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Ramos-Soriano J, Holbrow-Wilshaw M, Hunt E, Jiang YJ, Peñalver P, Morales JC, Galan MC. Probing the binding and antiparasitic efficacy of azobenzene G-quadruplex ligands to investigate G4 ligand design. Chem Commun (Camb) 2024. [PMID: 39308448 PMCID: PMC11418008 DOI: 10.1039/d4cc03106g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Accepted: 09/10/2024] [Indexed: 09/25/2024]
Abstract
Novel strategies against parasitic infections are of great importance. Here, we describe a G4 DNA ligand with subnanomolar antiparasitic activity against T. brucei and a remarkable selectivity index (IC50 MRC-5/T. brucei) of 2285-fold. We also correlate the impact of small structural changes to G4 binding activity and antiparasitic activity.
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Affiliation(s)
| | | | - Eliza Hunt
- School of Chemistry, Cantock's Close, University of Bristol, BS8 1TS, UK
| | - Y Jennifer Jiang
- School of Chemistry, Cantock's Close, University of Bristol, BS8 1TS, UK
| | - Pablo Peñalver
- Instituto de Parasitología y Biomedicina López Neyra, CSIC, PTS Granada, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain.
| | - Juan C Morales
- Instituto de Parasitología y Biomedicina López Neyra, CSIC, PTS Granada, Avenida del Conocimiento, 17, 18016, Armilla, Granada, Spain.
| | - M Carmen Galan
- School of Chemistry, Cantock's Close, University of Bristol, BS8 1TS, UK
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2
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Odeniran PO, Paul-Odeniran KF, Ademola IO. The comprehensive epidemiological status of human African trypanosomiasis in Nigeria: meta-analysis and systematic review of the full story (1962-2022). Parasitol Res 2024; 123:291. [PMID: 39102014 DOI: 10.1007/s00436-024-08312-z] [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: 06/10/2024] [Accepted: 07/29/2024] [Indexed: 08/06/2024]
Abstract
Human African trypanosomiasis (HAT) in Nigeria is caused primarily by Trypanosoma brucei gambiense (gHAT), which has historically been a major human and animal health problem. This study aims to examine the status of gHAT in Nigeria over the past 60 years. The World Health Organization (WHO) set two targets to eliminate HAT as a public health concern by 2020 and terminate its global transmission by 2030. The former target has been achieved, but accurate monitoring and surveillance are important for maintaining this success and delivering the second target. Although recent cases in Nigeria are rare, accurately estimating the national seroprevalence and actual prevalence of gHATs remains challenging. To address this, a meta-analysis reviewed studies on gHATs in Nigeria from databases such as Embase, Global Health, Ovid Medline, Web of Science, and Google Scholar. Ten studies were included, ranging between 1962 and 2016, covering 52 clusters and 5,671,877 individuals, even though databases were scrutinized up to 2022. The seroprevalence ranged from 1.75 to 17.07%, with an overall estimate of 5.01% (95% CI 1.72-9.93). The actual gHAT prevalence detected by parasitological or PCR methods was 0.001 (95% CI 0.000-0.002), indicating a prevalence of 0.1%. Notably, the seroprevalence was greater in southern Nigeria than in northern Nigeria. These findings suggest that the disease might be spreading unnoticed due to the increased movement of people from endemic areas. This study highlights the paucity of studies in Nigeria over the last 60 years and emphasizes the need for further research, systematic surveillance, and proper reporting methods throughout the country.
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Affiliation(s)
- Paul Olalekan Odeniran
- Department of Veterinary Parasitology and Entomology, University of Ibadan, Ibadan, 200001, Nigeria.
| | | | - Isaiah Oluwafemi Ademola
- Department of Veterinary Parasitology and Entomology, University of Ibadan, Ibadan, 200001, Nigeria
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3
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Hudu SA, Jimoh AO, Adeshina KA, Otalike EG, Tahir A, Hegazy AA. An insight into the Success, Challenges, and Future perspectives of eliminating Neglected tropical disease. SCIENTIFIC AFRICAN 2024; 24:e02165. [DOI: 10.1016/j.sciaf.2024.e02165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2024] Open
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4
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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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5
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Varghese S, Srivastava A, Wong SW, Le T, Pitcher N, Mesnard M, Lallemand C, Rahmani R, Moawad SR, Huang F, He T, Sleebs BE, Barrett MP, Sykes ML, Avery VM, Creek DJ, Baell JB. Novel aroyl guanidine anti-trypanosomal compounds that exert opposing effects on parasite energy metabolism. Eur J Med Chem 2024; 268:116162. [PMID: 38394930 DOI: 10.1016/j.ejmech.2024.116162] [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: 11/07/2023] [Revised: 01/05/2024] [Accepted: 01/16/2024] [Indexed: 02/25/2024]
Abstract
Human African trypanosomiasis (HAT), or sleeping sickness, is a neglected tropical disease with current treatments marred by severe side effects or delivery issues. To identify novel classes of compounds for the treatment of HAT, high throughput screening (HTS) had previously been conducted on bloodstream forms of T. b. brucei, a model organism closely related to the human pathogens T. b. gambiense and T. b. rhodesiense. This HTS had identified a number of structural classes with potent bioactivity against T. b. brucei (IC50 ≤ 10 μM) with selectivity over mammalian cell-lines (selectivity index of ≥10). One of the confirmed hits was an aroyl guanidine derivative. Deemed to be chemically tractable with attractive physicochemical properties, here we explore this class further to develop the SAR landscape. We also report the influence of the elucidated SAR on parasite metabolism, to gain insight into possible modes of action of this class. Of note, two sub-classes of analogues were identified that generated opposing metabolic responses involving disrupted energy metabolism. This knowledge may guide the future design of more potent inhibitors, while retaining the desirable physicochemical properties and an excellent selectivity profile of the current compound class.
