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Crump RE, Aliee M, Sutherland SA, Huang CI, Crowley EH, Spencer SEF, Keeling MJ, Shampa C, Mwamba Miaka E, Rock KS. Modelling timelines to elimination of sleeping sickness in the Democratic Republic of Congo, accounting for possible cryptic human and animal transmission. Parasit Vectors 2024; 17:332. [PMID: 39123265 PMCID: PMC11313002 DOI: 10.1186/s13071-024-06404-4] [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: 03/20/2024] [Accepted: 07/13/2024] [Indexed: 08/12/2024] Open
Abstract
BACKGROUND Sleeping sickness (gambiense human African trypanosomiasis, gHAT) is a vector-borne disease targeted for global elimination of transmission (EoT) by 2030. There are, however, unknowns that have the potential to hinder the achievement and measurement of this goal. These include asymptomatic gHAT infections (inclusive of the potential to self-cure or harbour skin-only infections) and whether gHAT infection in animals can contribute to the transmission cycle in humans. METHODS Using modelling, we explore how cryptic (undetected) transmission impacts the monitoring of progress towards and the achievement of the EoT goal. We have developed gHAT models that include either asymptomatic or animal transmission, and compare these to a baseline gHAT model without either of these transmission routes, to explore the potential role of cryptic infections on the EoT goal. Each model was independently calibrated to five different health zones in the Democratic Republic of the Congo (DRC) using available historical human case data for 2000-2020 (obtained from the World Health Organization's HAT Atlas). We applied a novel Bayesian sequential updating approach for the asymptomatic model to enable us to combine statistical information about this type of transmission from each health zone. RESULTS Our results suggest that, when matched to past case data, we estimated similar numbers of new human infections between model variants, although human infections were slightly higher in the models with cryptic infections. We simulated the continuation of screen-confirm-and-treat interventions, and found that forward projections from the animal and asymptomatic transmission models produced lower probabilities of EoT than the baseline model; however, cryptic infections did not prevent EoT from being achieved eventually under this approach. CONCLUSIONS This study is the first to simulate an (as-yet-to-be available) screen-and-treat strategy and found that removing a parasitological confirmation step was predicted to have a more noticeable benefit to transmission reduction under the asymptomatic model compared with the others. Our simulations suggest vector control could greatly impact all transmission routes in all models, although this resource-intensive intervention should be carefully prioritised.
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Affiliation(s)
- Ronald E Crump
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
| | - Maryam Aliee
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
| | - Samuel A Sutherland
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Warwick Medical School, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Ching-I Huang
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
| | - Emily H Crowley
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
| | - Simon E F Spencer
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Department of Statistics, University of Warwick, Academic Loop Road, Coventry, UK
| | - Matt J Keeling
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK
- School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Chansy Shampa
- Programme National de Lutte Contre la Trypanosomiase Humaine Africaine (PNLTHA)-DRC, Kinshasa, Democratic Republic of Congo
| | - Erick Mwamba Miaka
- Programme National de Lutte Contre la Trypanosomiase Humaine Africaine (PNLTHA)-DRC, Kinshasa, Democratic Republic of Congo
| | - Kat S Rock
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, CV4 7AL, Coventry, UK.
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, UK.
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Soumah AM, Camara M, Kaboré JW, Sadissou I, Ilboudo H, Travaillé C, Camara O, Tichit M, Kaboré J, Boiro S, Crouzols A, Ngoune JMT, Hardy D, Camara A, Jamonneau V, MacLeod A, Bart JM, Camara M, Bucheton B, Rotureau B. Prevalence of dermal trypanosomes in suspected and confirmed cases of gambiense human African trypanosomiasis in Guinea. PLoS Negl Trop Dis 2024; 18:e0012436. [PMID: 39159265 PMCID: PMC11361743 DOI: 10.1371/journal.pntd.0012436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 08/29/2024] [Accepted: 08/05/2024] [Indexed: 08/21/2024] Open
Abstract
The skin is an anatomical reservoir for African trypanosomes, yet the prevalence of extravascular parasite carriage in the population at risk of gambiense Human African Trypanosomiasis (gHAT) remains unclear. Here, we conducted a prospective observational cohort study in the HAT foci of Forecariah and Boffa, Republic of Guinea. Of the 18,916 subjects serologically screened for gHAT, 96 were enrolled into our study. At enrolment and follow-up visits, participants underwent a dermatological examination and had blood samples and superficial skin snip biopsies taken for examination by molecular and immuno-histological methods. In seropositive individuals, dermatological symptoms were significantly more frequent as compared to seronegative controls. Trypanosoma brucei DNA was detected in the blood of 67% of confirmed cases (22/33) and 9% of unconfirmed seropositive individuals (3/32). However, parasites were detected in the extravascular dermis of up to 71% of confirmed cases (25/35) and 41% of unconfirmed seropositive individuals (13/32) by PCR and/or immuno-histochemistry. Six to twelve months after treatment, trypanosome detection in the skin dropped to 17% of confirmed cases (5/30), whereas up to 25% of unconfirmed, hence untreated, seropositive individuals (4/16) were still found positive. Dermal trypanosomes were observed in subjects from both transmission foci, however, the occurrence of pruritus and the PCR positivity rates were significantly higher in unconfirmed seropositive individuals in Forecariah. The lower sensitivity of superficial skin snip biopsies appeared critical for detecting trypanosomes in the basal dermis. These results are discussed in the context of the planned elimination of gHAT.
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Affiliation(s)
- Alseny M’mah Soumah
- Programme National de Lutte contre les Maladies Tropicales Négligées, Ministère de la Santé, Conakry, Guinea
| | - Mariame Camara
- Programme National de Lutte contre les Maladies Tropicales Négligées, Ministère de la Santé, Conakry, Guinea
| | - Justin Windingoudi Kaboré
- Programme National de Lutte contre les Maladies Tropicales Négligées, Ministère de la Santé, Conakry, Guinea
| | - Ibrahim Sadissou
- INTERTRYP, Université de Montpellier, CIRAD, IRD, Montpellier, France
| | - Hamidou Ilboudo
- INTERTRYP, Université de Montpellier, CIRAD, IRD, Montpellier, France
- Institut de Recherche en Sciences de la Santé - Unité de Recherche Clinique de Nanoro, Nanoro, Burkina-Faso
| | - Christelle Travaillé
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
| | - Oumou Camara
- Programme National de Lutte contre les Maladies Tropicales Négligées, Ministère de la Santé, Conakry, Guinea
| | - Magali Tichit
- Histopathology Core Facility, Institut Pasteur, Université Paris Cité, Paris, France
| | - Jacques Kaboré
- Unité de recherches sur les bases biologiques de la lutte intégrée, Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
| | - Salimatou Boiro
- Parasitology Unit, Institut Pasteur of Guinea, Conakry, Guinea
| | - Aline Crouzols
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
| | - Jean Marc Tsagmo Ngoune
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
| | - David Hardy
- Histopathology Core Facility, Institut Pasteur, Université Paris Cité, Paris, France
| | - Aïssata Camara
- Parasitology Unit, Institut Pasteur of Guinea, Conakry, Guinea
| | - Vincent Jamonneau
- INTERTRYP, Université de Montpellier, CIRAD, IRD, Montpellier, France
| | - Annette MacLeod
- Wellcome Centre for Integrative Parasitology, College of Medical, Veterinary, and Life Sciences, Henry Wellcome Building for Comparative Medical Sciences, Glasgow, Scotland, United Kingdom
| | - Jean-Mathieu Bart
- Programme National de Lutte contre les Maladies Tropicales Négligées, Ministère de la Santé, Conakry, Guinea
- INTERTRYP, Université de Montpellier, CIRAD, IRD, Montpellier, France
| | - Mamadou Camara
- Programme National de Lutte contre les Maladies Tropicales Négligées, Ministère de la Santé, Conakry, Guinea
| | - Bruno Bucheton
- Programme National de Lutte contre les Maladies Tropicales Négligées, Ministère de la Santé, Conakry, Guinea
- INTERTRYP, Université de Montpellier, CIRAD, IRD, Montpellier, France
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur, Université Paris Cité, Paris, France
- Parasitology Unit, Institut Pasteur of Guinea, Conakry, Guinea
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Amisigo CM, Amegatcher G, Sunter JD, Gwira TM. Adipose and skin distribution of African trypanosomes in natural animal infections. Parasit Vectors 2024; 17:215. [PMID: 38734633 PMCID: PMC11088761 DOI: 10.1186/s13071-024-06277-7] [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: 02/15/2024] [Accepted: 04/10/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND Animal African trypanosomiasis, which is caused by different species of African trypanosomes, is a deadly disease in livestock. Although African trypanosomes are often described as blood-borne parasites, there have been recent reappraisals of the ability of these parasites to reside in a wide range of tissues. However, the majority of those studies were conducted on non-natural hosts infected with only one species of trypanosome, and it is unclear whether a similar phenomenon occurs during natural animal infections, where multiple species of these parasites may be present. METHODS The infective trypanosome species in the blood and other tissues (adipose and skin) of a natural host (cows, goats and sheep) were determined using a polymerase chain reaction-based diagnostic. RESULTS The animals were found to harbour multiple species of trypanosomes. Different patterns of distribution were observed within the host tissues; for instance, in some animals, the blood was positive for the DNA of one species of trypanosome and the skin and adipose were positive for the DNA of another species. Moreover, the rate of detection of trypanosome DNA was highest for skin adipose and lowest for the blood. CONCLUSIONS The findings reported here emphasise the complexity of trypanosome infections in a natural setting, and may indicate different tissue tropisms between the different parasite species. The results also highlight the need to include adipose and skin tissues in future diagnostic and treatment strategies.
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Affiliation(s)
- Cynthia Mmalebna Amisigo
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Gloria Amegatcher
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana
| | - Jack D Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Theresa Manful Gwira
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana.
- Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Accra, Ghana.
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Rock KS, Chapman LAC, Dobson AP, Adams ER, Hollingsworth TD. The Hidden Hand of Asymptomatic Infection Hinders Control of Neglected Tropical Diseases: A Modeling Analysis. Clin Infect Dis 2024; 78:S175-S182. [PMID: 38662705 PMCID: PMC11045017 DOI: 10.1093/cid/ciae096] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Neglected tropical diseases are responsible for considerable morbidity and mortality in low-income populations. International efforts have reduced their global burden, but transmission is persistent and case-finding-based interventions rarely target asymptomatic individuals. METHODS We develop a generic mathematical modeling framework for analyzing the dynamics of visceral leishmaniasis in the Indian sub-continent (VL), gambiense sleeping sickness (gHAT), and Chagas disease and use it to assess the possible contribution of asymptomatics who later develop disease (pre-symptomatics) and those who do not (non-symptomatics) to the maintenance of infection. Plausible interventions, including active screening, vector control, and reduced time to detection, are simulated for the three diseases. RESULTS We found that the high asymptomatic contribution to transmission for Chagas and gHAT and the apparently high basic reproductive number of VL may undermine long-term control. However, the ability to treat some asymptomatics for Chagas and gHAT should make them more controllable, albeit over relatively long time periods due to the slow dynamics of these diseases. For VL, the toxicity of available therapeutics means the asymptomatic population cannot currently be treated, but combining treatment of symptomatics and vector control could yield a quick reduction in transmission. CONCLUSIONS Despite the uncertainty in natural history, it appears there is already a relatively good toolbox of interventions to eliminate gHAT, and it is likely that Chagas will need improvements to diagnostics and their use to better target pre-symptomatics. The situation for VL is less clear, and model predictions could be improved by additional empirical data. However, interventions may have to improve to successfully eliminate this disease.
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Affiliation(s)
- Kat S Rock
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Coventry, United Kingdom
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
| | - Lloyd A C Chapman
- Department of Mathematics and Statistics, Lancaster University, Lancaster, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Andrew P Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
- Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Emily R Adams
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - T Déirdre Hollingsworth
- Nuffield Department of Medicine, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
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Davis CN, Crump RE, Sutherland SA, Spencer SEF, Corbella A, Chansy S, Lebuki J, Miaka EM, Rock KS. Comparison of stochastic and deterministic models for gambiense sleeping sickness at different spatial scales: A health area analysis in the DRC. PLoS Comput Biol 2024; 20:e1011993. [PMID: 38557869 PMCID: PMC11008881 DOI: 10.1371/journal.pcbi.1011993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 04/11/2024] [Accepted: 03/11/2024] [Indexed: 04/04/2024] Open
Abstract
The intensification of intervention activities against the fatal vector-borne disease gambiense human African trypanosomiasis (gHAT, sleeping sickness) in the last two decades has led to a large decline in the number of annually reported cases. However, while we move closer to achieving the ambitious target of elimination of transmission (EoT) to humans, pockets of infection remain, and it becomes increasingly important to quantitatively assess if different regions are on track for elimination, and where intervention efforts should be focused. We present a previously developed stochastic mathematical model for gHAT in the Democratic Republic of Congo (DRC) and show that this same formulation is able to capture the dynamics of gHAT observed at the health area level (approximately 10,000 people). This analysis was the first time any stochastic gHAT model has been fitted directly to case data and allows us to better quantify the uncertainty in our results. The analysis focuses on utilising a particle filter Markov chain Monte Carlo (MCMC) methodology to fit the model to the data from 16 health areas of Mosango health zone in Kwilu province as a case study. The spatial heterogeneity in cases is reflected in modelling results, where we predict that under the current intervention strategies, the health area of Kinzamba II, which has approximately one third of the health zone's cases, will have the latest expected year for EoT. We find that fitting the analogous deterministic version of the gHAT model using MCMC has substantially faster computation times than fitting the stochastic model using pMCMC, but produces virtually indistinguishable posterior parameterisation. This suggests that expanding health area fitting, to cover more of the DRC, should be done with deterministic fits for efficiency, but with stochastic projections used to capture both the parameter and stochastic variation in case reporting and elimination year estimations.
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Affiliation(s)
- Christopher N. Davis
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- School of Life Sciences, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Ronald E. Crump
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Samuel A. Sutherland
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Warwick Medical School, The University of Warwick, Coventry, United Kingdom
| | - Simon E. F. Spencer
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Department of Statistics, The University of Warwick, Coventry, United Kingdom
| | - Alice Corbella
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Department of Statistics, The University of Warwick, Coventry, United Kingdom
| | - Shampa Chansy
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Junior Lebuki
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Kat S. Rock
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
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Franco JR, Priotto G, Paone M, Cecchi G, Ebeja AK, Simarro PP, Sankara D, Metwally SBA, Argaw DD. The elimination of human African trypanosomiasis: Monitoring progress towards the 2021-2030 WHO road map targets. PLoS Negl Trop Dis 2024; 18:e0012111. [PMID: 38626188 PMCID: PMC11073784 DOI: 10.1371/journal.pntd.0012111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 05/06/2024] [Accepted: 03/26/2024] [Indexed: 04/18/2024] Open
Abstract
BACKGROUND Human African trypanosomiasis (HAT) is a neglected tropical disease that usually occurs in rural areas in sub-Saharan Africa. It caused devastating epidemics during the 20th century. Sustained, coordinated efforts by different stakeholders working with national sleeping sickness control programmes (NSSCPs) succeeded in controlling the disease and reducing the number of cases to historically low levels. In 2012, WHO targeted the elimination of the disease as a public health problem by 2020. This goal has been reached and a new ambitious target was stated in the WHO road map for NTDs 2021-2030 and endorsed by the 73rd World Health Assembly: the elimination of gambiense HAT transmission (i.e. reducing the number of reported cases to zero). The interruption of transmission was not considered as an achievable goal for rhodesiense HAT, as it would require vast veterinary interventions rather than actions at the public health level. METHODOLOGY/PRINCIPAL FINDINGS Data reported to WHO by NSSCPs were harmonized, verified, georeferenced and included in the atlas of HAT. A total of 802 cases were reported in 2021 and 837 in 2022. This is below the target for elimination as a public health problem at the global level (< 2000 HAT cases/year); 94% of the cases were caused by infection with T. b. gambiense. The areas reporting ≥ 1 HAT case/10 000 inhabitants/year in 2018-2022 cover a surface of 73 134 km2, with only 3013 km2 at very high or high risk. This represents a reduction of 90% from the baseline figure for 2000-2004, the target set for the elimination of HAT as a public health problem. For the surveillance of the disease, 4.5 million people were screened for gambiense HAT with serological tests in 2021-2022, 3.6 million through active screening and 0.9 million by passive screening. In 2021 and 2022 the elimination of HAT as a public health problem was validated in Benin, Uganda, Equatorial Guinea and Ghana for gambiense HAT and in Rwanda for rhodesiense HAT. To reach the next goal of elimination of transmission of gambiense HAT, countries have to report zero cases of human infection with T. b. gambiense for a period of at least 5 consecutive years. The criteria and procedures to verify elimination of transmission have been recently published by WHO. CONCLUSIONS/SIGNIFICANCE HAT elimination as a public health problem has been reached at global level, with seven countries already validated as having reached this goal. This achievement was made possible by the work of NSSCPs, supported by different public and private partners, and coordinated by WHO. The new challenging goal now is to reach zero cases by 2030. To reach this goal is crucial to maintain the engagement and support of donors and stakeholders and to keep the involvement and coordination of all partners. Along with the focus on elimination of transmission of gambiense HAT, it is important not to neglect rhodesiense HAT, which is targeted for elimination as a public health problem in the WHO road map for NTDs 2021-2030.
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Affiliation(s)
- Jose R. Franco
- World Health Organization, Global Neglected Tropical Diseases Programme, Prevention, Treatment and Care Unit, Geneva, Switzerland
| | - Gerardo Priotto
- World Health Organization, Global Neglected Tropical Diseases Programme, Prevention, Treatment and Care Unit, Geneva, Switzerland
| | - Massimo Paone
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Agustin Kadima Ebeja
- World Health Organization, Regional Office for Africa, Communicable Disease Unit, Brazzaville, Congo
| | - Pere P. Simarro
- Consultant, World Health Organization, Global Neglected Tropical Diseases Programme, Innovative and Intensified Disease Management Unit, Geneva, Switzerland
| | - Dieudonne Sankara
- World Health Organization, Global Neglected Tropical Diseases Programme, Prevention, Treatment and Care Unit, Geneva, Switzerland
| | - Samia B. A. Metwally
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Daniel Dagne Argaw
- World Health Organization, Global Neglected Tropical Diseases Programme, Prevention, Treatment and Care Unit, Geneva, Switzerland
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Chadwick FJ, Haydon DT, Husmeier D, Ovaskainen O, Matthiopoulos J. LIES of omission: complex observation processes in ecology. Trends Ecol Evol 2024; 39:368-380. [PMID: 37949794 DOI: 10.1016/j.tree.2023.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 10/13/2023] [Accepted: 10/16/2023] [Indexed: 11/12/2023]
Abstract
Advances in statistics mean that it is now possible to tackle increasingly sophisticated observation processes. The intricacies and ambitious scale of modern data collection techniques mean that this is now essential. Methodological research to make inference about the biological process while accounting for the observation process has expanded dramatically, but solutions are often presented in field-specific terms, limiting our ability to identify commonalities between methods. We suggest a typology of observation processes that could improve translation between fields and aid methodological synthesis. We propose the LIES framework (defining observation processes in terms of issues of Latency, Identifiability, Effort and Scale) and illustrate its use with both simple examples and more complex case studies.
