in 479 host individuals representing 71 rainforest bird species from Cameroon, the Ivory Coast and Equatorial Guinea. Forty-two (59%) of these potential host species harboured trypanosomes and 189 individuals (35%) were infected. To examine host and geographical specificity, we examined the morphology and sequenced a portion of the SSU rRNA gene from representative trypanosomes drawn from different hosts and collecting locations. In traditional blood smear analyses we identified two trypanosome morphospecies, T. avium and T. everetti. Our molecular and morphological results were congruent in that these two morphospecies had highly divergent SSU rRNA sequences, but the molecular assay also identified cryptic variation in T. avium, in which we found seven closely allied haplotypes. The pattern of sequence diversity within T. avium provides evidence for widespread trypanosome mixing across avian host taxa and across geographical locations. For example, T. avium lineages with identical haplotypes infected birds from different families, whereas single host species were infected by T. avium lineages with different haplotypes. Furthermore, some conspecific hosts from geographically distant sampling locations were infected with the same trypanosome lineage, but other individuals from those locations harboured different trypanosome lineages. This apparent lack of host or geographical specificity may have important consequences for the evolutionary and ecological interactions between parasitic trypanosomes and their avian hosts.
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Affiliation(s)
- R N Sehgal
- Center for Tropical Research, Department of Biology, San Francisco State University, 1600 Holloway, San Francisco, CA, 94132, USA.
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Penchenier L, Simo G, Grébaut P, Nkinin S, Laveissière C, Herder S. Diagnosis of human trypanosomiasis, due to Trypanosoma brucei gambiense in central Africa, by the polymerase chain reaction. Trans R Soc Trop Med Hyg 2000; 94:392-4. [PMID: 11127241 DOI: 10.1016/s0035-9203(00)90116-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
During a mass screening of sleeping sickness conducted in 1998 and 1999, and involving 27,932 persons in Cameroon and the Central African Republic, we tested the polymerase chain reaction (PCR) on whole blood for the diagnosis of human African trypanosomiasis due to Trypanosoma brucei gambiense. The 1858 samples obtained were from 4 groups: 155 infected patients, 1432 serological suspects detected by the card agglutination test for trypanosomiasis (CATT), 222 negative controls living in the prospected area (negative with the CATT and parasitological methods), and 49 negative controls (CATT and parasitological methods) and unexposed to the disease (Europeans). The technique of DNA extraction used made it possible to preserve the blood samples in the field. The primers used were specific for T. brucei s.l. Only 1 patient was PCR negative, and 3 of the negative controls, exposed to the disease, were PCR positive. Among the 1432 serological suspects, only 50 were PCR positive. During the 6-month follow-up after the surveys, the 3 negative controls, who were initially positive by PCR, were found to be negative. These initial positive PCR results are unlikely to have been due to a cross-reaction with T. brucei brucei, which is non-pathogenic for man, but are more likely to have resulted from a mislabelling of sample tubes. All control individuals, exposed or not to the disease, were negative by PCR. The PCR-negative patient was possibly a registration error. Among 50 PCR positive serological suspects, 39 of them were re-examined. Five were found to be positive by the kit for in-vitro isolation of trypanosomes, representing an increase in patients of almost 13%. At the end of the study, 160 patients were diagnosed, and the PCR was positive for 159 of them (99.4%). Moreover, the PCR made it possible to reduce the number of suspects to be re-examined (50 instead of 1432; a reduction of 96.5%).
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