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Affiliation(s)
- Swapna Varghese
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Anubhav Srivastava
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Siu Wai Wong
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Thuy Le
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Noel Pitcher
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Mathilda Mesnard
- Ensemble Scientifique des Cézeaux, 24 avenue des Landais, 63170, Aubière, France
| | - Camille Lallemand
- Ensemble Scientifique des Cézeaux, 24 avenue des Landais, 63170, Aubière, France
| | - Raphael Rahmani
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Sarah R Moawad
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia
| | - Fei Huang
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, China
| | - Tiantong He
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, China
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, 3052, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, 3010, Australia
| | - Michael P Barrett
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Melissa L Sykes
- Discovery Biology, Centre for Cellular Phenomics, Griffith University, Nathan, Queensland, 4111, Australia
| | - Vicky M Avery
- Discovery Biology, Centre for Cellular Phenomics, Griffith University, Nathan, Queensland, 4111, Australia; School of Environment and Science, Griffith University, Nathan, QLD, 4111, Australia
| | - Darren J Creek
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia.
| | - Jonathan B Baell
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia; School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, China.
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6
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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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7
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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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8
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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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9
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Mwiinde AM, Simuunza M, Namangala B, Chama-Chiliba CM, Machila N, Anderson NE, Atkinson PM, Welburn SC. Healthcare Management of Human African Trypanosomiasis Cases in the Eastern, Muchinga and Lusaka Provinces of Zambia. Trop Med Infect Dis 2022; 7:270. [PMID: 36288011 PMCID: PMC9607271 DOI: 10.3390/tropicalmed7100270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/16/2022] [Accepted: 09/16/2022] [Indexed: 11/26/2022] Open
Abstract
Human African trypanosomiasis (HAT) is a neglected tropical disease that has not received much attention in Zambia and most of the countries in which it occurs. In this study, we assessed the adequacy of the healthcare delivery system in diagnosis and management of rHAT cases, the environmental factors associated with transmission, the population at risk and the geographical location of rHAT cases. Structured questionnaires, focus group discussions and key informant interviews were conducted among the affected communities and health workers. The study identified 64 cases of rHAT, of which 26 were identified through active surveillance and 38 through passive surveillance. We identified a significant association between knowledge of the vector for rHAT and knowledge of rHAT transmission (p < 0.028). In all four districts, late or poor diagnosis occurred due to a lack of qualified laboratory technicians and diagnostic equipment. This study reveals that the current Zambian healthcare system is not able to adequately handle rHAT cases. Targeted policies to improve staff training in rHAT disease detection and management are needed to ensure that sustainable elimination of this public health problem is achieved in line with global targets.
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Affiliation(s)
- Allan Mayaba Mwiinde
- Department of Public Health, Mazabuka Municipal Council, Mazabuka P.O. Box 620033, Zambia
- School of Veterinary Medicine, University of Zambia, Lusaka P.O. Box 50110, Zambia
| | - Martin Simuunza
- School of Veterinary Medicine, University of Zambia, Lusaka P.O. Box 50110, Zambia
| | - Boniface Namangala
- School of Veterinary Medicine, University of Zambia, Lusaka P.O. Box 50110, Zambia
| | | | - Noreen Machila
- School of Veterinary Medicine, University of Zambia, Lusaka P.O. Box 50110, Zambia
- School of Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Neil E. Anderson
- The Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, 49 Little France Crescent, Edinburgh EH25 9RG, UK
| | - Peter M. Atkinson
- Centre for Health Informatics, Computing and Statistics (CHICAS), Lancaster Medical School, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YQ, UK
| | - Susan C. Welburn
- School of Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
- Zhejiang University-University of Edinburgh Joint Institute, Zhejiang University, International Campus, 718 East Haizhou Road, Haining 314400, China
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10
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Mousavi A, Foroumadi P, Emamgholipour Z, Mäser P, Kaiser M, Foroumadi A. 2-(Nitroaryl)-5-Substituted-1,3,4-Thiadiazole Derivatives with Antiprotozoal Activities: In Vitro and In Vivo Study. Molecules 2022; 27:molecules27175559. [PMID: 36080325 PMCID: PMC9457997 DOI: 10.3390/molecules27175559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
Nitro-containing compounds are a well-known class of anti-infective agents, especially in the field of anti-parasitic drug discovery. HAT or sleeping sickness is a neglected tropical disease caused by a protozoan parasite, Trypanosoma brucei. Following the approval of fexinidazole as the first oral treatment for both stages of T. b. gambiense HAT, there is an increased interest in developing new nitro-containing compounds against parasitic diseases. In our previous projects, we synthesized several megazole derivatives that presented high activity against Leishmania major promastigotes. Here, we screened and evaluated their trypanocidal activity. Most of the compounds showed submicromolar IC50 against the BSF form of T. b. rhodesiense (STIB 900). To the best of our knowledge, compound 18c is one of the most potent nitro-containing agents reported against HAT in vitro. Compound 18g revealed an acceptable cure rate in the acute mouse model of HAT, accompanied with noteworthy in vitro activity against T. brucei, T. cruzi, and L. donovani. Taken together, these results suggest that these compounds are promising candidates to evaluate their pharmacokinetic and biological profiles in the future.