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Affiliation(s)
- Fergus J Chadwick
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK; Centre for Research Into Ecological and Environmental Monitoring, School of Mathematics and Statistics, University of St Andrews, St. Andrews, Scotland, UK.
| | - Daniel T Haydon
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Dirk Husmeier
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8TA, UK
| | - Otso Ovaskainen
- Department of Biological and Environmental Science, P.O. Box 35 FI-40014, University of Jyväskylä, Jyväskylä, Finland
| | - Jason Matthiopoulos
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
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Juban P, Bart JM, Ségard A, Jamonneau V, Ravel S. Trypanosoma brucei gambiense group 2 experimental in vivo life cycle: from procyclic to bloodstream form. Parasite 2024; 31:15. [PMID: 38520091 PMCID: PMC10960050 DOI: 10.1051/parasite/2024009] [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: 10/27/2023] [Accepted: 02/06/2024] [Indexed: 03/25/2024] Open
Abstract
Trypanosoma brucei gambiense (Tbg) group 2 is a subgroup of trypanosomes able to infect humans and is found in West and Central Africa. Unlike other agents causing sleeping sickness, such as Tbg group 1 and Trypanosoma brucei rhodesiense, Tbg2 lacks the typical molecular markers associated with resistance to human serum. Only 36 strains of Tbg2 have been documented, and therefore, very limited research has been conducted despite their zoonotic nature. Some of these strains are only available in their procyclic form, which hinders human serum resistance assays and mechanistic studies. Furthermore, the understanding of Tbg2's potential to infect tsetse flies and mammalian hosts is limited. In this study, 165 Glossina palpalis gambiensis flies were experimentally infected with procyclic Tbg2 parasites. It was found that 35 days post-infection, 43 flies out of the 80 still alive were found to be Tbg2 PCR-positive in the saliva. These flies were able to infect 3 out of the 4 mice used for blood-feeding. Dissection revealed that only six flies in fact carried mature infections in their midguts and salivary glands. Importantly, a single fly with a mature infection was sufficient to infect a mammalian host. This Tbg2 transmission success confirms that Tbg2 strains can establish in tsetse flies and infect mammalian hosts. This study describes an effective in vivo protocol for transforming Tbg2 from procyclic to bloodstream form, reproducing the complete Tbg2 cycle from G. p. gambiensis to mice. These findings provide valuable insights into Tbg2's host infectivity, and will facilitate further research on mechanisms of human serum resistance.
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Affiliation(s)
- Paola Juban
- INTERTRYP, Université de Montpellier, Cirad, IRD Montpellier France
| | | | - Adeline Ségard
- INTERTRYP, Université de Montpellier, Cirad, IRD Montpellier France
| | | | - Sophie Ravel
- INTERTRYP, Université de Montpellier, Cirad, IRD Montpellier France
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De Niz M, Frachon E, Gobaa S, Bastin P. Spatial confinement of Trypanosoma brucei in microfluidic traps provides a new tool to study free swimming parasites. PLoS One 2023; 18:e0296257. [PMID: 38134042 PMCID: PMC10745224 DOI: 10.1371/journal.pone.0296257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Trypanosoma brucei is the causative agent of African trypanosomiasis and is transmitted by the tsetse fly (Glossina spp.). All stages of this extracellular parasite possess a single flagellum that is attached to the cell body and confers a high degree of motility. While several stages are amenable to culture in vitro, longitudinal high-resolution imaging of free-swimming parasites has been challenging, mostly due to the rapid flagellar beating that constantly twists the cell body. Here, using microfabrication, we generated various microfluidic devices with traps of different geometrical properties. Investigation of trap topology allowed us to define the one most suitable for single T. brucei confinement within the field of view of an inverted microscope while allowing the parasite to remain motile. Chips populated with V-shaped traps allowed us to investigate various phenomena in cultured procyclic stage wild-type parasites, and to compare them with parasites whose motility was altered upon knockdown of a paraflagellar rod component. Among the properties that we investigated were trap invasion, parasite motility, and the visualization of organelles labelled with fluorescent dyes. We envisage that this tool we have named "Tryp-Chip" will be a useful tool for the scientific community, as it could allow high-throughput, high-temporal and high-spatial resolution imaging of free-swimming T. brucei parasites.
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Affiliation(s)
- Mariana De Niz
- Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Université de Paris, INSERM U1201, Paris, France
| | - Emmanuel Frachon
- Institut Pasteur, Université de Paris, Biomaterials and Microfluidics Core Facility, Paris, France
| | - Samy Gobaa
- Institut Pasteur, Université de Paris, Biomaterials and Microfluidics Core Facility, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Université de Paris, INSERM U1201, Paris, France
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10
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Meisner J, Kato A, Lemerani M, Mwamba Miaka E, Ismail Taban A, Wakefield J, Rowhani-Rahbar A, Pigott DM, Mayer J, Rabinowitz PM. Livestock, pathogens, vectors, and their environment: A causal inference-based approach to estimating the pathway-specific effect of livestock on human African trypanosomiasis risk. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0002543. [PMID: 37967087 PMCID: PMC10651035 DOI: 10.1371/journal.pgph.0002543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/09/2023] [Indexed: 11/17/2023]
Abstract
Livestock are important reservoirs for many zoonotic diseases, however the effects of livestock on human and environmental health extend well beyond direct disease transmission. In this retrospective ecological cohort study we use pre-existing data and the parametric g-formula, which imputes potential outcomes to quantify mediation, to estimate three hypothesized mechanisms by which livestock can influence human African trypanosomiasis (HAT) risk: the reservoir effect, where infected cattle and pigs are a source of infection to humans; the zooprophylactic effect, where preference for livestock hosts exhibited by the tsetse fly vector of HAT means that their presence protects humans from infection; and the environmental change effect, where livestock keeping activities modify the environment in such a way that habitat suitability for tsetse flies, and in turn human infection risk, is reduced. We conducted this study in four high burden countries: at the point level in Uganda, Malawi, and Democratic Republic of Congo (DRC), and at the county level in South Sudan. Our results indicate cattle and pigs play a reservoir role for the rhodesiense form (rHAT) in Uganda (rate ratio (RR) 1.68, 95% CI 0.84, 2.82 for cattle; RR 2.16, 95% CI 1.18, 3.05 for pigs), however zooprophylaxis outweighs this effect for rHAT in Malawi (RR 0.85, 95% CI 0.68, 1.00 for cattle, RR 0.38, 95% CI 0.21, 0.69 for pigs). For the gambiense form (gHAT) we found evidence that pigs may be a competent reservoir (RR 1.15, 95% CI 0.92, 1.72 in Uganda; RR 1.25, 95% CI 1.11, 1.42 in DRC). Statistical significance was reached for rHAT in Malawi (pigs and cattle) and Uganda (pigs only) and for gHAT in DRC (pigs and cattle). We did not find compelling evidence of an environmental change effect (all effect sizes close to 1).
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Affiliation(s)
- Julianne Meisner
- Center for One Health Research, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | | | - Marshall Lemerani
- Trypanosomiasis Control Program, Ministry of Health, Lilongwe, Malawi
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, Democratic Republic of Congo
| | | | - Jonathan Wakefield
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
- Department of Statistics, University of Washington, Seattle, Washington, United States of America
| | - Ali Rowhani-Rahbar
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - David M. Pigott
- Department of Health Metrics Sciences, University of Washington, Seattle, Washington, United States of America
| | - Jonathan Mayer
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Peter M. Rabinowitz
- Center for One Health Research, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America
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11
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Ilboudo K, Boulangé A, Hounyèmè RE, Gimonneau G, Kaboré J, Belem AGM, Desquesnes M, Lejon V, Koffi M, Jamonneau V, Thévenon S. Performance of diagnostic tests for Trypanosoma brucei brucei in experimentally infected pigs. PLoS Negl Trop Dis 2023; 17:e0011730. [PMID: 37943881 PMCID: PMC10662723 DOI: 10.1371/journal.pntd.0011730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 11/21/2023] [Accepted: 10/16/2023] [Indexed: 11/12/2023] Open
Abstract
Animal African trypanosomosis is an important vector-borne disease of livestock in sub-Saharan Africa. Pigs seem relatively tolerant to trypanosome infection and could act as a reservoir of trypanosomes affecting animals and humans. Our ability to reliably detect trypanosome infection in pigs depends on the performance of diagnostic tools, which is not well known. In pigs experimentally infected with Trypanosoma brucei brucei, we evaluated the performance of parasitological Buffy Coat Technique (BCT), two molecular (TBR and 5.8S PCR) and four serological tests (CATT, HAT Sero-K-Set rapid diagnostic test-RDT, indirect ELISA, immune trypanolysis). Most diagnostic tests showed high specificity, estimated at 100% (95% CI = 74-100%) with the exception of CATT and RDT whose specificity varied between 100% (95% CI = 74-100%) to 50% (95% CI = 7-93%) during the experiment. The sensitivity of each test fluctuated over the course of the infection. The percentage of positive BCT over the infection (30%) was lower than of positive PCR (56% and 62%, depending on primers). Among the serological tests, the percentage of positive tests was 97%, 96%, 86% and 84% for RDT, ELISA, immune trypanolysis and CATT, respectively. Fair agreement was observed between both molecular tests (κ = 0.36). Among the serological tests, the agreement between the ELISA and the RDT was substantial (κ = 0.65). Our results on the T.b. brucei infection model suggest that serological techniques are efficient in detecting the chronic phase of infection, PCR is able to detect positive samples several months after parasites inoculation while BCT becomes negative. BCT examination and RDT are useful to get a quick information in the field, and BCT can be used for treatment decision. ELISA appears most suited for epidemiological studies. The selection of diagnostic tests for trypanosomosis in pigs depends on the context, the objectives and the available resources.
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Affiliation(s)
- Kadidiata Ilboudo
- Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
- Unité de Formation et de Recherche en Sciences de la Vie et de la Terre, Université Nazi Boni, Bobo-Dioulasso, Burkina Faso
| | - Alain Boulangé
- Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
- CIRAD, UMR INTERTRYP, Montpellier, France
- INTERTRYP, University of Montpellier, CIRAD, IRD, Montpellier, France
| | - Robert Eustache Hounyèmè
- Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Geoffrey Gimonneau
- CIRAD, UMR INTERTRYP, Montpellier, France
- INTERTRYP, University of Montpellier, CIRAD, IRD, Montpellier, France
- Laboratoire National d’Élevage et de Recherches Vétérinaires, Service de Bio-Écologie et Pathologies Parasitaires, Dakar—Hann, Sénégal
| | - Jacques Kaboré
- Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
- Unité de Formation et de Recherche en Sciences de la Vie et de la Terre, Université Nazi Boni, Bobo-Dioulasso, Burkina Faso
| | | | - Marc Desquesnes
- CIRAD, UMR INTERTRYP, Montpellier, France
- INTERTRYP, University of Montpellier, CIRAD, IRD, Montpellier, France
- National Veterinary School of Toulouse (ENVT), Toulouse, France
| | - Veerle Lejon
- INTERTRYP, University of Montpellier, CIRAD, IRD, Montpellier, France
| | - Mathurin Koffi
- Laboratoire de Biodiversité et Gestion des Ecosystèmes Tropicaux, Unité de Recherche en Génétique et Épidémiologie Moléculaire, UFR Environnement, Université Jean Lorougnon Guédé, Daloa, Côte d’Ivoire
| | - Vincent Jamonneau
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
- INTERTRYP, University of Montpellier, CIRAD, IRD, Montpellier, France
| | - Sophie Thévenon
- CIRAD, UMR INTERTRYP, Montpellier, France
- INTERTRYP, University of Montpellier, CIRAD, IRD, Montpellier, France
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12
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Jamabo M, Mahlalela M, Edkins AL, Boshoff A. Tackling Sleeping Sickness: Current and Promising Therapeutics and Treatment Strategies. Int J Mol Sci 2023; 24:12529. [PMID: 37569903 PMCID: PMC10420020 DOI: 10.3390/ijms241512529] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/27/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
Human African trypanosomiasis is a neglected tropical disease caused by the extracellular protozoan parasite Trypanosoma brucei, and targeted for eradication by 2030. The COVID-19 pandemic contributed to the lengthening of the proposed time frame for eliminating human African trypanosomiasis as control programs were interrupted. Armed with extensive antigenic variation and the depletion of the B cell population during an infectious cycle, attempts to develop a vaccine have remained unachievable. With the absence of a vaccine, control of the disease has relied heavily on intensive screening measures and the use of drugs. The chemotherapeutics previously available for disease management were plagued by issues such as toxicity, resistance, and difficulty in administration. The approval of the latest and first oral drug, fexinidazole, is a major chemotherapeutic achievement for the treatment of human African trypanosomiasis in the past few decades. Timely and accurate diagnosis is essential for effective treatment, while poor compliance and resistance remain outstanding challenges. Drug discovery is on-going, and herein we review the recent advances in anti-trypanosomal drug discovery, including novel potential drug targets. The numerous challenges associated with disease eradication will also be addressed.
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Affiliation(s)
- Miebaka Jamabo
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| | - Maduma Mahlalela
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
| | - Adrienne L. Edkins
- Department of Biochemistry and Microbiology, Biomedical Biotechnology Research Centre (BioBRU), Rhodes University, Makhanda 6139, South Africa;
| | - Aileen Boshoff
- Biotechnology Innovation Centre, Rhodes University, Makhanda 6139, South Africa; (M.J.); (M.M.)
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13
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Kaba D, Koffi M, Kouakou L, N’Gouan EK, Djohan V, Courtin F, N’Djetchi MK, Coulibaly B, Adingra GP, Berté D, Ta BTD, Koné M, Traoré BM, Sutherland SA, Crump RE, Huang CI, Madan J, Bessell PR, Barreaux A, Solano P, Crowley EH, Rock KS, Jamonneau V. Towards the sustainable elimination of gambiense human African trypanosomiasis in Côte d'Ivoire using an integrated approach. PLoS Negl Trop Dis 2023; 17:e0011514. [PMID: 37523361 PMCID: PMC10443840 DOI: 10.1371/journal.pntd.0011514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 08/22/2023] [Accepted: 07/07/2023] [Indexed: 08/02/2023] Open
Abstract
BACKGROUND Human African trypanosomiasis is a parasitic disease caused by trypanosomes among which Trypanosoma brucei gambiense is responsible for a chronic form (gHAT) in West and Central Africa. Its elimination as a public health problem (EPHP) was targeted for 2020. Côte d'Ivoire was one of the first countries to be validated by WHO in 2020 and this was particularly challenging as the country still reported around a hundred cases a year in the early 2000s. This article describes the strategies implemented including a mathematical model to evaluate the reporting results and infer progress towards sustainable elimination. METHODS The control methods used combined both exhaustive and targeted medical screening strategies including the follow-up of seropositive subjects- considered as potential asymptomatic carriers to diagnose and treat cases- as well as vector control to reduce the risk of transmission in the most at-risk areas. A mechanistic model was used to estimate the number of underlying infections and the probability of elimination of transmission (EoT) was met between 2000-2021 in two endemic and two hypo-endemic health districts. RESULTS Between 2015 and 2019, nine gHAT cases were detected in the two endemic health districts of Bouaflé and Sinfra in which the number of cases/10,000 inhabitants was far below 1, a necessary condition for validating EPHP. Modelling estimated a slow but steady decline in transmission across the health districts, bolstered in the two endemic health districts by the introduction of vector control. The decrease in underlying transmission in all health districts corresponds to a high probability that EoT has already occurred in Côte d'Ivoire. CONCLUSION This success was achieved through a multi-stakeholder and multidisciplinary one health approach where research has played a major role in adapting tools and strategies to this large epidemiological transition to a very low prevalence. This integrated approach will need to continue to reach the verification of EoT in Côte d'Ivoire targeted by 2025.