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Affiliation(s)
- Alireza Mousavi
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417614411, Iran
| | - Parham Foroumadi
- Department of Medicinal Chemistry, School of Pharmacy, International Campus, Tehran University of Medical Sciences, Tehran 1417614411, Iran
| | - Zahra Emamgholipour
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417614411, Iran
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
- Faculty of Science, University of Basel, 4002 Basel, Switzerland
| | - Marcel Kaiser
- Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
- Faculty of Science, University of Basel, 4002 Basel, Switzerland
- Correspondence: (M.K.); (A.F.)
| | - Alireza Foroumadi
- Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran 1417614411, Iran
- Drug Design and Development Research Center, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran 1417614411, Iran
- Correspondence: (M.K.); (A.F.)
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11
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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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12
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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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13
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Lutje V, Probyn K, Seixas J, Bergman H, Villanueva G. Chemotherapy for second-stage human African trypanosomiasis: drugs in use. Cochrane Database Syst Rev 2021; 12:CD015374. [PMID: 34882307 PMCID: PMC8656462 DOI: 10.1002/14651858.cd015374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Human African trypanosomiasis, or sleeping sickness, is a severe disease affecting people in the poorest parts of Africa. It is usually fatal without treatment. Conventional treatments require days of intravenous infusion, but a recently developed drug, fexinidazole, can be given orally. Another oral drug candidate, acoziborole, is undergoing clinical development and will be considered in subsequent editions. OBJECTIVES: To evaluate the effectiveness and safety of currently used drugs for treating second-stage Trypanosoma brucei gambiense trypanosomiasis (gambiense human African trypanosomiasis, g-HAT). SEARCH METHODS On 14 May 2021, we searched the Cochrane Infectious Diseases Group Specialized Register, the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, Latin American and Caribbean Health Science Information database, BIOSIS, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. We also searched reference lists of included studies, contacted researchers working in the field, and contacted relevant organizations. SELECTION CRITERIA Eligible studies were randomized controlled trials that included adults and children with second-stage g-HAT, treated with anti-trypanosomal drugs currently in use. DATA COLLECTION AND ANALYSIS Two review authors extracted data and assessed risk of bias; a third review author acted as an arbitrator if needed. The included trial only reported dichotomous outcomes, which we presented as risk ratio (RR) or risk difference (RD) with 95% confidence intervals (CI). MAIN RESULTS: We included one trial comparing fexinidazole to nifurtimox combined with eflornithine (NECT). This trial was conducted between October 2012 and November 2016 in the Democratic Republic of the Congo and the Central African Republic, and included 394 participants. The study reported on efficacy and safety, with up to 24 months' follow-up. We judged the study to be at low risk of bias in all domains except blinding; as the route of administration and dosing regimens differed between treatment groups, participants and personnel were not blinded, resulting in a high risk of performance bias. Mortality with fexinidazole may be higher at 24 months compared to NECT. There were 9/264 deaths in the fexinidazole group and 2/130 deaths in the NECT group (RR 2.22, 95% CI 0.49 to 10.11; 394 participants; low-certainty evidence). None of the deaths were related to treatment. Fexinidazole likely results in an increase in the number of people relapsing during follow-up, with 14 participants in the fexinidazole group (14/264) and none in the NECT group (0/130) relapsing at 24 months (RD 0.05, 95% CI 0.02 to 0.08; 394 participants; moderate-certainty evidence). We are uncertain whether there is any difference between the drugs regarding the incidence of serious adverse events at 24 months. (31/264 with fexinidazole and 13/130 with NECT group at 24 months). Adverse events were common with both drugs (247/264 with fexinidazole versus 121/130 with NECT), with no difference between groups (RR 1.01, 95% CI 0.95 to 1.06; 394 participants; moderate-certainty evidence). AUTHORS' CONCLUSIONS: Oral treatment with fexinidazole is much easier to administer than conventional treatment, but deaths and relapse appear to be more common. However, the advantages or an oral option are considerable, in terms of convenience, avoiding hospitalisation and multiple intravenous infusions, thus increasing adherence.
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Affiliation(s)
- Vittoria Lutje
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Jorge Seixas
- Institute of Hygiene and Tropical Medicine and Global Health and Tropical Medicine R&D Center, NOVA University, Lisbon, Portugal
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Opiro R, Opoke R, Angwech H, Nakafu E, Oloya FA, Openy G, Njahira M, Macharia M, Echodu R, Malinga GM, Opiyo EA. Apparent density, trypanosome infection rates and host preference of tsetse flies in the sleeping sickness endemic focus of northwestern Uganda. BMC Vet Res 2021; 17:365. [PMID: 34839816 PMCID: PMC8628410 DOI: 10.1186/s12917-021-03071-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 11/13/2021] [Indexed: 11/11/2022] Open
Abstract
Background African trypanosomiasis, caused by protozoa of the genus Trypanosoma and transmitted by the tsetse fly, is a serious parasitic disease of humans and animals. Reliable data on the vector distribution, feeding preference and the trypanosome species they carry is pertinent to planning sustainable control strategies. Methodology We deployed 109 biconical traps in 10 villages in two districts of northwestern Uganda to obtain information on the apparent density, trypanosome infection status and blood meal sources of tsetse flies. A subset (272) of the collected samples was analyzed for detection of trypanosomes species and sub-species using a nested PCR protocol based on primers amplifying the Internal Transcribed Spacer (ITS) region of ribosomal DNA. 34 blood-engorged adult tsetse midguts were analyzed for blood meal sources by sequencing of the mitochondrial cytochrome c oxidase 1 (COI) and cytochrome b (cytb) genes. Results We captured a total of 622 Glossina fuscipes fuscipes tsetse flies (269 males and 353 females) in the two districts with apparent density (AD) ranging from 0.6 to 3.7 flies/trap/day (FTD). 10.7% (29/272) of the flies were infected with one or more trypanosome species. Infection rate was not significantly associated with district of origin (Generalized linear model (GLM), χ2 = 0.018, P = 0.895, df = 1, n = 272) and sex of the fly (χ2 = 1.723, P = 0.189, df = 1, n = 272). However, trypanosome infection was highly significantly associated with the fly’s age based on wing fray category (χ2 = 22.374, P < 0.001, df = 1, n = 272), being higher among the very old than the young tsetse. Nested PCR revealed several species of trypanosomes: T. vivax (6.62%), T. congolense (2.57%), T. brucei and T. simiae each at 0.73%. Blood meal analyses revealed five principal vertebrate hosts, namely, cattle (Bos taurus), humans (Homo sapiens), Nile monitor lizard (Varanus niloticus), African mud turtle (Pelusios chapini) and the African Savanna elephant (Loxodonta africana). Conclusion We found an infection rate of 10.8% in the tsetse sampled, with all infections attributed to trypanosome species that are causative agents for AAT. However, more verification of this finding using large-scale passive and active screening of human and tsetse samples should be done. Cattle and humans appear to be the most important tsetse hosts in the region and should be considered in the design of control interventions.