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Affiliation(s)
- Dramane Kaba
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Mathurin Koffi
- Laboratoire de Biodiversité et Gestion des Ecosystèmes Tropicaux, Unité de Recherche en Génétique et Epidémiologie Moléculaire, UFR Environnement, Université Jean Lorougnon Guédé, Daloa, Côte d’Ivoire
| | - Lingué Kouakou
- Programme National d’Élimination de la Trypanosomiase Humaine Africaine, Abidjan, Côte d’Ivoire
| | | | - Vincent Djohan
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Fabrice Courtin
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Martial Kassi N’Djetchi
- Laboratoire de Biodiversité et Gestion des Ecosystèmes Tropicaux, Unité de Recherche en Génétique et Epidémiologie Moléculaire, UFR Environnement, Université Jean Lorougnon Guédé, Daloa, Côte d’Ivoire
| | - Bamoro Coulibaly
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Guy Pacôme Adingra
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Djakaridja Berté
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Bi Tra Dieudonné Ta
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Minayégninrin Koné
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
- Laboratoire de Biodiversité et Gestion des Ecosystèmes Tropicaux, Unité de Recherche en Génétique et Epidémiologie Moléculaire, UFR Environnement, Université Jean Lorougnon Guédé, Daloa, Côte d’Ivoire
| | - Barkissa Mélika Traoré
- Laboratoire de Biodiversité et Gestion des Ecosystèmes Tropicaux, Unité de Recherche en Génétique et Epidémiologie Moléculaire, UFR Environnement, Université Jean Lorougnon Guédé, Daloa, Côte d’Ivoire
| | - Samuel A. Sutherland
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Mathematical Sciences Building, The University of Warwick, Coventry, United Kingdom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Ronald E. Crump
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Mathematical Sciences Building, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, Zeeman Building, The University of Warwick, Coventry, United Kingdom
| | - Ching-I Huang
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Mathematical Sciences Building, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, Zeeman Building, The University of Warwick, Coventry, United Kingdom
| | - Jason Madan
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Mathematical Sciences Building, The University of Warwick, Coventry, United Kingdom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | | | - Antoine Barreaux
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Philippe Solano
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
| | - Emily H. Crowley
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Mathematical Sciences Building, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, Zeeman Building, The University of Warwick, Coventry, United Kingdom
| | - Kat S. Rock
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Mathematical Sciences Building, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, Zeeman Building, The University of Warwick, Coventry, United Kingdom
| | - Vincent Jamonneau
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
- Unité Mixte de Recherche IRD-CIRAD 177, INTERTRYP, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, France
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14
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Magang EMK, Kamga RMN, Telleria J, Tichit M, Crouzols A, Kaboré J, Hardy D, Bouaka CUT, Jamonneau V, Rotureau B, Kuete V, Bart JM, Simo G. Prevalence of blood and skin trypanosomes in domestic and wild fauna from two sleeping sickness foci in Southern Cameroon. PLoS Negl Trop Dis 2023; 17:e0011528. [PMID: 37498955 PMCID: PMC10411957 DOI: 10.1371/journal.pntd.0011528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 08/08/2023] [Accepted: 07/12/2023] [Indexed: 07/29/2023] Open
Abstract
Although studies on African Trypanosomiases revealed a variety of trypanosome species in the blood of various animal taxa, animal reservoirs of Trypanosoma brucei gambiense and anatomical niches such as skin have been overlooked in most epidemiological settings. This study aims to update epidemiological data on trypanosome infections in animals from human African trypanosomiasis (HAT) foci of Cameroon. Blood and skin snips were collected from 291 domestic and wild animals. DNA was extracted from blood and skin snips and molecular approaches were used to identify different trypanosomes species. Immunohistochemical analyses were used to confirm trypanosome infections in skin snips. PCR revealed 137 animals (47.1%) with at least one trypanosome species in the blood and/or in the skin. Of these 137 animals, 90 (65.7%) and 32 (23.4%) had trypanosome infections respectively in the blood and skin. Fifteen (10.9%) animals had trypanosome infections in both blood and skin snip. Animals from the Campo HAT focus (55.0%) were significantly (X2 = 17.6; P< 0.0001) more infected than those (29.7%) from Bipindi. Trypanosomes of the subgenus Trypanozoon were present in 27.8% of animals while T. vivax, T. congolense forest type and savannah type were detected in 16.5%, 10.3% and 1.4% of animals respectively. Trypanosoma b. gambiense infections were detected in the blood of 7.6% (22/291) of animals. No T. b. gambiense infection was detected in skin. This study highlights the presence of several trypanosome species in the blood and skin of various wild and domestic animals. Skin appeared as an anatomical reservoir for trypanosomes in animals. Despite methodological limitations, pigs, sheep, goats and wild animals were confirmed as potential reservoirs of T. b. gambiense. These animal reservoirs must be considered for the designing of control strategies that will lead to sustainable elimination of HAT.
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Affiliation(s)
- Eugenie Melaine Kemta Magang
- Molecular Parasitology & Entomology Sub-unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
- Univ. Montpellier, CIRAD, IRD, Intertryp, Montpellier, France
| | - Rolin Mitterran Ndefo Kamga
- Molecular Parasitology & Entomology Sub-unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Jenny Telleria
- Univ. Montpellier, CIRAD, IRD, Intertryp, Montpellier, France
| | - Magali Tichit
- Histopathology Platform, Institut Pasteur, Paris, France
| | - Aline Crouzols
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur Paris, Université Paris Cité, Paris, France
| | - Jacques Kaboré
- Centre International de Recherche-Développement sur l’Elevage en zone Subhumide, Unité de recherche sur les maladies à vecteurs et biodiversité, Bobo-Dioulasso, Burkina Faso
| | - David Hardy
- Histopathology Platform, Institut Pasteur, Paris, France
| | | | - Vincent Jamonneau
- Univ. Montpellier, CIRAD, IRD, Intertryp, Montpellier, France
- Unité de Recherche « Trypanosomoses », Institut Pierre Richet, Bouaké, Côte d’Ivoire
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201, Department of Parasites and Insect Vectors, Institut Pasteur Paris, Université Paris Cité, Paris, France
- Parasitology Unit, Institut Pasteur of Guinea, Conakry, Guinea
| | - Victor Kuete
- Research Unit of Microbiology and Antimicrobial Substances, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | | | - Gustave Simo
- Molecular Parasitology & Entomology Sub-unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
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15
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Nascimento IJDS, Cavalcanti MDAT, de Moura RO. Exploring N-myristoyltransferase as a promising drug target against parasitic neglected tropical diseases. Eur J Med Chem 2023; 258:115550. [PMID: 37336067 DOI: 10.1016/j.ejmech.2023.115550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/04/2023] [Accepted: 06/06/2023] [Indexed: 06/21/2023]
Abstract
Neglected tropical diseases (NTDs) constitute a group of approximately 20 infectious diseases that mainly affect the impoverished population without basic sanitation in tropical countries. These diseases are responsible for many deaths worldwide, costing billions of dollars in public health investment to treat and control these infections. Among them are the diseases caused by protozoa of the Trypanosomatid family, which constitute Trypanosoma cruzi (Chagas disease), Trypanosoma brucei (sleeping sickness), and Leishmaniasis. In addition, there is a classification of other diseases, called the big three, AIDS, tuberculosis, and malaria, which are endemic in countries with tropical conditions. Despite the high mortality rates, there is still a gap in the treatment. The drugs have a high incidence of side effects and protozoan resistance, justifying the investment in developing new alternatives. In fact, the Target-Based Drug Design (TBDD) approach is responsible for identifying several promising compounds, and among the targets explored through this approach, N-myristoyltransferase (NMT) stands out. It is an enzyme related to the co-translational myristoylation of N-terminal glycine in various peptides. The myristoylation process is a co-translation that occurs after removing the initiator methionine. This process regulates the assembly of protein complexes and stability, which justifies its potential as a drug target. In order to propose NMT as a potential target for parasitic diseases, this review will address the entire structure and function of this enzyme and the primary studies demonstrating its promising potential against Leishmaniasis, T. cruzi, T. brucei, and malaria. We hope our information can help researchers worldwide search for potential drugs against these diseases that have been threatening the health of the world's population.
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Affiliation(s)
- Igor José Dos Santos Nascimento
- Postgraduate Program in Pharmaceutical Sciences, State University of Paraíba, Campina Grande, 58429-500, Brazil; Cesmac University Center, Pharmacy Departament, Maceió, Brazil; Drug Development and Synthesis Laboratory, Department of Pharmacy, State University of Paraíba, Campina Grande, 58429-500, Brazil.
| | - Misael de Azevedo Teotônio Cavalcanti
- Postgraduate Program in Pharmaceutical Sciences, State University of Paraíba, Campina Grande, 58429-500, Brazil; Drug Development and Synthesis Laboratory, Department of Pharmacy, State University of Paraíba, Campina Grande, 58429-500, Brazil
| | - Ricardo Olimpio de Moura
- Postgraduate Program in Pharmaceutical Sciences, State University of Paraíba, Campina Grande, 58429-500, Brazil; Drug Development and Synthesis Laboratory, Department of Pharmacy, State University of Paraíba, Campina Grande, 58429-500, Brazil
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Meisner J, Kato A, Lemerani MM, Miaka EM, Ismail AT, Wakefield J, Rowhani-Rahbar A, Pigott D, Mayer JD, Lorton C, Rabinowitz PM. Does a One Health approach to human African trypanosomiasis control hasten elimination? A stochastic compartmental modeling approach. Acta Trop 2023; 240:106804. [PMID: 36682395 PMCID: PMC9992224 DOI: 10.1016/j.actatropica.2022.106804] [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: 10/05/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 01/21/2023]
Abstract
BACKGROUND . In response to large strides in the control of human African trypanosomiasis (HAT), in the early 2000s the WHO set targets for elimination of both the gambiense (gHAT) and rhodesiense (rHAT) forms as a public health (EPHP) problem by 2020, and elimination of gHAT transmisson (EOT) by 2030. While global EPHP targets have been met, and EOT appears within reach, current control strategies may fail to achieve gHAT EOT in the presence of animal reservoirs, the role of which is currently uncertain. Furthermore, rHAT is not targeted for EOT due to the known importance of animal reservoirs for this form. METHODS . To evaluate the utility of a One Health approach to gHAT and rHAT EOT, we built and parameterized a compartmental stochastic model, using the Institute for Disease Modeling's Compartmental Modeling Software, to six HAT epidemics: the national rHAT epidemics in Uganda and Malawi, the national gHAT epidemics in Uganda and South Sudan, and two separate gHAT epidemics in Democratic Republic of Congo distinguished by dominant vector species. In rHAT foci the reservoir animal sub-model was stratified on four species groups, while in gHAT foci domestic swine were assumed to be the only competent reservoir. The modeled time horizon was 2005-2045, with calibration performed using HAT surveillance data and Optuna. Interventions included insecticide and trypanocide treatment of domestic animal reservoirs at varying coverage levels. RESULTS . Validation against HAT surveillance data indicates favorable performance overall, with the possible exception of DRC. EOT was not observed in any modeled scenarios for rHAT, however insecticide treatment consistently performed better than trypanocide treatment in terms of rHAT control. EOT was not observed for gHAT at 0% coverage of domestic reservoirs with trypanocides or insecticides, but was observed by 2030 in all test scenarios; again, insecticides demonstrated superior performance to trypanocides. CONCLUSIONS EOT likely cannot be achieved for rHAT without control of wildlife reservoirs, however insecticide treatment of domestic animals holds promise for improved control. In the presence of domestic animal reservoirs, gHAT EOT may not be achieved under current control strategies.
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Affiliation(s)
- Julianne Meisner
- Department of Global Health, University of Washington, Seattle, WA, USA.
| | | | - Marshall M Lemerani
- Trypanosomiasis Control Programme, Malawi Ministry of Health, Lilongwe, Malawi
| | - Erick M Miaka
- Trypanosomiasis Control Programme, Malawi Ministry of Health, Lilongwe, Malawi
| | - Acaga T Ismail
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, DRC
| | - Jonathan Wakefield
- Department of Statistics, University of Washington, Seattle, WA, USA; Department of Biostatistics, University of Washington, Seattle, WA, USA
| | | | - David Pigott
- Department of Health Metrics Sciences, University of Washington, Seattle, WA, USA
| | - Jonathan D Mayer
- Department of Epidemiology, University of Washington, Seattle, WA, USA; Department of Geography, University of Washington, Seattle, WA, USA
| | | | - Peter M Rabinowitz
- Department of Environmental and Occupational Health Sciences, Seattle, WA, USA
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17
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Huang CI, Crump RE, Crowley EH, Hope A, Bessell PR, Shampa C, Mwamba Miaka E, Rock KS. A modelling assessment of short- and medium-term risks of programme interruptions for gambiense human African trypanosomiasis in the DRC. PLoS Negl Trop Dis 2023; 17:e0011299. [PMID: 37115809 PMCID: PMC10171604 DOI: 10.1371/journal.pntd.0011299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 05/10/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
Gambiense human African trypanosomiasis (gHAT) is a deadly vector-borne, neglected tropical disease found in West and Central Africa targeted for elimination of transmission (EoT) by 2030. The recent pandemic has illustrated how it can be important to quantify the impact that unplanned disruption to programme activities may have in achieving EoT. We used a previously developed model of gHAT fitted to data from the Democratic Republic of the Congo, the country with the highest global case burden, to explore how interruptions to intervention activities, due to e.g. COVID-19, Ebola or political instability, could impact progress towards EoT and gHAT burden. We simulated transmission and reporting dynamics in 38 regions within Kwilu, Mai Ndombe and Kwango provinces under six interruption scenarios lasting for nine or twenty-one months. Included in the interruption scenarios are the cessation of active screening in all scenarios and a reduction in passive detection rates and a delay or suspension of vector control deployments in some scenarios. Our results indicate that, even under the most extreme 21-month interruption scenario, EoT is not predicted to be delayed by more than one additional year compared to the length of the interruption. If existing vector control deployments continue, we predict no delay in achieving EoT even when both active and passive screening activities are interrupted. If passive screening remains as functional as in 2019, we expect a marginal negative impact on transmission, however this depends on the strength of passive screening in each health zone. We predict a pronounced increase in additional gHAT disease burden (morbidity and mortality) in many health zones if both active and passive screening were interrupted compared to the interruption of active screening alone. The ability to continue existing vector control during medical activity interruption is also predicted to avert a moderate proportion of disease burden.
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Affiliation(s)
- Ching-I Huang
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Ronald E. Crump
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Emily H. Crowley
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Andrew Hope
- Liverpool School of Tropical Medicine (LSTM), Liverpool, United Kingdom
| | | | - Chansy Shampa
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Kat S. Rock
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
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18
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Synthesis of urea and thiourea derivatives of C20-epi-aminosalinomycin and their activity against Trypanosoma brucei. Eur J Med Chem 2023; 250:115241. [PMID: 36870272 DOI: 10.1016/j.ejmech.2023.115241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/09/2023] [Accepted: 02/24/2023] [Indexed: 02/27/2023]
Abstract
Salinomycin (SAL) is a natural polyether ionophore that exhibits a very broad spectrum of biological effects, ranging from anticancer to antiparasitic activities. Our recent studies have shown that the chemical modification of the SAL biomolecule is a fruitful strategy for generating lead compounds for the development of novel antitrypanosomal agents. As a continuation of our program to develop trypanocidal active lead structures, we synthesized a series of 14 novel urea and thiourea analogs of C20-epi-aminosalinomycin (compound 2b). The trypanocidal and cytotoxic activities of the derivatives were assessed with the mammalian life cycle stage of Trypanosoma brucei and human leukemic HL-60 cells, respectively. The most antitrypanosomal compounds were the two thiourea derivatives 4b (C20-n-butylthiourea) and 4d (C20-phenylthiourea) with 50% growth inhibition (GI50) values of 0.18 and 0.22 μM and selectivity indices of 47 and 41, respectively. As potent SAL derivatives have been shown to induce strong cell swelling in bloodstream forms of T. brucei, the effect of compounds 4b and 4d to increase the cell volume of the parasite was also investigated. Interestingly, both derivatives were capable to induce faster cell swelling in bloodstream-form trypanosomes than the reference compound SAL. These findings support the suggestion that C20-epi-aminosalinomycin derivatives are suitable leads in the rational development of new and improved trypanocidal drugs.
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19
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Ilboudo K, Hounyeme RE, Kabore J, Boulangé A, Gimonneau G, Salou E, Belem AGM, Lejon V, Compaoré CFA, Bucheton B, Koffi M, Solano P, Berthier D, Thevenon S, Jamonneau V. Experimental evidence that immune trypanolysis using the LiTat 1.3 and LiTat 1.5 variant antigen types is not specific to Trypanosoma brucei gambiense in pigs. Parasite 2022; 29:61. [PMID: 36562442 PMCID: PMC9879134 DOI: 10.1051/parasite/2022063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/04/2022] [Indexed: 12/24/2022] Open
Abstract
In the context of the human African trypanosomiasis elimination process, reliable and accurate diagnostic tools are crucial for exploring the role of a potential animal reservoir of Trypanosoma brucei gambiense. The immune trypanolysis test (TL) using the variant antigen types (VAT) LiTat 1.3 and LiTat 1.5, described as a specific serological method to detect people infected by T. b. gambiense, seems to be a promising tool. However, its specificity was recently questioned during field animal surveys. The present study evaluates the performance of TL during experimental T. b. brucei infection in pigs. Eight infected pigs and four uninfected pigs were followed up with blood and plasma collection. Blood was used for parasitological investigation. TL was performed on the plasma with the LiTat 1.3, LiTat 1.5 and LiTat 1.6 VATs. All control pigs remained negative to parasitological investigation and TL. Trypanosomes were detected in all the infected pigs and the first detection was between 10 and 14 days post infection (dpi). TL results showed that infected pigs developed antibodies against the three VATs. The first antibody detections by TL occurred between 14 and 21 dpi for antibodies directed against LiTat 1.6, 21 and 168 dpi for antibodies directed against LiTat 1.5 and 70, and 182 dpi for antibodies directed against LiTat 1.3. This study highlights for the first time that TL using LiTat 1.3 and LiTat 1.5 VATs is not specific to T. b. gambiense. Development of specific diagnostic tools for the detection of T. b. gambiense infections in animals, especially in pigs, is still needed.