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Affiliation(s)
- Robert Opiro
- Department of Biology, Faculty of Science, Gulu University, P.O Box 166, Gulu, Uganda.
| | - Robert Opoke
- Department of Biology, Faculty of Science, Muni University, P.O Box 725, Arua, Uganda
| | - Harriet Angwech
- Department of Biology, Faculty of Science, Gulu University, P.O Box 166, Gulu, Uganda
| | - Esther Nakafu
- Department of Molecular Biology, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P.O Box 7062, Kampala, Uganda
| | - Francis A Oloya
- Department of Biology, Faculty of Science, Gulu University, P.O Box 166, Gulu, Uganda
| | - Geoffrey Openy
- Department of Biosystems Engineering, Faculty of Agriculture and Environment, Gulu University, P. O Box 166, Gulu, Uganda
| | - Moses Njahira
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub, P. O Box 30709, Nairobi, Kenya
| | - Mercy Macharia
- Biosciences Eastern and Central Africa-International Livestock Research Institute Hub, P. O Box 30709, Nairobi, Kenya
| | - Richard Echodu
- Department of Biology, Faculty of Science, Gulu University, P.O Box 166, Gulu, Uganda
| | - Geoffrey M Malinga
- Department of Biology, Faculty of Science, Gulu University, P.O Box 166, Gulu, Uganda.,Department of Forestry, Biodiversity and Tourism, Makerere University, PO Box 7062, Kampala, Uganda
| | - Elizabeth A Opiyo
- Department of Biology, Faculty of Science, Gulu University, P.O Box 166, Gulu, Uganda
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15
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Diskin C, Corcoran SE, Tyrrell VJ, McGettrick AF, Zaslona Z, O'Donnell VB, Nolan DP, O'Neill LAJ. The Trypanosome-Derived Metabolite Indole-3-Pyruvate Inhibits Prostaglandin Production in Macrophages by Targeting COX2. THE JOURNAL OF IMMUNOLOGY 2021; 207:2551-2560. [PMID: 34635586 DOI: 10.4049/jimmunol.2100402] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 09/09/2021] [Indexed: 11/19/2022]
Abstract
The protozoan parasite Trypanosoma brucei is the causative agent of the neglected tropical disease human African trypanosomiasis, otherwise known as sleeping sickness. Trypanosomes have evolved many immune-evasion mechanisms to facilitate their own survival, as well as prolonging host survival to ensure completion of the parasitic life cycle. A key feature of the bloodstream form of T. brucei is the secretion of aromatic keto acids, which are metabolized from tryptophan. In this study, we describe an immunomodulatory role for one of these keto acids, indole-3-pyruvate (I3P). We demonstrate that I3P inhibits the production of PGs in activated macrophages. We also show that, despite the reduction in downstream PGs, I3P augments the expression of cyclooxygenase (COX2). This increase in COX2 expression is mediated in part via inhibition of PGs relieving a negative-feedback loop on COX2. Activation of the aryl hydrocarbon receptor also participates in this effect. However, the increase in COX2 expression is of little functionality, as we also provide evidence to suggest that I3P targets COX activity. This study therefore details an evasion strategy by which a trypanosome-secreted metabolite potently inhibits macrophage-derived PGs, which might promote host and trypanosome survival.