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Affiliation(s)
- Kadidiata Ilboudo
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Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Élevage en Zone Subhumide 01 BP 454 Bobo-Dioulasso 01 Burkina Faso
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Unité de Formation et de Recherche Sciences et Techniques, Université Nazi Boni 01 BP 1091 Bobo-Dioulasso Burkina-Faso
| | - Robert Eustache Hounyeme
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Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Élevage en Zone Subhumide 01 BP 454 Bobo-Dioulasso 01 Burkina Faso
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Unité de Recherche « Trypanosomoses », Institut Pierre Richet 01 BP 1500 Bouaké Côte d’Ivoire
| | - Jacques Kabore
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Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Élevage en Zone Subhumide 01 BP 454 Bobo-Dioulasso 01 Burkina Faso
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Unité de Formation et de Recherche Sciences et Techniques, Université Nazi Boni 01 BP 1091 Bobo-Dioulasso Burkina-Faso
| | - Alain Boulangé
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Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Élevage en Zone Subhumide 01 BP 454 Bobo-Dioulasso 01 Burkina Faso
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Unité de Recherche « Trypanosomoses », Institut Pierre Richet 01 BP 1500 Bouaké Côte d’Ivoire
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Université de Montpellier, CIRAD, IRD, Intertryp F-34398 Montpellier France
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CIRAD, UMR INTERTRYP F-34398 Montpellier France
| | - Geoffrey Gimonneau
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Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Élevage en Zone Subhumide 01 BP 454 Bobo-Dioulasso 01 Burkina Faso
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Université de Montpellier, CIRAD, IRD, Intertryp F-34398 Montpellier France
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Laboratoire National d’Élevage et de Recherches Vétérinaires, Service de Bio-Écologie et Pathologies Parasitaires BP 2057 Dakar – Hann Sénégal
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CIRAD, UMR INTERTRYP F-34398 Montpellier France
| | - Ernest Salou
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Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Élevage en Zone Subhumide 01 BP 454 Bobo-Dioulasso 01 Burkina Faso
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Unité de Formation et de Recherche Sciences et Techniques, Université Nazi Boni 01 BP 1091 Bobo-Dioulasso Burkina-Faso
| | | | - Veerle Lejon
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Université de Montpellier, CIRAD, IRD, Intertryp F-34398 Montpellier France
| | - Charlie Franck Alfred Compaoré
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Unité de Recherche sur les Maladies à Vecteurs et Biodiversité, Centre International de Recherche-Développement sur l’Élevage en Zone Subhumide 01 BP 454 Bobo-Dioulasso 01 Burkina Faso
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Unité de Formation et de Recherche Sciences et Techniques, Université Nazi Boni 01 BP 1091 Bobo-Dioulasso Burkina-Faso
| | - Bruno Bucheton
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Université de Montpellier, CIRAD, IRD, Intertryp F-34398 Montpellier France
| | - Mathurin Koffi
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Laboratoire de Biodiversité et Gestion des Écosystèmes Tropicaux, Unité de Recherche en Génétique et Épidémiologie Moléculaire, UFR Environnement, Université Jean Lorougnon Guédé BP 150 Daloa Côte d’Ivoire
| | - Philippe Solano
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Université de Montpellier, CIRAD, IRD, Intertryp F-34398 Montpellier France
| | - David Berthier
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Université de Montpellier, CIRAD, IRD, Intertryp F-34398 Montpellier France
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CIRAD, UMR INTERTRYP F-34398 Montpellier France
| | - Sophie Thevenon
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Université de Montpellier, CIRAD, IRD, Intertryp F-34398 Montpellier France
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CIRAD, UMR INTERTRYP F-34398 Montpellier France
| | - Vincent Jamonneau
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Unité de Recherche « Trypanosomoses », Institut Pierre Richet 01 BP 1500 Bouaké Côte d’Ivoire
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Université de Montpellier, CIRAD, IRD, Intertryp F-34398 Montpellier France
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20
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VSGs Expressed during Natural T. b. gambiense Infection Exhibit Extensive Sequence Divergence and a Subspecies-Specific Bias towards Type B N-Terminal Domains. mBio 2022; 13:e0255322. [PMID: 36354333 PMCID: PMC9765701 DOI: 10.1128/mbio.02553-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Trypanosoma brucei gambiense is the primary causative agent of human African trypanosomiasis (HAT), a vector-borne disease endemic to West and Central Africa. The extracellular parasite evades antibody recognition within the host bloodstream by altering its variant surface glycoprotein (VSG) coat through a process of antigenic variation. The serological tests that are widely used to screen for HAT use VSG as one of the target antigens. However, the VSGs expressed during human infection have not been characterized. Here, we use VSG sequencing (VSG-seq) to analyze the VSGs expressed in the blood of patients infected with T. b. gambiense and compared them to VSG expression in Trypanosoma brucei rhodesiense infections in humans as well as Trypanosoma brucei brucei infections in mice. The 44 VSGs expressed during T. b. gambiense infection revealed a striking bias toward expression of type B N termini (82% of detected VSGs). This bias is specific to T. b. gambiense, which is unique among T. brucei subspecies in its chronic clinical presentation and anthroponotic nature. The expressed T. b. gambiense VSGs also share very little similarity to sequences from 36 T. b. gambiense whole-genome sequencing data sets, particularly in areas of the VSG protein exposed to host antibodies, suggesting the antigen repertoire is under strong selective pressure to diversify. Overall, this work demonstrates new features of antigenic variation in T. brucei gambiense and highlights the importance of understanding VSG repertoires in nature. IMPORTANCE Human African trypanosomiasis is a neglected tropical disease primarily caused by the extracellular parasite Trypanosoma brucei gambiense. To avoid elimination by the host, these parasites repeatedly replace their variant surface glycoprotein (VSG) coat. Despite the important role of VSGs in prolonging infection, VSG expression during human infections is poorly understood. A better understanding of natural VSG gene expression dynamics can clarify the mechanisms that T. brucei uses to alter its VSG coat. We analyzed the expressed VSGs detected in the blood of patients with trypanosomiasis. Our findings indicate that there are features of antigenic variation unique to human-infective T. brucei subspecies and that natural VSG repertoires may vary more than previously expected.
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21
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Elenga VA, Lissom A, Elion DOA, Vouvoungui JC, Djontu JC, Boumpoutou RK, Ahombo G, Ntoumi F. Risk factors and prevalence of human African trypanosomiasis in individuals living in remote areas of the republic of Congo. BMC Public Health 2022; 22:2322. [PMID: 36510162 PMCID: PMC9743764 DOI: 10.1186/s12889-022-14577-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/09/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Human African trypanosomiasis (HAT) is one of the world's classical neglected tropical diseases representing a major public health threat in sub-Saharan Africa. Although the parasitic disease is in decline in the Republic of Congo, the better understanding of the epidemiological situation of active foci is required to reduce the risk of disease resurgence which could impede progress registered so far. The aim of this study was to determine the prevalence of HAT and the associated risk factors in individuals living in remote areas of the Republic of Congo. METHODS A cross-sectional survey was carried out in volunteers living in rural settings from June 2020 to January 2021. Socio-demographic and Clinical parameters of the participants were recorded. The presence of HAT-specific antibodies was assessed in whole blood, and then confirmed in serial diluted plasma samples using Card-Agglutination Trypanosomiasis Test (CATT)/T.b. gambiense CATT. The Capillary Tube Centrifugation (CTC) and Lymph nodes (LN) examination were done for detecting trypanosome parasites in CATT-serum positive cases. The staging of positive participants was determined by cerebrospinal fluid (CSF) examination. RESULTS Out of 8556 enrolled participants, 48.5% were more than 15 years old, 57.7% were unschooled and 67.2% practiced peasant activities. The prevalence of HAT infection was 0.3% with the predominance of patients at stage 1 of the disease (84.0%). The districts of Mindouli (OR: 25.9 (5.2-468); p = 0.0016) and Mpouya (OR: 13.3 (2.5-246); p = 0.0140) was revealed as the foci of high risk of HAT infection. Several factors were associated with an increased risk of HAT infection mainly including the non-schooling (OR: 5.1 (1.2-21.9); p = 0.0268), the life in couple or married (OR: 3.3 (1.0-11.3); p = 0.0545) and the practice of peasant activities (OR: 6.9 (2.4-29.3); p = 0.0017). CONCLUSION This study highlights the need of revising and strengthening the strategies of HAT control in Republic of Congo, using an approach which will take into account the education level, the marital status and the occupation of the population at risk.
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Affiliation(s)
- Viny Andzi Elenga
- grid.452468.90000 0004 7672 9850Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo ,grid.442828.00000 0001 0943 7362Faculty of Science and Technique, University of Marien Ngouabi, Brazzaville, Republic of Congo
| | - Abel Lissom
- grid.452468.90000 0004 7672 9850Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo ,grid.449799.e0000 0004 4684 0857Department of Biological science, Faculty of Science, University of Bamenda, Bamenda, Cameroon
| | - Darrel Ornelle Assiana Elion
- grid.452468.90000 0004 7672 9850Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo ,grid.442828.00000 0001 0943 7362Faculty of Science and Technique, University of Marien Ngouabi, Brazzaville, Republic of Congo
| | - Jeannhey Christevy Vouvoungui
- grid.452468.90000 0004 7672 9850Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo ,grid.442828.00000 0001 0943 7362Faculty of Science and Technique, University of Marien Ngouabi, Brazzaville, Republic of Congo
| | - Jean Claude Djontu
- grid.452468.90000 0004 7672 9850Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
| | - Reauchelvy Kamal Boumpoutou
- grid.452468.90000 0004 7672 9850Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo
| | - Gabriel Ahombo
- grid.442828.00000 0001 0943 7362Faculty of Science and Technique, University of Marien Ngouabi, Brazzaville, Republic of Congo
| | - Francine Ntoumi
- grid.452468.90000 0004 7672 9850Fondation Congolaise pour la Recherche Médicale, Brazzaville, Republic of Congo ,grid.10392.390000 0001 2190 1447Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
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22
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Ngay Lukusa I, Van Reet N, Mumba Ngoyi D, Mwamba Miaka E, Masumu J, Patient Pyana P, Mutombo W, Ngolo D, Kobo V, Akwaso F, Ilunga M, Kaninda L, Mutanda S, Mpoyi Muamba D, Valverde Mordt O, Tarral A, Rembry S, Büscher P, Lejon V. Trypanosome spliced leader RNA for diagnosis of acoziborole treatment outcome in gambiense human African trypanosomiasis: A longitudinal follow-up study. EBioMedicine 2022; 86:104376. [PMID: 36436279 PMCID: PMC9700268 DOI: 10.1016/j.ebiom.2022.104376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 11/04/2022] [Accepted: 11/07/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Detection of spliced leader (SL)-RNA allows sensitive diagnosis of gambiense human African trypanosomiasis (HAT). We investigated its diagnostic performance for treatment outcome assessment. METHODS Blood and cerebrospinal fluid (CSF) from a consecutive series of 97 HAT patients, originating from the Democratic Republic of the Congo, were prospectively collected before treatment with acoziborole, and during 18 months of longitudinal follow-up after treatment. For treatment outcome assessment, SL-RNA detection was compared with microscopic trypanosome detection and CSF white blood cell count. The trial was registered under NCT03112655 in clinicaltrials.gov. FINDINGS Before treatment, respectively 94.9% (92/97; CI 88.5-97.8%) and 67.7% (65/96; CI 57.8-76.2%) HAT patients were SL-RNA positive in blood or CSF. During follow-up, one patient relapsed with trypanosomes observed at 18 months, and was SL-RNA positive in blood and CSF at 12 months, and CSF positive at 18 months. Among cured patients, one individual tested SL-RNA positive in blood at month 12 (Specificity 98.9%; 90/91; CI 94.0-99.8%) and 18 (Specificity 98.9%; 88/89; CI 93.9-99.8%). INTERPRETATION SL-RNA detection for HAT treatment outcome assessment shows ≥98.9% specificity in blood and 100% in CSF, and may detect relapses without lumbar puncture. FUNDING The DiTECT-HAT project is part of the EDCTP2 programme, supported by Horizon 2020, the European Union Funding for Research and Innovation (grant number DRIA-2014-306-DiTECT-HAT).
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Affiliation(s)
- Ipos Ngay Lukusa
- Department of Parasitology, Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | - Nick Van Reet
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Dieudonné Mumba Ngoyi
- Department of Parasitology, Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Justin Masumu
- Department of Parasitology, Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | - Pati Patient Pyana
- Department of Parasitology, Institut National de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | - Wilfried Mutombo
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Digas Ngolo
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Vincent Kobo
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Felix Akwaso
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Médard Ilunga
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Lewis Kaninda
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Sylvain Mutanda
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | - Dieudonné Mpoyi Muamba
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ministry of Health, Kinshasa, Democratic Republic of the Congo
| | | | - Antoine Tarral
- Drugs for Neglected Diseases Initiative, Geneva, Switzerland
| | - Sandra Rembry
- Drugs for Neglected Diseases Initiative, Geneva, Switzerland
| | - Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Veerle Lejon
- Mixed Research Unit 177 Intertryp, Institut de Recherche pour le Développement, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, University of Montpellier, Montpellier, France.
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Periferakis A, Periferakis K, Badarau IA, Petran EM, Popa DC, Caruntu A, Costache RS, Scheau C, Caruntu C, Costache DO. Kaempferol: Antimicrobial Properties, Sources, Clinical, and Traditional Applications. Int J Mol Sci 2022; 23:ijms232315054. [PMID: 36499380 PMCID: PMC9740324 DOI: 10.3390/ijms232315054] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/23/2022] [Accepted: 11/26/2022] [Indexed: 12/03/2022] Open
Abstract
Flavonoids are a category of plant-derived compounds which exhibit a large number of health-related effects. One of the most well-known and studied flavonoids is kaempferol, which can be found in a wide variety of herbs and plant families. Apart from their anticarcinogenic and anti-inflammatory effects, kaempferol and its associated compounds also exhibit antibacterial, antifungal, and antiprotozoal activities. The development of drugs and treatment schemes based on these compounds is becoming increasingly important in the face of emerging resistance of numerous pathogens as well as complex molecular interactions between various drug therapies. In addition, many of the kaempferol-containing plants are used in traditional systems all over the world for centuries to treat numerous conditions. Due to its variety of sources and associated compounds, some molecular mechanisms of kaempferol antimicrobial activity are well known while others are still under analysis. This paper thoroughly documents the vegetal and food sources of kaempferol as well as the most recent and significant studies regarding its antimicrobial applications.
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Affiliation(s)
- Argyrios Periferakis
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Akadimia of Ancient Greek and Traditional Chinese Medicine, 16675 Athens, Greece
| | - Konstantinos Periferakis
- Akadimia of Ancient Greek and Traditional Chinese Medicine, 16675 Athens, Greece
- Pan-Hellenic Organization of Educational Programs (P.O.E.P), 17236 Athens, Greece
- Orasis Acupuncture Institute, 11526 Athens, Greece
| | - Ioana Anca Badarau
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Elena Madalina Petran
- Department of Biochemistry, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Toxicology, Grigore Alexandrescu Emergency Children’s Hospital, 011743 Bucharest, Romania
| | - Delia Codruta Popa
- Department of Biochemistry, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Hematology, Fundeni Clinical Institute, 022328 Bucharest, Romania
- Correspondence: (D.C.P.); (C.S.)
| | - Ana Caruntu
- Department of Oral and Maxillofacial Surgery, ‘Dr. Carol Davila’ Central Military Emergency Hospital, 010825 Bucharest, Romania
- Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine, ‘Titu Maiorescu’ University, 031593 Bucharest, Romania
| | - Raluca Simona Costache
- Department of Gastroenterology, Gastroenterology and Internal Medicine Clinic, ‘Dr. Carol Davila’ Central Military Emergency Hospital, 010825 Bucharest, Romania
- Department of Internal Medicine and Gastroenterology, ‘Carol Davila’ University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Cristian Scheau
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Correspondence: (D.C.P.); (C.S.)
| | - Constantin Caruntu
- Department of Physiology, The “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Department of Dermatology, ‘Prof. N.C. Paulescu’ National Institute of Diabetes, Nutrition and Metabolic Diseases, 011233 Bucharest, Romania
| | - Daniel Octavian Costache
- Department of Dermatology, ‘Dr. Carol Davila’ Central Military Emergency Hospital, 010825 Bucharest, Romania
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Mabille D, Dirkx L, Thys S, Vermeersch M, Montenye D, Govaerts M, Hendrickx S, Takac P, Van Weyenbergh J, Pintelon I, Delputte P, Maes L, Pérez-Morga D, Timmermans JP, Caljon G. Impact of pulmonary African trypanosomes on the immunology and function of the lung. Nat Commun 2022; 13:7083. [PMID: 36400767 PMCID: PMC9674601 DOI: 10.1038/s41467-022-34757-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 11/04/2022] [Indexed: 11/19/2022] Open
Abstract
Approximately 20% of sleeping sickness patients exhibit respiratory complications, however, with a largely unknown role of the parasite. Here we show that tsetse fly-transmitted Trypanosoma brucei parasites rapidly and permanently colonize the lungs and occupy the extravascular spaces surrounding the blood vessels of the alveoli and bronchi. They are present as nests of multiplying parasites exhibiting close interactions with collagen and active secretion of extracellular vesicles. The local immune response shows a substantial increase of monocytes, macrophages, dendritic cells and γδ and activated αβ T cells and a later influx of neutrophils. Interestingly, parasite presence results in a significant reduction of B cells, eosinophils and natural killer cells. T. brucei infected mice show no infection-associated pulmonary dysfunction, mirroring the limited pulmonary clinical complications during sleeping sickness. However, the substantial reduction of the various immune cells may render individuals more susceptible to opportunistic infections, as evident by a co-infection experiment with respiratory syncytial virus. Collectively, these observations provide insights into a largely overlooked target organ, and may trigger new diagnostic and supportive therapeutic approaches for sleeping sickness.
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Affiliation(s)
- Dorien Mabille
- Laboratory of Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Wilrijk, Belgium
| | - Laura Dirkx
- Laboratory of Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Wilrijk, Belgium
| | - Sofie Thys
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Wilrijk, Belgium
| | - Marjorie Vermeersch
- Center for Microscopy and Molecular Imaging, Université libre de Bruxelles, Gosselies, Belgium
- Laboratory of Molecular Parasitology, IBMM, Université libre de Bruxelles, Gosselies, Belgium
| | - Daniel Montenye
- Center for Microscopy and Molecular Imaging, Université libre de Bruxelles, Gosselies, Belgium
- Laboratory of Molecular Parasitology, IBMM, Université libre de Bruxelles, Gosselies, Belgium
| | - Matthias Govaerts
- Laboratory of Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Wilrijk, Belgium
| | - Sarah Hendrickx
- Laboratory of Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Wilrijk, Belgium
| | - Peter Takac
- Institute of Zoology, Slovak Academy of Sciences, 84506, Bratislava, Slovakia
- Scientica, Ltd., 83106, Bratislava, Slovakia
| | - Johan Van Weyenbergh
- Clinical and Epidemiological Virology, Department of Microbiology, Immunology and Transplantation, Rega Institute of Medical Research, KU Leuven, Leuven, Belgium
| | - Isabel Pintelon
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Wilrijk, Belgium
| | - Peter Delputte
- Laboratory of Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Wilrijk, Belgium
| | - Louis Maes
- Laboratory of Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Wilrijk, Belgium
| | - David Pérez-Morga
- Center for Microscopy and Molecular Imaging, Université libre de Bruxelles, Gosselies, Belgium
- Laboratory of Molecular Parasitology, IBMM, Université libre de Bruxelles, Gosselies, Belgium
| | - Jean-Pierre Timmermans
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, Wilrijk, Belgium
| | - Guy Caljon
- Laboratory of Microbiology, Parasitology and Hygiene, Infla-Med Centre of Excellence, University of Antwerp, Wilrijk, Belgium.