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Affiliation(s)
- Ciana Diskin
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College, Dublin, Ireland; and
| | - Sarah E Corcoran
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College, Dublin, Ireland; and
| | - Victoria J Tyrrell
- Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Anne F McGettrick
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College, Dublin, Ireland; and
| | - Zbigniew Zaslona
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College, Dublin, Ireland; and
| | - Valerie B O'Donnell
- Systems Immunity Research Institute, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Derek P Nolan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College, Dublin, Ireland; and
| | - Luke A J O'Neill
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College, Dublin, Ireland; and
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16
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Volarić J, Szymanski W, Simeth NA, Feringa BL. Molecular photoswitches in aqueous environments. Chem Soc Rev 2021; 50:12377-12449. [PMID: 34590636 PMCID: PMC8591629 DOI: 10.1039/d0cs00547a] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Indexed: 12/17/2022]
Abstract
Molecular photoswitches enable dynamic control of processes with high spatiotemporal precision, using light as external stimulus, and hence are ideal tools for different research areas spanning from chemical biology to smart materials. Photoswitches are typically organic molecules that feature extended aromatic systems to make them responsive to (visible) light. However, this renders them inherently lipophilic, while water-solubility is of crucial importance to apply photoswitchable organic molecules in biological systems, like in the rapidly emerging field of photopharmacology. Several strategies for solubilizing organic molecules in water are known, but there are not yet clear rules for applying them to photoswitchable molecules. Importantly, rendering photoswitches water-soluble has a serious impact on both their photophysical and biological properties, which must be taken into consideration when designing new systems. Altogether, these aspects pose considerable challenges for successfully applying molecular photoswitches in aqueous systems, and in particular in biologically relevant media. In this review, we focus on fully water-soluble photoswitches, such as those used in biological environments, in both in vitro and in vivo studies. We discuss the design principles and prospects for water-soluble photoswitches to inspire and enable their future applications.
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Affiliation(s)
- Jana Volarić
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| | - Wiktor Szymanski
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
- Department of Radiology, Medical Imaging Center, University of Groningen, University Medical Centre Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Nadja A Simeth
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
- Institute for Organic and Biomolecular Chemistry, University of Göttingen, Tammannstr. 2, 37077 Göttingen, Germany
| | - Ben L Feringa
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
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Bessell PR, Esterhuizen J, Lehane MJ, Longbottom J, Mugenyi A, Selby R, Tirados I, Torr SJ, Waiswa C, Wamboga C, Hope A. Estimating the impact of Tiny Targets in reducing the incidence of Gambian sleeping sickness in the North-west Uganda focus. Parasit Vectors 2021; 14:410. [PMID: 34407867 PMCID: PMC8371857 DOI: 10.1186/s13071-021-04889-x] [Citation(s) in RCA: 3] [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: 03/29/2021] [Accepted: 07/22/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Riverine species of tsetse (Glossina) transmit Trypanosoma brucei gambiense, which causes Gambian human African trypanosomiasis (gHAT), a neglected tropical disease. Uganda aims to eliminate gHAT as a public health problem through detection and treatment of human cases and vector control. The latter is being achieved through the deployment of 'Tiny Targets', insecticide-impregnated panels of material which attract and kill tsetse. We analysed the spatial and temporal distribution of cases of gHAT in Uganda during the period 2010-2019 to assess whether Tiny Targets have had an impact on disease incidence. METHODS To quantify the deployment of Tiny Targets, we mapped the rivers and their associated watersheds in the intervention area. We then categorised each of these on a scale of 0-3 according to whether Tiny Targets were absent (0), present only in neighbouring watersheds (1), present in the watersheds but not all neighbours (2), or present in the watershed and all neighbours (3). We overlaid all cases that were diagnosed between 2000 and 2020 and assessed whether the probability of finding cases in a watershed changed following the deployment of targets. We also estimated the number of cases averted through tsetse control. RESULTS We found that following the deployment of Tiny Targets in a watershed, there were fewer cases of HAT, with a sampled error probability of 0.007. We estimate that during the intervention period 2012-2019 we should have expected 48 cases (95% confidence intervals = 40-57) compared to the 36 cases observed. The results are robust to a range of sensitivity analyses. CONCLUSIONS Tiny Targets have reduced the incidence of gHAT by 25% in north-western Uganda.
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Affiliation(s)
| | - Johan Esterhuizen
- Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, UK
| | - Michael J. Lehane
- Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, UK
| | - Joshua Longbottom
- Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, UK
| | - Albert Mugenyi
- Coordinating Office for Control of Trypanosomiasis in Uganda (COCTU), Kampala, Uganda
| | - Richard Selby
- Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, UK
| | - Inaki Tirados
- Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, UK
| | - Steve J. Torr
- Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, UK
| | - Charles Waiswa
- Coordinating Office for Control of Trypanosomiasis in Uganda (COCTU), Kampala, Uganda
| | | | - Andrew Hope
- Liverpool School of Tropical Medicine (LSTM), Pembroke Place, Liverpool, UK
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Longbottom J, Wamboga C, Bessell PR, Torr SJ, Stanton MC. Optimising passive surveillance of a neglected tropical disease in the era of elimination: A modelling study. PLoS Negl Trop Dis 2021; 15:e0008599. [PMID: 33651803 PMCID: PMC7954327 DOI: 10.1371/journal.pntd.0008599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 03/12/2021] [Accepted: 02/07/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Surveillance is an essential component of global programs to eliminate infectious diseases and avert epidemics of (re-)emerging diseases. As the numbers of cases decline, costs of treatment and control diminish but those for surveillance remain high even after the 'last' case. Reducing surveillance may risk missing persistent or (re-)emerging foci of disease. Here, we use a simulation-based approach to determine the minimal number of passive surveillance sites required to ensure maximum coverage of a population at-risk (PAR) of an infectious disease. METHODOLOGY AND PRINCIPAL FINDINGS For this study, we use Gambian human African trypanosomiasis (g-HAT) in north-western Uganda, a neglected tropical disease (NTD) which has been reduced to historically low levels (<1000 cases/year globally), as an example. To quantify travel time to diagnostic facilities, a proxy for surveillance coverage, we produced a high spatial-resolution resistance surface and performed cost-distance analyses. We simulated travel time for the PAR with different numbers (1-170) and locations (170,000 total placement combinations) of diagnostic facilities, quantifying the percentage of the PAR within 1h and 5h travel of the facilities, as per in-country targets. Our simulations indicate that a 70% reduction (51/170) in diagnostic centres still exceeded minimal targets of coverage even for remote populations, with >95% of a total PAR of ~3million individuals living ≤1h from a diagnostic centre, and we demonstrate an approach to best place these facilities, informing a minimal impact scale back. CONCLUSIONS Our results highlight that surveillance of g-HAT in north-western Uganda can be scaled back without substantially reducing coverage of the PAR. The methodology described can contribute to cost-effective and equable strategies for the surveillance of NTDs and other infectious diseases approaching elimination or (re-)emergence.