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Heme-deficient metabolism and impaired cellular differentiation as an evolutionary trade-off for human infectivity in Trypanosoma brucei gambiense. Nat Commun 2022; 13:7075. [PMID: 36400774 PMCID: PMC9674590 DOI: 10.1038/s41467-022-34501-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/27/2022] [Indexed: 11/19/2022] Open
Abstract
Resistance to African trypanosomes in humans relies in part on the high affinity targeting of a trypanosome lytic factor 1 (TLF1) to a trypanosome haptoglobin-hemoglobin receptor (HpHbR). While TLF1 avoidance by the inactivation of HpHbR contributes to Trypanosoma brucei gambiense human infectivity, the evolutionary trade-off of this adaptation is unknown, as the physiological function of the receptor remains to be elucidated. Here we show that uptake of hemoglobin via HpHbR constitutes the sole heme import pathway in the trypanosome bloodstream stage. T. b. gambiense strains carrying the inactivating mutation in HpHbR, as well as genetically engineered T. b. brucei HpHbR knock-out lines show only trace levels of intracellular heme and lack hemoprotein-based enzymatic activities, thereby providing an uncommon example of aerobic parasitic proliferation in the absence of heme. We further show that HpHbR facilitates the developmental progression from proliferating long slender forms to cell cycle-arrested stumpy forms in T. b. brucei. Accordingly, T. b. gambiense was found to be poorly competent for slender-to-stumpy differentiation unless a functional HpHbR receptor derived from T. b. brucei was genetically restored. Altogether, we identify heme-deficient metabolism and disrupted cellular differentiation as two distinct HpHbR-dependent evolutionary trade-offs for T. b. gambiense human infectivity.
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Franco JR, Cecchi G, Priotto G, Paone M, Kadima Ebeja A, Simarro PP, Diarra A, Sankara D, Zhao W, Dagne DA. Human African trypanosomiasis cases diagnosed in non-endemic countries (2011-2020). PLoS Negl Trop Dis 2022; 16:e0010885. [PMID: 36342910 PMCID: PMC9639846 DOI: 10.1371/journal.pntd.0010885] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/27/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Sleeping sickness, or human African trypanosomiasis (HAT), is transmitted by tsetse flies in endemic foci in sub-Saharan Africa. Because of international travel and population movements, cases are also occasionally diagnosed in non-endemic countries. METHODOLOGY/PRINCIPAL FINDINGS Antitrypanosomal medicines to treat the disease are available gratis through the World Health Organization (WHO) thanks to a public-private partnership, and exclusive distribution of the majority of them enables WHO to gather information on all exported cases. Data collected by WHO are complemented by case reports and scientific publications. During 2011-2020, 49 cases of HAT were diagnosed in 16 non-endemic countries across five continents: 35 cases were caused by Trypanosoma brucei rhodesiense, mainly in tourists visiting wildlife areas in eastern and southern Africa, and 14 cases were due to T. b. gambiense, mainly in African migrants originating from or visiting endemic areas in western and central Africa. CONCLUSIONS/SIGNIFICANCE HAT diagnosis in non-endemic countries is rare and can be challenging, but alertness and surveillance must be maintained to contribute to WHO's elimination goals. Early detection is particularly important as it considerably improves the prognosis.
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Affiliation(s)
- Jose R. Franco
- World Health Organization, Control of Neglected Tropical Diseases, Prevention, Treatment and Care, Geneva, Switzerland
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Gerardo Priotto
- World Health Organization, Control of Neglected Tropical Diseases, Prevention, Treatment and Care, Geneva, Switzerland
| | - Massimo Paone
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | | | | | - Abdoulaye Diarra
- World Health Organization, Regional Office for Africa, Brazzaville, Congo
| | - Dieudonné Sankara
- World Health Organization, Control of Neglected Tropical Diseases, Prevention, Treatment and Care, Geneva, Switzerland
| | - Weining Zhao
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Daniel Argaw Dagne
- World Health Organization, Control of Neglected Tropical Diseases, Prevention, Treatment and Care, Geneva, Switzerland
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27
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Geerts M, Chen Z, Bebronne N, Savill NJ, Schnaufer A, Büscher P, Van Reet N, Van den Broeck F. Deep kinetoplast genome analyses result in a novel molecular assay for detecting Trypanosoma brucei gambiense-specific minicircles. NAR Genom Bioinform 2022; 4:lqac081. [PMID: 36285287 PMCID: PMC9582789 DOI: 10.1093/nargab/lqac081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 09/28/2022] [Accepted: 10/06/2022] [Indexed: 11/14/2022] Open
Abstract
The World Health Organization targeted Trypanosoma brucei gambiense (Tbg) human African trypanosomiasis for elimination of transmission by 2030. Sensitive molecular markers that specifically detect Tbg type 1 (Tbg1) parasites will be important tools to assist in reaching this goal. We aim at improving molecular diagnosis of Tbg1 infections by targeting the abundant mitochondrial minicircles within the kinetoplast of these parasites. Using Next-Generation Sequencing of total cellular DNA extracts, we assembled and annotated the kinetoplast genome and investigated minicircle sequence diversity in 38 animal- and human-infective trypanosome strains. Computational analyses recognized a total of 241 Minicircle Sequence Classes as Tbg1-specific, of which three were shared by the 18 studied Tbg1 strains. We developed a minicircle-based assay that is applicable on animals and as specific as the TgsGP-based assay, the current golden standard for molecular detection of Tbg1. The median copy number of the targeted minicircle was equal to eight, suggesting our minicircle-based assay may be used for the sensitive detection of Tbg1 parasites. Annotation of the targeted minicircle sequence indicated that it encodes genes essential for the survival of the parasite and will thus likely be preserved in natural Tbg1 populations, the latter ensuring the reliability of our novel diagnostic assay.
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Affiliation(s)
- Manon Geerts
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium
| | - Zihao Chen
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Nicolas Bebronne
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium
| | - Nicholas J Savill
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium
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Abstract
PURPOSE OF REVIEW Gambiense human African trypanosomiasis (gHAT), a disease that has killed hundreds of thousands as recently as the 1990s, could be on the verge of elimination or even eradication. This review describes recent developments that give us reasons for optimism as well as some caveats. RECENT FINDINGS New developments in diagnostic and vector control tools, and especially in treatment, make it possible to strive for elimination of transmission of gHAT by 2030, perhaps even eradication. SUMMARY Gambiense human African trypanosomiasis is a deadly infectious disease affecting West and Central Africa, South Sudan and Uganda, and transmitted between humans by tsetse flies. The disease has caused several major epidemics, the latest one in the 1990s. Thanks to recent innovations such as rapid diagnostic tests for population screening, a single-dose oral treatment and a highly efficient vector control strategy, interruption of transmission of the causative parasite is now within reach. If indeed gHAT has an exclusively human reservoir, this could even result in eradication of the disease. Even if there were an animal reservoir, on the basis of epidemiological data, it plays a limited role. Maintaining adequate postelimination surveillance in known historic foci, using the newly developed tools, should be sufficient to prevent any future resurgence.
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Somda MB, N'Djetchi MK, Kaboré J, Ilboudo H, Dama E, Boma S, Courtin F, Poinsignon A, Bengaly Z, Remoué F, Belem AMG, Bucheton B, Jamonneau V, Koffi M. Evaluation of antibody responses to tsetse fly saliva in domestic animals in the sleeping sickness endemic foci of Bonon and Sinfra, Côte d'Ivoire. Vet Parasitol Reg Stud Reports 2022; 34:100773. [PMID: 36041808 DOI: 10.1016/j.vprsr.2022.100773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 07/19/2022] [Accepted: 08/01/2022] [Indexed: 06/15/2023]
Abstract
After intensive control efforts, human African trypanosomiasis (HAT) was declared eliminated in Côte d'Ivoire as a public health problem in December 2020 and the current objective is to achieve the interruption of the transmission (zero cases). Reaching this objective could be hindered by the existence of an animal reservoir of Trypanosoma (T.) brucei (b.) gambiense. In the framework of a study led in 2013 to assess the role of domestic animals in the epidemiology of HAT in the two last active foci from Côte d'Ivoire (Bonon and Sinfra), plasmas were sampled from four species of domestic animals for parasitological (microscopic examination by the buffy coat technique (BCT)), serological (immune trypanolysis (TL)) and molecular (specific PCR: TBR for T. brucei s.l., TCF for T. congolense forest type, TVW for T. vivax and PCR for T. b. gambiense) testing. In order to improve the understanding of the involvement/role of these animals in the transmission of T. b. gambiense, we have quantified in this study the IgG response to whole saliva extracts of Glossina palpalis gambiensis in order to perform an association analysis between anti-saliva responses and the positivity of diagnostic tests. Cattle and pigs had significantly higher rates of anti-tsetse saliva responses compared to goats and sheep (p < 0.01). In addition, the anti-tsetse saliva responses were strongly associated with the parasitology (BCT+), serology (TL+) and PCR (TBR+ and TCF+) results (p < 0.001). These associations indicate a high level of contacts between the positive/infected animals and tsetse flies. Our findings suggest that protecting cattle and pigs against tsetse bites could have a significant impact in reducing transmission of both animal and human trypanosome species, and advocates for a "One health" approach to better control African trypanosomosis in Côte d'Ivoire.
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Affiliation(s)
- Martin Bienvenu Somda
- Université Nazi BONI (UNB), Laboratoire de santé animale tropicale (LASANTROP), 01 BP 1 091 Bobo-Dioulasso 01, Burkina Faso; Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Unité de Recherche «maladies à vecteurs et biodiversité (UMaVeB)», 01 BP 454 Bobo-Dioulasso 01, Burkina Faso.
| | - Martial Kassi N'Djetchi
- Université Jean Lorougnon Guédé (UJLoG), Unité de Formation et de Recherche Environnement, Laboratoire des Interactions Hôte-Microorganisme-Environnement et Evolution, BP 150 Daloa, Côte d'Ivoire
| | - Jacques Kaboré
- Université Nazi BONI (UNB), Laboratoire de santé animale tropicale (LASANTROP), 01 BP 1 091 Bobo-Dioulasso 01, Burkina Faso; Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Unité de Recherche «maladies à vecteurs et biodiversité (UMaVeB)», 01 BP 454 Bobo-Dioulasso 01, Burkina Faso
| | - Hamidou Ilboudo
- Institut de Recherche en Sciences de la Santé (IRSS), Unité de Recherche Clinique de Nanoro (URCN), 11 BP 218 Ouagadougou CMS 11, Burkina Faso
| | - Emilie Dama
- Université Nazi BONI (UNB), Laboratoire de santé animale tropicale (LASANTROP), 01 BP 1 091 Bobo-Dioulasso 01, Burkina Faso
| | - Soudah Boma
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Unité de Recherche «maladies à vecteurs et biodiversité (UMaVeB)», 01 BP 454 Bobo-Dioulasso 01, Burkina Faso
| | - Fabrice Courtin
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Unité Mixte de Recherche 177 INTERTRYP IRD-CIRAD, 34398 Montpellier, France
| | - Anne Poinsignon
- MIVEGEC (Maladies Infectieuses et Vecteurs : Écologie, Génétique, Évolution et Contrôle), University of Montpellier, IRD, CNRS, Montpellier, France
| | - Zakaria Bengaly
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Unité de Recherche «maladies à vecteurs et biodiversité (UMaVeB)», 01 BP 454 Bobo-Dioulasso 01, Burkina Faso
| | - Franck Remoué
- MIVEGEC (Maladies Infectieuses et Vecteurs : Écologie, Génétique, Évolution et Contrôle), University of Montpellier, IRD, CNRS, Montpellier, France
| | - Adrien Marie Gaston Belem
- Université Nazi BONI (UNB), Laboratoire de santé animale tropicale (LASANTROP), 01 BP 1 091 Bobo-Dioulasso 01, Burkina Faso
| | - Bruno Bucheton
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Unité Mixte de Recherche 177 INTERTRYP IRD-CIRAD, 34398 Montpellier, France
| | - Vincent Jamonneau
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Unité Mixte de Recherche 177 INTERTRYP IRD-CIRAD, 34398 Montpellier, France
| | - Mathurin Koffi
- Institut de Recherche en Sciences de la Santé (IRSS), Unité de Recherche Clinique de Nanoro (URCN), 11 BP 218 Ouagadougou CMS 11, Burkina Faso
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Boundenga L, Mombo IM, Augustin MO, Barthélémy N, Nzassi PM, Moukodoum ND, Rougeron V, Prugnolle F. Molecular Identification of Trypanosome Diversity in Domestic Animals Reveals the Presence of Trypanosoma brucei gambiense in Historical Foci of Human African Trypanosomiasis in Gabon. Pathogens 2022; 11:pathogens11090992. [PMID: 36145424 PMCID: PMC9502807 DOI: 10.3390/pathogens11090992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/21/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Human African Trypanosomiasis (HAT) is an infectious disease caused by protozoan parasites belonging to the Trypanosoma genus. In sub-Saharan Africa, there is a significant threat as many people are at risk of infection. Despite this, HAT is classified as a neglected tropical disease. Over the last few years, several studies have reported the existence of a wide diversity of trypanosome species circulating in African animals. Thus, domestic and wild animals could be reservoirs of potentially dangerous trypanosomes for human populations. However, very little is known about the role of domestic animals in maintaining the transmission cycle of human trypanosomes in central Africa, especially in Gabon, where serious cases of infection are recorded each year, sometimes leading to hospitalization or death of patients. Komo-Mondah, located within Estuaries (Gabonese province), stays the most active HAT disease focus in Gabon, with a mean of 20 cases per year. In this study, we evaluated the diversity and prevalence of trypanosomes circulating in domestic animals using the Polymerase Chain Reaction (PCR) technique. We found that 19.34% (53/274) of the domestic animals we studied were infected with trypanosomes. The infection rates varied among taxa, with 23.21% (13/56) of dogs, 16.10% (19/118) of goats, and 21.00% (21/100) of sheep infected. In addition, we have observed a global mixed rate of infections of 20.75% (11/53) among infected individuals. Molecular analyses revealed that at least six Trypanosome species circulate in domestic animals in Gabon (T. congolense, T. simiae, T. simiae Tsavo, T. theileri, T. vivax, T. brucei (including T. brucei brucei, and T. brucei gambiense)). In conclusion, our study showed that domestic animals constitute important potential reservoirs for trypanosome parasites, including T. brucei gambiense, which is responsible for HAT.
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Affiliation(s)
- Larson Boundenga
- International Centre for Medical Research in Franceville (CIRMF), Franceville BP 769, Gabon
- Department of Anthropology, Durham University, South Road, Durham DH1 3LE, UK
- Correspondence: ; Tel.: +241-62521281
| | - Illich Manfred Mombo
- International Centre for Medical Research in Franceville (CIRMF), Franceville BP 769, Gabon
| | | | - Ngoubangoye Barthélémy
- International Centre for Medical Research in Franceville (CIRMF), Franceville BP 769, Gabon
- Department of Anthropology, Durham University, South Road, Durham DH1 3LE, UK
| | - Patrice Makouloutou Nzassi
- International Centre for Medical Research in Franceville (CIRMF), Franceville BP 769, Gabon
- Department of Animal Biology and Ecology, Tropical Ecology Research Institute (IRET-CENAREST), Libreville BP 13354, Gabon
| | - Nancy D. Moukodoum
- International Centre for Medical Research in Franceville (CIRMF), Franceville BP 769, Gabon
| | - Virginie Rougeron
- REHABS, International Research Laboratory, CNRS-NMU-UCBL, George Campus, Nelson Mandela University, George 6529, South Africa
| | - Franck Prugnolle
- REHABS, International Research Laboratory, CNRS-NMU-UCBL, George Campus, Nelson Mandela University, George 6529, South Africa
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31
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Boulangé A, Lejon V, Berthier D, Thévenon S, Gimonneau G, Desquesnes M, Abah S, Agboho P, Chilongo K, Gebre T, Fall AG, Kaba D, Magez S, Masiga D, Matovu E, Moukhtar A, Neves L, Olet PA, Pagabeleguem S, Shereni W, Sorli B, Taioe MO, Tejedor Junco MT, Yagi R, Solano P, Cecchi G. The COMBAT project: controlling and progressively minimizing the burden of vector-borne animal trypanosomosis in Africa. OPEN RESEARCH EUROPE 2022; 2:67. [PMID: 37645305 PMCID: PMC10445831 DOI: 10.12688/openreseurope.14759.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/02/2022] [Indexed: 11/23/2023]
Abstract
Vector-borne diseases affecting livestock have serious impacts in Africa. Trypanosomosis is caused by parasites transmitted by tsetse flies and other blood-sucking Diptera. The animal form of the disease is a scourge for African livestock keepers, is already present in Latin America and Asia, and has the potential to spread further. A human form of the disease also exists, known as human African trypanosomosis or sleeping sickness. Controlling and progressively minimizing the burden of animal trypanosomosis (COMBAT) is a four-year research and innovation project funded by the European Commission, whose ultimate goal is to reduce the burden of animal trypanosomosis (AT) in Africa. The project builds on the progressive control pathway (PCP), a risk-based, step-wise approach to disease reduction or elimination. COMBAT will strengthen AT control and prevention by improving basic knowledge of AT, developing innovative control tools, reinforcing surveillance, rationalizing control strategies, building capacity, and raising awareness. Knowledge gaps on disease epidemiology, vector ecology and competence, and biological aspects of trypanotolerant livestock will be addressed. Environmentally friendly vector control technologies and more effective and adapted diagnostic tools will be developed. Surveillance will be enhanced by developing information systems, strengthening reporting, and mapping and modelling disease risk in Africa and beyond. The socio-economic burden of AT will be assessed at a range of geographical scales. Guidelines for the PCP and harmonized national control strategies and roadmaps will be developed. Gender equality and ethics will be pivotal in all project activities. The COMBAT project benefits from the expertise of African and European research institutions, national veterinary authorities, and international organizations. The project consortium comprises 21 participants, including a geographically balanced representation from 13 African countries, and it will engage a larger number of AT-affected countries through regional initiatives.