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Affiliation(s)
- Joshua Longbottom
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Health Informatics, Computing and Statistics, Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
- * E-mail:
| | | | | | - Steve J. Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michelle C. Stanton
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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Fetene E, Leta S, Regassa F, Büscher P. Global distribution, host range and prevalence of Trypanosoma vivax: a systematic review and meta-analysis. Parasit Vectors 2021; 14:80. [PMID: 33494807 PMCID: PMC7830052 DOI: 10.1186/s13071-021-04584-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 01/06/2021] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Trypanosomosis caused by Trypanosoma vivax is one of the diseases threatening the health and productivity of livestock in Africa and Latin America. Trypanosoma vivax is mainly transmitted by tsetse flies; however, the parasite has also acquired the ability to be transmitted mechanically by hematophagous dipterans. Understanding its distribution, host range and prevalence is a key step in local and global efforts to control the disease. METHODS The study was conducted according to the methodological recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. A systematic literature search was conducted on three search engines, namely PubMed, Scopus and CAB Direct, to identify all publications reporting natural infection of T. vivax across the world. All the three search engines were screened using the search term Trypanosoma vivax without time and language restrictions. Publications on T. vivax that met our inclusion criteria were considered for systematic review and meta-analysis. RESULT The study provides a global database of T. vivax, consisting of 899 records from 245 peer-reviewed articles in 41 countries. A total of 232, 6277 tests were performed on 97 different mammalian hosts, including a wide range of wild animals. Natural infections of T. vivax were recorded in 39 different African and Latin American countries and 47 mammalian host species. All the 245 articles were included into the qualitative analysis, while information from 186 cross-sectional studies was used in the quantitative analysis mainly to estimate the pooled prevalence. Pooled prevalence estimates of T. vivax in domestic buffalo, cattle, dog, dromedary camel, equine, pig, small ruminant and wild animals were 30.6%, 6.4%, 2.6%, 8.4%, 3.7%, 5.5%, 3.8% and 12.9%, respectively. Stratified according to the diagnostic method, the highest pooled prevalences were found with serological techniques in domesticated buffalo (57.6%) followed by equine (50.0%) and wild animals (49.3%). CONCLUSION The study provides a comprehensive dataset on the geographical distribution and host range of T. vivax and demonstrates the potential of this parasite to invade other countries out of Africa and Latin America.
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Affiliation(s)
- Eyerusalem Fetene
- College of Veterinary Medicine and Agriculture, Addis Ababa University, P. O. Box 34, Bishoftu, Ethiopia
| | - Samson Leta
- College of Veterinary Medicine and Agriculture, Addis Ababa University, P. O. Box 34, Bishoftu, Ethiopia.
| | - Fikru Regassa
- College of Veterinary Medicine and Agriculture, Addis Ababa University, P. O. Box 34, Bishoftu, Ethiopia.,FDRE Ministry of Agriculture, P.O.Box 62347/3735, Addia Ababa, Ethiopia
| | - Philippe Büscher
- Institute of Tropical Medicine, Department of Biomedical Sciences, Nationalestraat 155, 2000, Antwerp, Belgium
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Shereni W, Neves L, Argilés R, Nyakupinda L, Cecchi G. An atlas of tsetse and animal African trypanosomiasis in Zimbabwe. Parasit Vectors 2021; 14:50. [PMID: 33446276 PMCID: PMC7807824 DOI: 10.1186/s13071-020-04555-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 12/16/2020] [Indexed: 02/08/2023] Open
Abstract
Background In the 1980s and 1990s, great strides were taken towards the elimination of tsetse and animal African trypanosomiasis (AAT) in Zimbabwe. However, advances in recent years have been limited. Previously freed areas have been at risk of reinvasion, and the disease in tsetse-infested areas remains a constraint to food security. As part of ongoing control activities, monitoring of tsetse and AAT is performed regularly in the main areas at risk. However, a centralized digital archive is missing. To fill this gap, a spatially explicit, national-level database of tsetse and AAT (i.e. atlas) was established through systematic data collation, harmonization and geo-referencing for the period 2000–2019. Methods The atlas covers an area of approximately 70,000 km2, located mostly in the at-risk areas in the north of the country. In the tsetse component, a total of 33,872 entomological records were assembled for 4894 distinct trap locations. For the AAT component, 82,051 samples (mainly dry blood smears from clinically suspicious animals) were collected at 280 diptanks and examined for trypanosomal infection by microscopy. Results Glossina pallidipes (82.7% of the total catches) and Glossina morsitans morsitans (17.3%) were the two tsetse species recorded in the north and northwest parts of the country. No fly was captured in the northeast. The distribution of AAT follows broadly that of tsetse, although sporadic AAT cases were also reported from the northeast, apparently because of transboundary animal movement. Three trypanosome species were reported, namely Trypanosoma brucei (61.7% of recorded infections), Trypanosoma congolense (28.1%) and Trypanosoma vivax (10.2%). The respective prevalences, as estimated in sentinel herds by random sampling, were 2.22, 0.43 and 0.30%, respectively. Discussion The patterns of tsetse and AAT distributions in Zimbabwe are shaped by a combination of bioclimatic factors, historical events such as the rinderpest epizootic at the turn of the twentieth century and extensive and sustained tsetse control that is aimed at progressively eliminating tsetse and trypanosomiasis from the entire country. The comprehensive dataset assembled in the atlas will improve the spatial targeting of surveillance and control activities. It will also represent a valuable tool for research, by enabling large-scale geo-spatial analyses.![]()
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Affiliation(s)
- William Shereni
- Division of Tsetse Control Services, Ministry of Lands, Agriculture, Water and Rural Resettlement, Harare, Zimbabwe.
| | - Luis Neves
- Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa.,Centro de Biotecnlogia, Universidade Eduardo Mondlane, Maputo, Mozambique
| | - Rafael Argilés
- Joint Food and Agriculture Organization/International Atomic Energy Agency Programme, Vienna, Austria
| | - Learnmore Nyakupinda
- Division of Tsetse Control Services, Ministry of Lands, Agriculture, Water and Rural Resettlement, Harare, Zimbabwe
| | - Giuliano Cecchi
- Animal Production and Health Division, Food and Agriculture Organization of the United Nations, Rome, Italy
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21
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Münzker L, Petrick JK, Schleberger C, Clavel D, Cornaciu I, Wilcken R, Márquez JA, Klebe G, Marzinzik A, Jahnke W. Fragment-Based Discovery of Non-bisphosphonate Binders of Trypanosoma brucei Farnesyl Pyrophosphate Synthase. Chembiochem 2020; 21:3096-3111. [PMID: 32537808 DOI: 10.1002/cbic.202000246] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/29/2020] [Indexed: 12/26/2022]
Abstract
Trypanosoma brucei is the causative agent of human African trypanosomiasis (HAT). Nitrogen-containing bisphosphonates, a current treatment for bone diseases, have been shown to block the growth of the T. brucei parasites by inhibiting farnesyl pyrophosphate synthase (FPPS); however, due to their poor pharmacokinetic properties, they are not well suited for antiparasitic therapy. Recently, an allosteric binding pocket was discovered on human FPPS, but its existence on trypanosomal FPPS was unclear. We applied NMR and X-ray fragment screening to T. brucei FPPS and report herein on four fragments bound to this previously unknown allosteric site. Surprisingly, non-bisphosphonate active-site binders were also identified. Moreover, fragment screening revealed a number of additional binding sites. In an early structure-activity relationship (SAR) study, an analogue of an active-site binder was unexpectedly shown to bind to the allosteric site. Overlaying identified fragment binders of a parallel T. cruzi FPPS fragment screen with the T. brucei FPPS structure, and medicinal chemistry optimisation based on two binders revealed another example of fragment "pocket hopping". The discovery of binders with new chemotypes sets the framework for developing advanced compounds with pharmacokinetic properties suitable for the treatment of parasitic infections by inhibition of FPPS in T. brucei parasites.
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Affiliation(s)
- Lena Münzker
- Novartis Institutes for Biomedical Research Novartis Campus, 4002, Basel, Switzerland
| | - Joy Kristin Petrick
- Novartis Institutes for Biomedical Research Novartis Campus, 4002, Basel, Switzerland
| | - Christian Schleberger
- Novartis Institutes for Biomedical Research Novartis Campus, 4002, Basel, Switzerland
| | - Damien Clavel
- EMBL Grenoble, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, CEDEX 9, France
| | - Irina Cornaciu
- EMBL Grenoble, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, CEDEX 9, France.,ALPX, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, CEDEX 9, France
| | - Rainer Wilcken
- Novartis Institutes for Biomedical Research Novartis Campus, 4002, Basel, Switzerland
| | - José A Márquez
- EMBL Grenoble, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, CEDEX 9, France.,ALPX, 71 Avenue des Martyrs, CS 90181, 38042, Grenoble, CEDEX 9, France
| | - Gerhard Klebe
- Institut für Pharmazie, Philipps-Universität Marburg, Marbacher Weg 6, 35032, Marburg, Germany
| | - Andreas Marzinzik
- Novartis Institutes for Biomedical Research Novartis Campus, 4002, Basel, Switzerland
| | - Wolfgang Jahnke
- Novartis Institutes for Biomedical Research Novartis Campus, 4002, Basel, Switzerland
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22
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Longbottom J, Caminade C, Gibson HS, Weiss DJ, Torr S, Lord JS. Modelling the impact of climate change on the distribution and abundance of tsetse in Northern Zimbabwe. Parasit Vectors 2020; 13:526. [PMID: 33076987 PMCID: PMC7574501 DOI: 10.1186/s13071-020-04398-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 10/07/2020] [Indexed: 01/26/2023] Open
Abstract
Background Climate change is predicted to impact the transmission dynamics of vector-borne diseases. Tsetse flies (Glossina) transmit species of Trypanosoma that cause human and animal African trypanosomiasis. A previous modelling study showed that temperature increases between 1990 and 2017 can explain the observed decline in abundance of tsetse at a single site in the Mana Pools National Park of Zimbabwe. Here, we apply a mechanistic model of tsetse population dynamics to predict how increases in temperature may have changed the distribution and relative abundance of Glossina pallidipes across northern Zimbabwe. Methods Local weather station temperature measurements were previously used to fit the mechanistic model to longitudinal G. pallidipes catch data. To extend the use of the model, we converted MODIS land surface temperature to air temperature, compared the converted temperatures with available weather station data to confirm they aligned, and then re-fitted the mechanistic model using G. pallidipes catch data and air temperature estimates. We projected this fitted model across northern Zimbabwe, using simulations at a 1 km × 1 km spatial resolution, between 2000 to 2016. Results We produced estimates of relative changes in G. pallidipes mortality, larviposition, emergence rates and abundance, for northern Zimbabwe. Our model predicts decreasing tsetse populations within low elevation areas in response to increasing temperature trends during 2000–2016. Conversely, we show that high elevation areas (> 1000 m above sea level), previously considered too cold to sustain tsetse, may now be climatically suitable. Conclusions To our knowledge, the results of this research represent the first regional-scale assessment of temperature related tsetse population dynamics, and the first high spatial-resolution estimates of this metric for northern Zimbabwe. Our results suggest that tsetse abundance may have declined across much of the Zambezi Valley in response to changing climatic conditions during the study period. Future research including empirical studies is planned to improve model accuracy and validate predictions for other field sites in Zimbabwe.![]()
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Affiliation(s)
- Joshua Longbottom
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK. .,Centre for Health Informatics, Computing and Statistics, Lancaster Medical School, Lancaster University, Lancaster, UK.