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Affiliation(s)
- Alain Boulangé
- CIRAD, UMR INTERTRYP, Bouaké, 01 BP 1500, Cote d'Ivoire
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
| | - Veerle Lejon
- CIRAD, IRD, UMR INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
| | - David Berthier
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
- CIRAD, UMR INTERTRYP, Montpellier, F-34398, France
| | - Sophie Thévenon
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
- CIRAD, UMR INTERTRYP, Montpellier, F-34398, France
| | - Geoffrey Gimonneau
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
- CIRAD, UMR INTERTRYP, Dakar-Hann, BP 2057, Senegal
| | - Marc Desquesnes
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
- CIRAD, UMR INTERTRYP, Toulouse, F-31076, France
| | - Samuel Abah
- Mission Spéciale D'Eradication des Glossines (MSEG), Ministère de l'Elevage, des Pêches et des Industries Animales, Ngaoundéré, BP 263, Cameroon
| | - Prudenciène Agboho
- Centre International de Recherche-Développement sur l’Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, 01 BP 454, Burkina Faso
| | - Kalinga Chilongo
- Tsetse and Trypanosomosis Control Unit (TTCU), Ministry of Fisheries and Livestock, P.O Box 50197, Lusaka, 10101, Zambia
| | - Tsegaye Gebre
- National Institute for Control and Eradication of Tsetse and Trypanosomosis (NICETT), P.O Box 19917, Addis Ababa, Ethiopia
| | - Assane Gueye Fall
- Institut Sénégalais de Recherches Agricoles (ISRA), Dakar-Hann, BP 2057, Senegal
| | - Dramane Kaba
- Institut Pierre Richet (IPR), Institut National de Santé Publique, Bouaké, 01 BP 1500, Cote d'Ivoire
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, B-1050, Belgium
| | - Daniel Masiga
- International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, 00100, Kenya
| | | | - Aldjibert Moukhtar
- Institut de Recherche en Elevage pour le Développement (IRED), N'Djamena, Route de Farcha, BP 433, Chad
| | - Luis Neves
- Centro de Biotecnologia, Universidade Eduardo Mondlane, Maputo, 00200, Mozambique
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Sciences, University of Pretoria, Onderstepoort, 0110, South Africa
| | - Pamela A. Olet
- Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC), Nairobi, 00800, Kenya
| | - Soumaïla Pagabeleguem
- Insectarium de Bobo-Dioulasso – Campagne d'Eradication de la mouche Tsé-tsé et de la Trypanosomose (IBD-CETT), Ministère des ressources animales et halieutiques, Bobo-Dioulasso, 01 BP 1087, Burkina Faso
| | - William Shereni
- Division of Tsetse Control Services (TCD), Ministry of Lands, Agriculture, Fisheries, Water and Rural Development, P.O Box CY52, Harare, Zimbabwe
| | - Brice Sorli
- Institut d'Electronique et des Systèmes (IES), Université de Montpellier, Montpellier, F-34090, France
| | - Moeti O. Taioe
- Onderstepoort Veterinary Research, Agricultural Research Council (ARC), Pretoria, 0110, South Africa
| | | | - Rehab Yagi
- Central Veterinary Research Laboratory (CVRL), Animal Resources Research Corporation, Khartoum, 12217, Sudan
| | - Philippe Solano
- CIRAD, IRD, UMR INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
| | - Giuliano Cecchi
- Animal Production and Health Division, Food and Agriculture Organization of the United Nations (FAO), Rome, 00153, Italy
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Boulangé A, Lejon V, Berthier D, Thévenon S, Gimonneau G, Desquesnes M, Abah S, Agboho P, Chilongo K, Gebre T, Fall AG, Kaba D, Magez S, Masiga D, Matovu E, Moukhtar A, Neves L, Olet PA, Pagabeleguem S, Shereni W, Sorli B, Taioe MO, Tejedor Junco MT, Yagi R, Solano P, Cecchi G. The COMBAT project: controlling and progressively minimizing the burden of vector-borne animal trypanosomosis in Africa. OPEN RESEARCH EUROPE 2022; 2:67. [PMID: 37645305 PMCID: PMC10445831 DOI: 10.12688/openreseurope.14759.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/02/2022] [Indexed: 08/31/2023]
Abstract
Vector-borne diseases affecting livestock have serious impacts in Africa. Trypanosomosis is caused by parasites transmitted by tsetse flies and other blood-sucking Diptera. The animal form of the disease is a scourge for African livestock keepers, is already present in Latin America and Asia, and has the potential to spread further. A human form of the disease also exists, known as human African trypanosomosis or sleeping sickness. Controlling and progressively minimizing the burden of animal trypanosomosis (COMBAT) is a four-year research and innovation project funded by the European Commission, whose ultimate goal is to reduce the burden of animal trypanosomosis (AT) in Africa. The project builds on the progressive control pathway (PCP), a risk-based, step-wise approach to disease reduction or elimination. COMBAT will strengthen AT control and prevention by improving basic knowledge of AT, developing innovative control tools, reinforcing surveillance, rationalizing control strategies, building capacity, and raising awareness. Knowledge gaps on disease epidemiology, vector ecology and competence, and biological aspects of trypanotolerant livestock will be addressed. Environmentally friendly vector control technologies and more effective and adapted diagnostic tools will be developed. Surveillance will be enhanced by developing information systems, strengthening reporting, and mapping and modelling disease risk in Africa and beyond. The socio-economic burden of AT will be assessed at a range of geographical scales. Guidelines for the PCP and harmonized national control strategies and roadmaps will be developed. Gender equality and ethics will be pivotal in all project activities. The COMBAT project benefits from the expertise of African and European research institutions, national veterinary authorities, and international organizations. The project consortium comprises 21 participants, including a geographically balanced representation from 13 African countries, and it will engage a larger number of AT-affected countries through regional initiatives.
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Affiliation(s)
- Alain Boulangé
- CIRAD, UMR INTERTRYP, Bouaké, 01 BP 1500, Cote d'Ivoire
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
| | - Veerle Lejon
- CIRAD, IRD, UMR INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
| | - David Berthier
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
- CIRAD, UMR INTERTRYP, Montpellier, F-34398, France
| | - Sophie Thévenon
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
- CIRAD, UMR INTERTRYP, Montpellier, F-34398, France
| | - Geoffrey Gimonneau
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
- CIRAD, UMR INTERTRYP, Dakar-Hann, BP 2057, Senegal
| | - Marc Desquesnes
- CIRAD, IRD, INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
- CIRAD, UMR INTERTRYP, Toulouse, F-31076, France
| | - Samuel Abah
- Mission Spéciale D'Eradication des Glossines (MSEG), Ministère de l'Elevage, des Pêches et des Industries Animales, Ngaoundéré, BP 263, Cameroon
| | - Prudenciène Agboho
- Centre International de Recherche-Développement sur l’Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, 01 BP 454, Burkina Faso
| | - Kalinga Chilongo
- Tsetse and Trypanosomosis Control Unit (TTCU), Ministry of Fisheries and Livestock, P.O Box 50197, Lusaka, 10101, Zambia
| | - Tsegaye Gebre
- National Institute for Control and Eradication of Tsetse and Trypanosomosis (NICETT), P.O Box 19917, Addis Ababa, Ethiopia
| | - Assane Gueye Fall
- Institut Sénégalais de Recherches Agricoles (ISRA), Dakar-Hann, BP 2057, Senegal
| | - Dramane Kaba
- Institut Pierre Richet (IPR), Institut National de Santé Publique, Bouaké, 01 BP 1500, Cote d'Ivoire
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, B-1050, Belgium
| | - Daniel Masiga
- International Centre of Insect Physiology and Ecology (ICIPE), Nairobi, 00100, Kenya
| | | | - Aldjibert Moukhtar
- Institut de Recherche en Elevage pour le Développement (IRED), N'Djamena, Route de Farcha, BP 433, Chad
| | - Luis Neves
- Centro de Biotecnologia, Universidade Eduardo Mondlane, Maputo, 00200, Mozambique
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Sciences, University of Pretoria, Onderstepoort, 0110, South Africa
| | - Pamela A. Olet
- Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC), Nairobi, 00800, Kenya
| | - Soumaïla Pagabeleguem
- Insectarium de Bobo-Dioulasso – Campagne d'Eradication de la mouche Tsé-tsé et de la Trypanosomose (IBD-CETT), Ministère des ressources animales et halieutiques, Bobo-Dioulasso, 01 BP 1087, Burkina Faso
| | - William Shereni
- Division of Tsetse Control Services (TCD), Ministry of Lands, Agriculture, Fisheries, Water and Rural Development, P.O Box CY52, Harare, Zimbabwe
| | - Brice Sorli
- Institut d'Electronique et des Systèmes (IES), Université de Montpellier, Montpellier, F-34090, France
| | - Moeti O. Taioe
- Onderstepoort Veterinary Research, Agricultural Research Council (ARC), Pretoria, 0110, South Africa
| | | | - Rehab Yagi
- Central Veterinary Research Laboratory (CVRL), Animal Resources Research Corporation, Khartoum, 12217, Sudan
| | - Philippe Solano
- CIRAD, IRD, UMR INTERTRYP, Univ of Montpellier, Montpellier, F-34398, France
| | - Giuliano Cecchi
- Animal Production and Health Division, Food and Agriculture Organization of the United Nations (FAO), Rome, 00153, Italy
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Meisner J, Kato A, Lemerani MM, Mwamba Miaka E, Ismail Taban A, Wakefield J, Rowhani-Rahbar A, Pigott DM, Mayer JD, Rabinowitz PM. The effect of livestock density on Trypanosoma brucei gambiense and T. b. rhodesiense: A causal inference-based approach. PLoS Negl Trop Dis 2022; 16:e0010155. [PMID: 36037205 PMCID: PMC9462671 DOI: 10.1371/journal.pntd.0010155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 09/09/2022] [Accepted: 07/19/2022] [Indexed: 11/19/2022] Open
Abstract
Domestic and wild animals are important reservoirs of the rhodesiense form of human African trypanosomiasis (rHAT), however quantification of this effect offers utility for deploying non-medical control activities, and anticipating their success when wildlife are excluded. Further, the uncertain role of animal reservoirs-particularly pigs-threatens elimination of transmission (EOT) targets set for the gambiense form (gHAT). Using a new time series of high-resolution cattle and pig density maps, HAT surveillance data collated by the WHO Atlas of HAT, and methods drawn from causal inference and spatial epidemiology, we conducted a retrospective ecological cohort study in Uganda, Malawi, Democratic Republic of the Congo (DRC) and South Sudan to estimate the effect of cattle and pig density on HAT risk. For rHAT, we found a positive effect for cattle (RR 1.61, 95% CI 0.90, 2.99) and pigs (RR 2.07, 95% CI 1.15, 2.75) in Uganda, and a negative effect for cattle (RR 0.88, 95% CI 0.71, 1.10) and pigs (RR 0.42, 95% CI 0.23, 0.67) in Malawi. For gHAT we found a negative effect for cattle in Uganda (RR 0.88, 95% CI 0.50, 1.77) and South Sudan (RR 0.63, 95% CI 0.54, 0.77) but a positive effect in DRC (1.17, 95% CI 1.04, 1.32). For pigs, we found a positive gHAT effect in both Uganda (RR 2.02, 95% CI 0.87, 3.94) and DRC (RR 1.23, 95% CI 1.10, 1.37), and a negative association in South Sudan (RR 0.66, 95% CI 0.50, 0.98). These effects did not reach significance for the cattle-rHAT effect in Uganda or Malawi, or the cattle-gHAT and pig-gHAT effects in Uganda. While ecological bias may drive the findings in South Sudan, estimated E-values and simulation studies suggest unmeasured confounding and underreporting are unlikely to explain our findings in Malawi, Uganda, and DRC. Our results suggest cattle and pigs may be important reservoirs of rHAT in Uganda but not Malawi, and that pigs-and possibly cattle-may be gHAT reservoirs.
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Affiliation(s)
- Julianne Meisner
- Center for One Health Research, Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | | | | | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, Democratic Republic of the Congo
| | | | - Jonathan Wakefield
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
- Department of Statistics, University of Washington, Seattle, Washington, United States of America
| | - Ali Rowhani-Rahbar
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - David M. Pigott
- Department of Health Metrics Sciences, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Jonathan D. Mayer
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Peter M. Rabinowitz
- Center for One Health Research, Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
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Crump RE, Huang CI, Spencer SEF, Brown PE, Shampa C, Mwamba Miaka E, Rock KS. Modelling to infer the role of animals in gambiense human African trypanosomiasis transmission and elimination in the DRC. PLoS Negl Trop Dis 2022; 16:e0010599. [PMID: 35816487 PMCID: PMC9302778 DOI: 10.1371/journal.pntd.0010599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 07/21/2022] [Accepted: 06/22/2022] [Indexed: 11/18/2022] Open
Abstract
Gambiense human African trypanosomiasis (gHAT) has been targeted for elimination of transmission (EoT) to humans by 2030. Whilst this ambitious goal is rapidly approaching, there remain fundamental questions about the presence of non-human animal transmission cycles and their potential role in slowing progress towards, or even preventing, EoT. In this study we focus on the country with the most gHAT disease burden, the Democratic Republic of Congo (DRC), and use mathematical modelling to assess whether animals may contribute to transmission in specific regions, and if so, how their presence could impact the likelihood and timing of EoT. By fitting two model variants-one with, and one without animal transmission-to the human case data from 2000-2016 we estimate model parameters for 158 endemic health zones of the DRC. We evaluate the statistical support for each model variant in each health zone and infer the contribution of animals to overall transmission and how this could impact predicted time to EoT. We conclude that there are 24/158 health zones where there is substantial to decisive statistical support for some animal transmission. However-even in these regions-we estimate that animals would be extremely unlikely to maintain transmission on their own. Animal transmission could hamper progress towards EoT in some settings, with projections under continuing interventions indicating that the number of health zones expected to achieve EoT by 2030 reduces from 68/158 to 61/158 if animal transmission is included in the model. With supplementary vector control (at a modest 60% tsetse reduction) added to medical screening and treatment interventions, the predicted number of health zones meeting the goal increases to 147/158 for the model including animal transmission. This is due to the impact of vector reduction on transmission to and from all hosts.
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Affiliation(s)
- Ronald E. Crump
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Ching-I Huang
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Simon E. F. Spencer
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- The Department of Statistics, The University of Warwick, Coventry, United Kingdom
| | - Paul E. Brown
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
| | - Chansy Shampa
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Kat S. Rock
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, United Kingdom
- Mathematics Institute, The University of Warwick, Coventry, United Kingdom
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Desquesnes M, Sazmand A, Gonzatti M, Boulangé A, Bossard G, Thévenon S, Gimonneau G, Truc P, Herder S, Ravel S, Sereno D, Waleckx E, Jamonneau V, Jacquiet P, Jittapalapong S, Berthier D, Solano P, Hébert L. Diagnosis of animal trypanosomoses: proper use of current tools and future prospects. Parasit Vectors 2022; 15:235. [PMID: 35761373 PMCID: PMC9238167 DOI: 10.1186/s13071-022-05352-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/05/2022] [Indexed: 12/24/2022] Open
Abstract
Reliable diagnostic tools are needed to choose the appropriate treatment and proper control measures for animal trypanosomoses, some of which are pathogenic. Trypanosoma cruzi, for example, is responsible for Chagas disease in Latin America. Similarly, pathogenic animal trypanosomoses of African origin (ATAO), including a variety of Trypanosoma species and subspecies, are currently found in Africa, Latin America and Asia. ATAO limit global livestock productivity and impact food security and the welfare of domestic animals. This review focusses on implementing previously reviewed diagnostic methods, in a complex epizootiological scenario, by critically assessing diagnostic results at the individual or herd level. In most cases, a single diagnostic method applied at a given time does not unequivocally identify the various parasitological and disease statuses of a host. These include "non-infected", "asymptomatic carrier", "sick infected", "cured/not cured" and/or "multi-infected". The diversity of hosts affected by these animal trypanosomoses and their vectors (or other routes of transmission) is such that integrative, diachronic approaches are needed that combine: (i) parasite detection, (ii) DNA, RNA or antigen detection and (iii) antibody detection, along with epizootiological information. The specificity of antibody detection tests is restricted to the genus or subgenus due to cross-reactivity with other Trypanosoma spp. and Trypanosomatidae, but sensitivity is high. The DNA-based methods implemented over the last three decades have yielded higher specificity and sensitivity for active infection detection in hosts and vectors. However, no single diagnostic method can detect all active infections and/or trypanosome species or subspecies. The proposed integrative approach will improve the prevention, surveillance and monitoring of animal trypanosomoses with the available diagnostic tools. However, further developments are required to address specific gaps in diagnostic methods and the sustainable control or elimination of these diseases.
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Affiliation(s)
- Marc Desquesnes
- UMR INTERTRYP, French Agricultural Research Centre for International Development (CIRAD), 31076 Toulouse, France
- INTERTRYP, IRD, CIRAD, University of Montpellier, Montpellier, France
- National Veterinary School of Toulouse (ENVT), 23 chemin des Capelles, 31000 Toulouse, France
| | - Alireza Sazmand
- Department of Pathobiology, Faculty of Veterinary Science, Bu-Ali Sina University, Hamedan, 6517658978 Iran
| | - Marisa Gonzatti
- Department of Cell Biology, Simón Bolívar University, Caracas, 1080 Venezuela
| | - Alain Boulangé
- INTERTRYP, IRD, CIRAD, University of Montpellier, Montpellier, France
- UMR INTERTRYP, CIRAD, Bouaké, Côte d’Ivoire
- Pierre Richet Institute, National Public Health Institute, BP 1500 Bouaké, Côte d’Ivoire
| | - Géraldine Bossard
- INTERTRYP, IRD, CIRAD, University of Montpellier, Montpellier, France
- UMR INTERTRYP, CIRAD, 34398 Montpellier, France
| | - Sophie Thévenon
- INTERTRYP, IRD, CIRAD, University of Montpellier, Montpellier, France
- UMR INTERTRYP, CIRAD, 34398 Montpellier, France
| | - Geoffrey Gimonneau
- INTERTRYP, IRD, CIRAD, University of Montpellier, Montpellier, France
- UMR INTERTRYP, CIRAD , Dakar, Senegal
- National Laboratory for Livestock and Veterinary Research, Senegalese Institute on Agricultural Research (ISRA), BP 2057, Dakar, Hann Senegal
| | - Philippe Truc
- IRD, UMR INTERTRYP, University of Montpellier, Montpellier, France
| | - Stéphane Herder
- IRD, UMR INTERTRYP, University of Montpellier, Montpellier, France
| | - Sophie Ravel
- IRD, UMR INTERTRYP, University of Montpellier, Montpellier, France
| | - Denis Sereno
- IRD, UMR INTERTRYP, University of Montpellier, Montpellier, France
| | - Etienne Waleckx
- IRD, UMR INTERTRYP, University of Montpellier, Montpellier, France
- Regional Research Centre Dr. Hideyo Noguchi, Autonomous University of Yucatán, Mérida, Yucatán Mexico
| | | | - Philippe Jacquiet
- National Veterinary School of Toulouse (ENVT), 23 chemin des Capelles, 31000 Toulouse, France
| | | | - David Berthier
- INTERTRYP, IRD, CIRAD, University of Montpellier, Montpellier, France
- UMR INTERTRYP, CIRAD, 34398 Montpellier, France
| | - Philippe Solano
- IRD, UMR INTERTRYP, University of Montpellier, Montpellier, France
| | - Laurent Hébert
- Physiopathology & Epidemiology of Equine Diseases Unit (PhEED), Laboratory of Animal Health, Normandy Site, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Rd 675 Les Places, 14430 Goustranville, France
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Somda MB, Kaboré J, Karambiri SM, Dama E, Dabiré D, Compaoré CFA, Salou EW, Ilboudo H, Houaga I, Courtin F, Belem AMG, Jamonneau V, Bengaly Z. Evaluation of the Re-emergence Risk of Human African Trypanosomiasis in the Southwestern Burkina Faso, A Gold-Bearing Mutation Area. Acta Parasitol 2022; 67:714-722. [PMID: 35029802 DOI: 10.1007/s11686-021-00512-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 12/09/2021] [Indexed: 11/01/2022]
Abstract
PURPOSE The boom in Burkina Faso's artisanal gold mining since 2007 has attracted populations from Côte d'Ivoire and Guinea, which are the West African countries most affected by human African trypanosomiasis (HAT) and therefore increases its risk of re-emergence. Our aim was to update the HAT data in Burkina Faso in the risk of the re-emergence context with the advent of artisanal gold mining. METHODS The study was carried out in the southwestern Burkina Faso where entomological surveys were conducted using biconical traps in March 2017. Follow by an active medical survey in April 2017, which was targeted the gold panners in 7 villages closer to artisanal gold sites, using CATT, mini-anion exchange centrifugation technique, trypanolysis test (TL) and ELISA test to measure human/tsetse contacts. The buffy coat technique and the TL were also applied in pigs to check their reservoir role of human trypanosomes. RESULTS Our results have shown no case of HAT among 958 individuals tested and all the 50 pigs were also negative, but the level of antibodies against tsetse saliva evidenced by ELISA revealed low human/tsetse contact. Moreover, gold panners practise agriculture and breeding in an infected tsetse area, which are increased the risk. CONCLUSION Our results illustrate that the risk of re-emergence is low. The passive surveillance system implemented in 2015 in southwestern Burkina Faso is needed to increase the sentinel sites to better cover this area by taking into account the gold mining. Finally, awareness-raising activities are needed among populations about HAT.
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Rotureau B, Waleckx E, Jamonneau V, Solano P, Molia S, Debré P, Dellagi K, Morand S. Enhancing research integration to improve One Health actions: learning lessons from neglected tropical diseases experiences. BMJ Glob Health 2022; 7:bmjgh-2022-008881. [PMID: 35688485 PMCID: PMC9189848 DOI: 10.1136/bmjgh-2022-008881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 05/21/2022] [Indexed: 02/05/2023] Open
Affiliation(s)
- Brice Rotureau
- Parasitology Unit, Institut Pasteur of Guinea, Conakry, Guinea .,Trypanosome Transmission Group, Institut Pasteur, Paris, France
| | - Etienne Waleckx
- INTERTRYP - IRD, CIRAD, University of Montpellier, IRD, Montpellier, France.,Autonomous University of Yucatan, CIR Hideyo Noguchi, Merida, Mexico
| | - Vincent Jamonneau
- INTERTRYP - IRD, CIRAD, University of Montpellier, IRD, Montpellier, France
| | - Philippe Solano
- INTERTRYP - IRD, CIRAD, University of Montpellier, IRD, Montpellier, France
| | - Sophie Molia
- UMR ASTRE, CIRAD, Montpellier, France.,Univ Montpellier CIRAD INRAE, Montpellier, France
| | | | | | - Serge Morand
- CNRS MIVEGEC, IRD, Montpellier University, Montpellier, France.,Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand
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38
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African trypanosome strategies for conquering new hosts and territories: the end of monophyly? Trends Parasitol 2022; 38:724-736. [DOI: 10.1016/j.pt.2022.05.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 11/22/2022]
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Compaoré CFA, Kaboré J, Ilboudo H, Thomas LF, Falzon LC, Bamba M, Sakande H, Koné M, Kaba D, Bougouma C, Adama I, Amathe O, Belem AMG, Fèvre EM, Büscher P, Lejon V, Jamonneau V. Monitoring the elimination of gambiense human African trypanosomiasis in the historical focus of Batié, South-West Burkina Faso. Parasite 2022; 29:25. [PMID: 35543528 PMCID: PMC9093133 DOI: 10.1051/parasite/2022024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 04/19/2022] [Indexed: 11/21/2022] Open
Abstract
The World Health Organisation has targeted the elimination of human African trypanosomiasis (HAT) as zero transmission by 2030. Continued surveillance needs to be in place for early detection of re-emergent cases. In this context, the performance of diagnostic tests and testing algorithms for detection of the re-emergence of Trypanosoma brucei gambiense HAT remains to be assessed. We carried out a door-to-door active medical survey for HAT in the historical focus of Batié, South–West Burkina Faso. Screening was done using three rapid diagnostic tests (RDTs). Two laboratory tests (ELISA/T. b. gambiense and immune trypanolysis) and parasitological examination were performed on RDT positives only. In total, 5883 participants were screened, among which 842 (14%) tested positive in at least one RDT. Blood from 519 RDT positives was examined microscopically but no trypanosomes were observed. The HAT Sero-K-Set test showed the lowest specificity of 89%, while the specificities of SD Bioline HAT and rHAT Sero-Strip were 92% and 99%, respectively. The specificity of ELISA/T. b. gambiense and trypanolysis was 99% (98–99%) and 100% (99–100%), respectively. Our results suggest that T. b. gambiense is no longer circulating in the study area and that zero transmission has probably been attained. While a least cost analysis is still required, our study showed that RDT preselection followed by trypanolysis may be a useful strategy for post-elimination surveillance in Burkina Faso.
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Affiliation(s)
- Charlie Franck Alfred Compaoré
- Centre International de Recherche-Développement sur l'Élevage en zone Subhumide, Unité de recherche sur les maladies à vecteurs et biodiversité, 01 BP 454 Bobo-Dioulasso 01, Burkina Faso - Université Nazi Boni, Unité de Formation et de Recherche Sciences et Techniques, 01 BP 1091 Bobo-Dioulasso, Burkina-Faso
| | - Jacques Kaboré
- Centre International de Recherche-Développement sur l'Élevage en zone Subhumide, Unité de recherche sur les maladies à vecteurs et biodiversité, 01 BP 454 Bobo-Dioulasso 01, Burkina Faso - Université Nazi Boni, Unité de Formation et de Recherche Sciences et Techniques, 01 BP 1091 Bobo-Dioulasso, Burkina-Faso
| | - Hamidou Ilboudo
- Institut de Recherche en Sciences de la Santé, Unité de Recherche Clinique de Nanoro, 11 BP 218 Ouagadougou CMS 11, Burkina Faso
| | - Lian Francesca Thomas
- International Livestock Research Institute, PO Box 30709, Nairobi 00100, Kenya - University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences, Liverpool L69 3BX, United Kingdom
| | - Laura Cristina Falzon
- International Livestock Research Institute, PO Box 30709, Nairobi 00100, Kenya - University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences, Liverpool L69 3BX, United Kingdom
| | - Mohamed Bamba
- Centre International de Recherche-Développement sur l'Élevage en zone Subhumide, Unité de recherche sur les maladies à vecteurs et biodiversité, 01 BP 454 Bobo-Dioulasso 01, Burkina Faso
| | - Hassane Sakande
- Centre International de Recherche-Développement sur l'Élevage en zone Subhumide, Unité de recherche sur les maladies à vecteurs et biodiversité, 01 BP 454 Bobo-Dioulasso 01, Burkina Faso
| | - Minayégninrin Koné
- Institut Pierre Richet, Unité de Recherche et de Formation Trypanosomoses et Leishmanioses, 01 BP 1500 Bouake, Côte d'Ivoire
| | - Dramane Kaba
- Institut Pierre Richet, Unité de Recherche et de Formation Trypanosomoses et Leishmanioses, 01 BP 1500 Bouake, Côte d'Ivoire
| | - Clarisse Bougouma
- Programme National de Lutte contre les Maladies Tropicales Négligées, 03 BP 7009 Ouagadougou 03, Burkina Faso
| | - Ilboudo Adama
- Programme National de Lutte contre les Maladies Tropicales Négligées, 03 BP 7009 Ouagadougou 03, Burkina Faso
| | - Ouedraogo Amathe
- Programme National de Lutte contre les Maladies Tropicales Négligées, 03 BP 7009 Ouagadougou 03, Burkina Faso
| | - Adrien Marie Gaston Belem
- Université Nazi Boni, Unité de Formation et de Recherche Sciences et Techniques, 01 BP 1091 Bobo-Dioulasso, Burkina-Faso
| | - Eric Maurice Fèvre
- International Livestock Research Institute, PO Box 30709, Nairobi 00100, Kenya - University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences, Liverpool L69 3BX, United Kingdom
| | - Philippe Büscher
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Veerle Lejon
- Institut de Recherche pour le Développement, UMR INTERTRYP IRD-CIRAD, Université de Montpellier, TA A-17/G, Campus International de Baillarguet, 34398 Montpellier, France
| | - Vincent Jamonneau
- Institut Pierre Richet, Unité de Recherche et de Formation Trypanosomoses et Leishmanioses, 01 BP 1500 Bouake, Côte d'Ivoire - Institut de Recherche pour le Développement, UMR INTERTRYP IRD-CIRAD, Université de Montpellier, TA A-17/G, Campus International de Baillarguet, 34398 Montpellier, France
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Huang CI, Crump RE, Brown PE, Spencer SEF, Miaka EM, Shampa C, Keeling MJ, Rock KS. Identifying regions for enhanced control of gambiense sleeping sickness in the Democratic Republic of Congo. Nat Commun 2022; 13:1448. [PMID: 35304479 PMCID: PMC8933483 DOI: 10.1038/s41467-022-29192-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 02/28/2022] [Indexed: 11/08/2022] Open
Abstract
Gambiense human African trypanosomiasis (sleeping sickness, gHAT) is a disease targeted for elimination of transmission by 2030. While annual new cases are at a historical minimum, the likelihood of achieving the target is unknown. We utilised modelling to study the impacts of four strategies using currently available interventions, including active and passive screening and vector control, on disease burden and transmission across 168 endemic health zones in the Democratic Republic of the Congo. Median projected years of elimination of transmission show only 98 health zones are on track despite significant reduction in disease burden under medical-only strategies (64 health zones if > 90% certainty required). Blanket coverage with vector control is impractical, but is predicted to reach the target in all heath zones. Utilising projected disease burden under the uniform medical-only strategy, we provide a priority list of health zones for consideration for supplementary vector control alongside medical interventions.
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Affiliation(s)
- Ching-I Huang
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, UK.
- Mathematics Institute, The University of Warwick, Coventry, UK.
| | - Ronald E Crump
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, UK
- Mathematics Institute, The University of Warwick, Coventry, UK
- The School of Life Sciences, The University of Warwick, Coventry, UK
| | - Paul E Brown
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, UK
- Mathematics Institute, The University of Warwick, Coventry, UK
| | - Simon E F Spencer
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, UK
- The Department of Statistics, The University of Warwick, Coventry, UK
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Chansy Shampa
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of the Congo
| | - Matt J Keeling
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, UK
- Mathematics Institute, The University of Warwick, Coventry, UK
- The School of Life Sciences, The University of Warwick, Coventry, UK
| | - Kat S Rock
- Zeeman Institute for System Biology and Infectious Disease Epidemiology Research, The University of Warwick, Coventry, UK
- Mathematics Institute, The University of Warwick, Coventry, UK
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41
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Bemba I, Bamou R, Lenga A, Okoko A, Awono-Ambene P, Antonio-Nkondjio C. Review of the Situation of Human African Trypanosomiasis in the Republic of Congo From the 1950s to 2020. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:421-429. [PMID: 35137146 PMCID: PMC8924973 DOI: 10.1093/jme/tjab225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Indexed: 06/14/2023]
Abstract
Human African trypanosomiasis (HAT), despite considerable progress in the control, is still occurring in many countries in both west and central African regions. The HAT situation in the Republic of Congo has always been overshadowed by its neighbor the Democratic Republic of Congo where over 60% of all HAT cases occur. In the Republic of Congo, HAT cases have been significantly reduced to about 20 reported cases yearly and the disease is still prevalent in few foci across the country. Although continuous assessment of HAT situation in Congo is been led by the National Control Program for HAT, research on the vector, parasite, and vector control has received little attention. Because there have not been enough reviews summarizing key findings from studies conducted so far, there is still a poor understanding of the global situation of HAT in Congo. In order to achieve sustainable elimination of HAT in Congo a deep appraisal of HAT situation is required. The present study provides a review of studies conducted on HAT in the republic of Congo since the 1950s to date in order to identify gaps in knowledge and help consolidate the gains and progress towards the elimination of sleeping sickness.
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Affiliation(s)
- Irina Bemba
- Marien Ngouabi University, B.P. 69, Brazzaville, Republic of Congo
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
| | - Roland Bamou
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang, P.O. Box 067, Cameroon
| | - Arsene Lenga
- Marien Ngouabi University, B.P. 69, Brazzaville, Republic of Congo
| | - Aline Okoko
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
| | - Parfait Awono-Ambene
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
| | - Christophe Antonio-Nkondjio
- Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), B.P. 288, Yaoundé, Cameroun
- Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool, UK
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42
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Antillon M, Huang CI, Crump RE, Brown PE, Snijders R, Miaka EM, Keeling MJ, Rock KS, Tediosi F. Cost-effectiveness of sleeping sickness elimination campaigns in five settings of the Democratic Republic of Congo. Nat Commun 2022; 13:1051. [PMID: 35217656 PMCID: PMC8881616 DOI: 10.1038/s41467-022-28598-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 01/28/2022] [Indexed: 11/08/2022] Open
Abstract
Gambiense human African trypanosomiasis (gHAT) is marked for elimination of transmission by 2030, but the disease persists in several low-income countries. We couple transmission and health outcomes models to examine the cost-effectiveness of four gHAT elimination strategies in five settings - spanning low- to high-risk - of the Democratic Republic of Congo. Alongside passive screening in fixed health facilities, the strategies include active screening at average or intensified coverage levels, alone or with vector control with a scale-back algorithm when no cases are reported for three consecutive years. In high or moderate-risk settings, costs of gHAT strategies are primarily driven by active screening and, if used, vector control. Due to the cessation of active screening and vector control, most investments (75-80%) are made by 2030 and vector control might be cost-saving while ensuring elimination of transmission. In low-risk settings, costs are driven by passive screening, and minimum-cost strategies consisting of active screening and passive screening lead to elimination of transmission by 2030 with high probability.
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Affiliation(s)
- Marina Antillon
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Basel, 4123, Switzerland.
- University of Basel, Basel, 4001, Switzerland.
| | - Ching-I Huang
- Zeeman Institute, University of Warwick, Coventry, CV4 7AL, UK
- Mathematics Institute, University of Warwick, Coventry, CV4 7AL, UK
| | - Ronald E Crump
- Zeeman Institute, University of Warwick, Coventry, CV4 7AL, UK
- Mathematics Institute, University of Warwick, Coventry, CV4 7AL, UK
| | - Paul E Brown
- Zeeman Institute, University of Warwick, Coventry, CV4 7AL, UK
- Mathematics Institute, University of Warwick, Coventry, CV4 7AL, UK
| | - Rian Snijders
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Basel, 4123, Switzerland
- University of Basel, Basel, 4001, Switzerland
- Institute of Tropical Medicine, B-2000 Antwerp, Belgium
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Kinshasa, Democratic Republic of Congo
| | - Matt J Keeling
- Zeeman Institute, University of Warwick, Coventry, CV4 7AL, UK
- Mathematics Institute, University of Warwick, Coventry, CV4 7AL, UK
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Kat S Rock
- Zeeman Institute, University of Warwick, Coventry, CV4 7AL, UK.
- Mathematics Institute, University of Warwick, Coventry, CV4 7AL, UK.
| | - Fabrizio Tediosi
- Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Basel, 4123, Switzerland
- University of Basel, Basel, 4001, Switzerland
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43
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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: 53] [Impact Index Per Article: 26.5] [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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Maxamhud S, Lindahl JF, Mugenyi A, Echodu R, Waiswa C, Roesel K. Seasonal Monitoring of Glossina Species Occurrence, Infection Rates, and Trypanosoma Species Infections in Pigs in West Nile Region, Uganda. Vector Borne Zoonotic Dis 2022; 22:101-107. [PMID: 35175139 DOI: 10.1089/vbz.2020.2744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Introduction: Trypanosomiasis is a parasitic infection caused by the protozoa Trypanosoma. It is exclusively associated with Glossina species habitats and, therefore, restricted to specific geographical settings. It affects a wide range of hosts, including humans. Animals may carry different Trypanosoma spp. while being asymptomatic. They are, therefore, potentially important in unpremeditated disease transmission. Aim: The aim of this study was to study the potential impact of the government tsetse fly control program, and to elucidate the role of pigs in the Trypanosoma epidemiology in the West Nile region in Uganda. Methods: A historically important human African trypanosomiasis (HAT) hotspot was selected, with sampling in sites with and without a government tsetse fly control program. Pigs were screened for infection with Trypanosoma and tsetse traps were deployed to monitor vector occurrence, followed by tsetse fly dissection and microscopy to establish infection rates with Trypanosoma. Pig blood samples were further analyzed to identify possible Trypanosoma infections using internal transcribed spacer (ITS)-PCR. Results: Using microscopy, Trypanosoma was detected in 0.56% (7/1262) of the sampled pigs. Using ITS-PCR, 114 of 341 (33.4%) pig samples were shown to be Trypanosoma vivax positive. Of the 360 dissected tsetse flies, 13 (3.8%) were positive for Trypanosoma under the microscope. The difference in captured tsetse flies in the government intervention sites in comparison with the control sites was significant (p < 0.05). Seasonality did not play a substantial role in the tsetse fly density (p > 0.05). Conclusion: This study illustrated the impact of a government control program with low vector abundance in a historical HAT hotspot in Uganda. The study could not verify that pigs in the area were carriers for the causative agent for HAT, but showed a high prevalence of the animal infectious agent T. vivax.
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Affiliation(s)
- Sadiya Maxamhud
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Johanna F Lindahl
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.,Department of Biosciences, International Livestock Research Institute, Nairobi, Kenya.,Department of Clinical Sciences, Swedish University of Agricultural Science, Uppsala, Sweden
| | - Albert Mugenyi
- Coordinating Office for Control of Trypanosomiasis in Uganda, Ministry of Agriculture, Animal Industry and Fisheries, Makerere, Uganda
| | - Richard Echodu
- Department of Biology, Faculty of Science, Gulu University, Gulu, Uganda
| | - Charles Waiswa
- Coordinating Office for Control of Trypanosomiasis in Uganda, Ministry of Agriculture, Animal Industry and Fisheries, Makerere, Uganda.,Department of Pharmacy, Clinical and Comparative Studies, School of Veterinary Medicine and Animal Resources, Makerere University, Kampala, Uganda
| | - Kristina Roesel
- Department of Biosciences, International Livestock Research Institute, Nairobi, Kenya.,Department of Veterinary Medicine, Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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45
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Rock KS, Huang CI, Crump RE, Bessell PR, Brown PE, Tirados I, Solano P, Antillon M, Picado A, Mbainda S, Darnas J, Crowley EH, Torr SJ, Peka M. Update of transmission modelling and projections of gambiense human African trypanosomiasis in the Mandoul focus, Chad. Infect Dis Poverty 2022; 11:11. [PMID: 35074016 PMCID: PMC8785021 DOI: 10.1186/s40249-022-00934-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/03/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND In recent years, a programme of vector control, screening and treatment of gambiense human African trypanosomiasis (gHAT) infections led to a rapid decline in cases in the Mandoul focus of Chad. To represent the biology of transmission between humans and tsetse, we previously developed a mechanistic transmission model, fitted to data between 2000 and 2013 which suggested that transmission was interrupted by 2015. The present study outlines refinements to the model to: (1) Assess whether elimination of transmission has already been achieved despite low-level case reporting; (2) quantify the role of intensified interventions in transmission reduction; and (3) predict the trajectory of gHAT in Mandoul for the next decade under different strategies. METHOD Our previous gHAT transmission model for Mandoul was updated using human case data (2000-2019) and a series of model refinements. These include how diagnostic specificity is incorporated into the model and improvements to the fitting method (increased variance in observed case reporting and how underreporting and improvements to passive screening are captured). A side-by-side comparison of fitting to case data was performed between the models. RESULTS We estimated that passive detection rates have increased due to improvements in diagnostic availability in fixed health facilities since 2015, by 2.1-fold for stage 1 detection, and 1.5-fold for stage 2. We find that whilst the diagnostic algorithm for active screening is estimated to be highly specific (95% credible interval (CI) 99.9-100%, Specificity = 99.9%), the high screening and low infection levels mean that some recently reported cases with no parasitological confirmation might be false positives. We also find that the focus-wide tsetse reduction estimated through model fitting (95% CI 96.1-99.6%, Reduction = 99.1%) is comparable to the reduction previously measured by the decline in tsetse catches from monitoring traps. In line with previous results, the model suggests that transmission was interrupted in 2015 due to intensified interventions. CONCLUSIONS We recommend that additional confirmatory testing is performed in Mandoul to ensure the endgame can be carefully monitored. More specific measurement of cases, would better inform when it is safe to stop active screening and vector control, provided there is a strong passive surveillance system in place.
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Affiliation(s)
- Kat S Rock
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK.
- Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK.
| | - Ching-I Huang
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK
- Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK
| | - Ronald E Crump
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK
- Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK
| | | | - Paul E Brown
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK
- Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK
| | - Inaki Tirados
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Philippe Solano
- Institut de Recherche pour le Développement, UMR INTERTRYP IRD-CIRAD, Université de Montpellier, 34398, Montpellier, France
| | - Marina Antillon
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Albert Picado
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | - Severin Mbainda
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Moundou, Chad
| | - Justin Darnas
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Moundou, Chad
| | - Emily H Crowley
- Mathematics Institute, University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK
- Zeeman Institute for Systems Biology & Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Academic Loop Road, Coventry, CV4 7AL, UK
| | - Steve J Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Mallaye Peka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Moundou, Chad
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46
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Franco JR, Cecchi G, Paone M, Diarra A, Grout L, Kadima Ebeja A, Simarro PP, Zhao W, Argaw D. The elimination of human African trypanosomiasis: Achievements in relation to WHO road map targets for 2020. PLoS Negl Trop Dis 2022; 16:e0010047. [PMID: 35041668 PMCID: PMC8765662 DOI: 10.1371/journal.pntd.0010047] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 12/02/2021] [Indexed: 11/19/2022] Open
Abstract
Background In the 20th century, epidemics of human African trypanosomiasis (HAT) ravaged communities in a number of African countries. The latest surge in disease transmission was recorded in the late 1990s, with more than 35,000 cases reported annually in 1997 and 1998. In 2013, after more than a decade of sustained control efforts and steady progress, the World Health Assembly resolved to target the elimination of HAT as a public health problem by 2020. We report here on recent progress towards this goal. Methodology/principal findings With 992 and 663 cases reported in 2019 and 2020 respectively, the first global target was amply achieved (i.e. fewer than 2,000 HAT cases/year). Areas at moderate or higher risk of HAT, where more than 1 case/10,000 people/year are reported, shrunk to 120,000 km2 for the five-year period 2016–2020. This reduction of 83% from the 2000–2004 baseline (i.e. 709,000 km2) is slightly below the target (i.e. 90% reduction). As a result, the second global target for HAT elimination as a public health problem cannot be considered fully achieved yet. The number of health facilities able to diagnose and treat HAT expanded (+9.6% compared to a 2019 survey), thus reinforcing the capacity for passive detection and improving epidemiological knowledge of the disease. Active surveillance for gambiense HAT was sustained. In particular, 2.8 million people were actively screened in 2019 and 1.6 million in 2020, the decrease in 2020 being mainly caused by COVID-19-related restrictions. Togo and Côte d’Ivoire were the first countries to be validated for achieving elimination of HAT as a public health problem at the national level; applications from three additional countries are under review by the World Health Organization (WHO). Conclusions/significance The steady progress towards the elimination of HAT is a testament to the power of multi-stakeholder commitment and coordination. At the end of 2020, the World Health Assembly endorsed a new road map for 2021–2030 that set new bold targets for neglected tropical diseases. While rhodesiense HAT remains among the diseases targeted for elimination as a public health problem, gambiense HAT is targeted for elimination of transmission. The goal for gambiense HAT is expected to be particularly arduous, as it might be hindered by cryptic reservoirs and a number of other challenges (e.g. further integration of HAT surveillance and control into national health systems, availability of skilled health care workers, development of more effective and adapted tools, and funding for and coordination of elimination efforts). Human African trypanosomiasis (HAT) is a lethal neglected tropical disease (NTD) transmitted by the bite of infected tsetse flies. The disease is also known as “sleeping sickness”. During the 20th century it caused enormous suffering in the endemic areas in sub-Saharan Africa. HAT transmission last soared in the late 1990s, triggering a renewed, coordinated and very successful control effort. In this paper, we present achievements towards HAT elimination, with a focus on the WHO road map targets for 2020. In particular, reported cases continue to decline, from over 30,000 cases per year at the turn of the century to 663 cases in 2020. Despite the impact of the COVID-19 pandemic, HAT surveillance was largely sustained, and the network of health facilities able to diagnose and treat the disease further expanded. Looking to the future, the World Health Organization (WHO) set bold new targets for HAT in its 2021–2030 road map for NTDs, namely: the elimination of transmission of gambiense HAT, which occurs in western and central Africa, and the elimination as a public health problem of rhodesiense HAT, which is found in eastern and southern Africa. The strong commitment of national health authorities and the international community will be essential if these goals are to be achieved.
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Affiliation(s)
- Jose R. Franco
- World Health Organization, Control of Neglected Tropical Diseases, Prevention Treatment and Care, Geneva, Switzerland
- * E-mail:
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Massimo Paone
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Abdoulaye Diarra
- World Health Organization, Regional Office for Africa, Communicable Disease Unit, Brazzaville, Congo
| | - Lise Grout
- World Health Organization, Control of Neglected Tropical Diseases, Prevention Treatment and Care, Geneva, Switzerland
| | - Augustin Kadima Ebeja
- World Health Organization, Regional Office for Africa, Communicable Disease Unit, Brazzaville, Congo
| | - Pere P. Simarro
- Consultant, World Health Organization, Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, Geneva, Switzerland
| | - Weining Zhao
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Daniel Argaw
- World Health Organization, Control of Neglected Tropical Diseases, Prevention Treatment and Care, Geneva, Switzerland
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Free-ranging pigs identified as a multi-reservoir of Trypanosoma brucei and Trypanosoma congolense in the Vavoua area, a historical sleeping sickness focus of Côte d'Ivoire. PLoS Negl Trop Dis 2021; 15:e0010036. [PMID: 34937054 PMCID: PMC8735613 DOI: 10.1371/journal.pntd.0010036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 01/06/2022] [Accepted: 11/28/2021] [Indexed: 12/03/2022] Open
Abstract
Background The existence of an animal reservoir of Trypanosoma brucei gambiense (T. b. gambiense), the agent of human African trypanosomiasis (HAT), may compromise the interruption of transmission targeted by World Health Organization. The aim of this study was to investigate the presence of trypanosomes in pigs and people in the Vavoua HAT historical focus where cases were still diagnosed in the early 2010’s. Methods For the human survey, we used the CATT, mini-anion exchange centrifugation technique and immune trypanolysis tests. For the animal survey, the buffy coat technique was also used as well as the PCR using Trypanosoma species specific, including the T. b. gambiense TgsGP detection using single round and nested PCRs, performed from animal blood samples and from strains isolated from subjects positive for parasitological investigations. Results No HAT cases were detected among 345 people tested. A total of 167 pigs were investigated. Free-ranging pigs appeared significantly more infected than pigs in pen. Over 70% of free-ranging pigs were positive for CATT and parasitological investigations and 27–43% were positive to trypanolysis depending on the antigen used. T. brucei was the most prevalent species (57%) followed by T. congolense (24%). Blood sample extracted DNA of T. brucei positive subjects were negative to single round TgsGP PCR. However, 1/22 and 6/22 isolated strains were positive with single round and nested TgsGP PCRs, respectively. Discussion Free-ranging pigs were identified as a multi-reservoir of T. brucei and/or T. congolense with mixed infections of different strains. This trypanosome diversity hinders the easy and direct detection of T. b. gambiense. We highlight the lack of tools to prove or exclude with certainty the presence of T. b. gambiense. This study once more highlights the need of technical improvements to explore the role of animals in the epidemiology of HAT. Significant efforts to control human African trypanosomiasis (HAT) since the 1990’s have drastically reduced the prevalence of the disease. Its elimination as a public health problem is being achieved. World Health Organization now targets the interruption of transmission for 2030. However, potential animal reservoirs of Trypanosoma brucei gambiense (T. b. gambiense), the main agent of HAT, may compromise this ambitious objective. It is the case in the Vavoua historical focus in Côte d’Ivoire where HAT cases were still diagnosed in the early 2010’s. During a study conducted in this area, we scrutinized the trypanosomes circulating in pigs and people sharing the same environment using serological, immunological, parasitological and molecular tools. No HAT cases were detected. We showed that T. brucei s.l. and T. congolense actively circulated in free-ranging pigs. Even if no tools were sensitive and specific enough to unambiguously identify T. b. gambiense directly from biological samples, six isolated strains from pigs positive for trypanosomes were amplified for TgsGP, the only currently accepted T. b. gambiense specific molecular marker. The apparent discrepancies between the presence of T. b. gambiense in pigs despite the absence of human cases is discussed. These results stress the need for an efficient “molecular toolbox” to easily detect and identify T. b. gambiense in any animal it may infect.
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Das AM, Chitnis N, Burri C, Paris DH, Patel S, Spencer SEF, Miaka EM, Castaño MS. Modelling the impact of fexinidazole use on human African trypanosomiasis (HAT) transmission in the Democratic Republic of the Congo. PLoS Negl Trop Dis 2021; 15:e0009992. [PMID: 34843475 PMCID: PMC8659363 DOI: 10.1371/journal.pntd.0009992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 12/09/2021] [Accepted: 11/12/2021] [Indexed: 11/18/2022] Open
Abstract
Gambiense human African trypanosomiasis is a deadly disease that has been declining in incidence since the start of the Century, primarily due to increased screening, diagnosis and treatment of infected people. The main treatment regimen currently in use requires a lumbar puncture as part of the diagnostic process to determine disease stage and hospital admission for drug administration. Fexinidazole is a new oral treatment for stage 1 and non-severe stage 2 human African trypanosomiasis. The World Health Organization has recently incorporated fexinidazole into its treatment guidelines for human African trypanosomiasis. The treatment does not require hospital admission or a lumbar puncture for all patients, which is likely to ease access for patients; however, it does require concomitant food intake, which is likely to reduce adherence. Here, we use a mathematical model calibrated to case and screening data from Mushie territory, in the Democratic Republic of the Congo, to explore the potential negative impact of poor compliance to an oral treatment, and potential gains to be made from increases in the rate at which patients seek treatment. We find that reductions in compliance in treatment of stage 1 cases are projected to result in the largest increase in further transmission of the disease, with failing to cure stage 2 cases also posing a smaller concern. Reductions in compliance may be offset by increases in the rate at which cases are passively detected. Efforts should therefore be made to ensure good adherence for stage 1 patients to treatment with fexinidazole and to improve access to care. Sleeping sickness is a parasitic disease present in parts of Central and West Africa that is fatal if left untreated. Current case management requires unpleasant procedures such as a lumbar puncture and intravenous drug administration, but has high compliance rates as the treatment is given by hospital staff to patients. In this study, we explore the impact of a new oral treatment on compliance rates for treatment using a mathematical model fitted to data on sleeping sickness cases and screening activities. We also look at the possibility of patients being more likely to seek and access treatment since the new treatment can be used without a lumbar puncture if the patient does not display clinically severe symptoms. We find that reduced compliance, especially from patients suffering from the first less severe stage of the disease, will lead to more sleeping sickness cases and delay elimination, but increases in the number of patients seeking treatment will likely counter effects of reduced compliance.
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Affiliation(s)
- Aatreyee M. Das
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Christian Burri
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Daniel H. Paris
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Swati Patel
- Department of Statistics, University of Warwick, Coventry, United Kingdom
- Department of Mathematics, Oregon State University, Corvallis, Oregon, United States of America
| | | | - Erick M. Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, the Democratic Republic of the Congo
| | - M. Soledad Castaño
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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Raman spectroscopic analysis of skin as a diagnostic tool for Human African Trypanosomiasis. PLoS Pathog 2021; 17:e1010060. [PMID: 34780575 PMCID: PMC8629383 DOI: 10.1371/journal.ppat.1010060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 11/29/2021] [Accepted: 10/23/2021] [Indexed: 02/08/2023] Open
Abstract
Human African Trypanosomiasis (HAT) has been responsible for several deadly epidemics throughout the 20th century, but a renewed commitment to disease control has significantly reduced new cases and motivated a target for the elimination of Trypanosoma brucei gambiense-HAT by 2030. However, the recent identification of latent human infections, and the detection of trypanosomes in extravascular tissues hidden from current diagnostic tools, such as the skin, has added new complexity to identifying infected individuals. New and improved diagnostic tests to detect Trypanosoma brucei infection by interrogating the skin are therefore needed. Recent advances have improved the cost, sensitivity and portability of Raman spectroscopy technology for non-invasive medical diagnostics, making it an attractive tool for gambiense-HAT detection. The aim of this work was to assess and develop a new non-invasive diagnostic method for T. brucei through Raman spectroscopy of the skin. Infections were performed in an established murine disease model using the animal-infective Trypanosoma brucei brucei subspecies. The skin of infected and matched control mice was scrutinized ex vivo using a confocal Raman microscope with 532 nm excitation and in situ at 785 nm excitation with a portable field-compatible instrument. Spectral evaluation and Principal Component Analysis confirmed discrimination of T. brucei-infected from uninfected tissue, and a characterisation of biochemical changes in lipids and proteins in parasite-infected skin indicated by prominent Raman peak intensities was performed. This study is the first to demonstrate the application of Raman spectroscopy for the detection of T. brucei by targeting the skin of the host. The technique has significant potential to discriminate between infected and non-infected tissue and could represent a unique, non-invasive diagnostic tool in the goal for elimination of gambiense-HAT as well as for Animal African Trypanosomiasis (AAT). Human African Trypanosomiasis (HAT), also known as sleeping sickness, is a disease caused by the parasite Trypanosoma brucei and has been responsible for the death of millions of people across Africa in the 20th century. It is also a major economic burden for countries endemic for trypanosomiasis, affecting livestock productivity in rural areas (Animal African Trypanosomiasis). A long-term international collaboration with the help of the World Health Organisation has resulted in the rate of human infection decreasing to less than 1000 new cases per year. However, the human disease continues to spread within remote villages. Current diagnosis is based on the detection of parasites in blood and serum samples, but this is challenging during chronic human infections with low or non-detectable parasitaemia. However, the recent discovery of extravascular skin-dwelling trypanosomes indicates that a reservoir of infection remains undetected, threatening the effort to eliminate the disease. In this study we have targeted the skin as a site for diagnosis using Raman spectroscopy and demonstrate that this method showed great promise in the laboratory, laying the foundation for field studies to examine its potential to strengthen current diagnostic strategies for detecting HAT cases.
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Single nucleotide polymorphisms and copy-number variations in the Trypanosoma brucei repeat (TBR) sequence can be used to enhance amplification and genotyping of Trypanozoon strains. PLoS One 2021; 16:e0258711. [PMID: 34695154 PMCID: PMC8544829 DOI: 10.1371/journal.pone.0258711] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/04/2021] [Indexed: 11/19/2022] Open
Abstract
The Trypanosoma brucei repeat (TBR) is a tandem repeat sequence present on the Trypanozoon minichromosomes. Here, we report that the TBR sequence is not as homogenous as previously believed. BLAST analysis of the available T. brucei genomes reveals various TBR sequences of 177 bp and 176 bp in length, which can be sorted into two TBR groups based on a few key single nucleotide polymorphisms. Conventional and quantitative PCR with primers matched to consensus sequences that target either TBR group show substantial copy-number variations in the TBR repertoire within a collection of 77 Trypanozoon strains. We developed the qTBR, a novel PCR consisting of three primers and two probes, to simultaneously amplify target sequences from each of the two TBR groups into one single qPCR reaction. This dual probe setup offers increased analytical sensitivity for the molecular detection of all Trypanozoon taxa, in particular for T.b. gambiense and T. evansi, when compared to existing TBR PCRs. By combining the qTBR with 18S rDNA amplification as an internal standard, the relative copy-number of each TBR target sequence can be calculated and plotted, allowing for further classification of strains into TBR genotypes associated with East, West or Central Africa. Thus, the qTBR takes advantage of the single-nucleotide polymorphisms and copy number variations in the TBR sequences to enhance amplification and genotyping of all Trypanozoon strains, making it a promising tool for prevalence studies of African trypanosomiasis in both humans and animals.
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