| | - Cyril Caminade
- Department of Livestock and One Health, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Harry S Gibson
- Malaria Atlas Project, Big Data Institute, University of Oxford, Oxford, UK
| | - Daniel J Weiss
- Malaria Atlas Project, Big Data Institute, University of Oxford, Oxford, UK
| | - Steve Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jennifer S Lord
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
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23
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Rijo-Ferreira F, Takahashi JS. Sleeping Sickness: A Tale of Two Clocks. Front Cell Infect Microbiol 2020; 10:525097. [PMID: 33134186 PMCID: PMC7562814 DOI: 10.3389/fcimb.2020.525097] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 08/31/2020] [Indexed: 12/17/2022] Open
Abstract
Sleeping sickness is caused by a eukaryotic unicellular parasite known to infect wild animals, cattle, and humans. It causes a fatal disease that disrupts many rhythmic physiological processes, including daily rhythms of hormonal secretion, temperature regulation, and sleep, all of which are under circadian (24-h) control. In this review, we summarize research on sleeping sickness parasite biology and the impact it has on host health. We also consider the possible evolutionary advantages of sleep and circadian deregulation for the parasite.
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Affiliation(s)
- Filipa Rijo-Ferreira
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Joseph S Takahashi
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States.,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, United States
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24
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Tirados I, Hope A, Selby R, Mpembele F, Miaka EM, Boelaert M, Lehane MJ, Torr SJ, Stanton MC. Impact of tiny targets on Glossina fuscipes quanzensis, the primary vector of human African trypanosomiasis in the Democratic Republic of the Congo. PLoS Negl Trop Dis 2020; 14:e0008270. [PMID: 33064783 PMCID: PMC7608941 DOI: 10.1371/journal.pntd.0008270] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 11/03/2020] [Accepted: 08/26/2020] [Indexed: 11/18/2022] Open
Abstract
Over the past 20 years there has been a >95% reduction in the number of Gambian Human African trypanosomiasis (g-HAT) cases reported globally, largely as a result of large-scale active screening and treatment programmes. There are however still foci where the disease persists, particularly in parts of the Democratic Republic of the Congo (DRC). Additional control efforts such as tsetse control using Tiny Targets may therefore be required to achieve g-HAT elimination goals. The purpose of this study was to evaluate the impact of Tiny Targets within DRC. In 2015-2017, pre- and post-intervention tsetse abundance data were collected from 1,234 locations across three neighbouring Health Zones (Yasa Bonga, Mosango, Masi Manimba). Remotely sensed dry season data were combined with pre-intervention tsetse presence/absence data from 332 locations within a species distribution modelling framework to produce a habitat suitability map. The impact of Tiny Targets on the tsetse population was then evaluated by fitting a generalised linear mixed model to the relative fly abundance data collected from 889 post-intervention monitoring sites within Yasa Bonga, with habitat suitability, proximity to the intervention and intervention duration as covariates. Immediately following the introduction of the intervention, we observe a dramatic reduction in fly catches by > 85% (pre-intervention: 0.78 flies/trap/day, 95% CI 0.676-0.900; 3 month post-intervention: 0.11 flies/trap/day, 95% CI 0.070-0.153) which is sustained throughout the study period. Declines in catches were negatively associated with proximity to Tiny Targets, and while habitat suitability is positively associated with abundance its influence is reduced in the presence of the intervention. This study adds to the body of evidence demonstrating the impact of Tiny Targets on tsetse across a range of ecological settings, and further characterises the factors which modify its impact. The habitat suitability maps have the potential to guide the expansion of tsetse control activities in this area.
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Affiliation(s)
- Inaki Tirados
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Andrew Hope
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Richard Selby
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Fabrice Mpembele
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, Democratic Republic of the Congo
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, Democratic Republic of the Congo
| | - Marleen Boelaert
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Mike J. Lehane
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Steve J. Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michelle C. Stanton
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Health Informatics, Computing and Statistics, Lancaster Medical School, Lancaster University, United Kingdom
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Lemerani M, Jumah F, Bessell P, Biéler S, Ndung'u JM. Improved Access to Diagnostics for Rhodesian Sleeping Sickness around a Conservation Area in Malawi Results in Earlier Detection of Cases and Reduced Mortality. J Epidemiol Glob Health 2020; 10:280-287. [PMID: 32959623 PMCID: PMC7758844 DOI: 10.2991/jegh.k.200321.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/25/2020] [Indexed: 11/01/2022] Open
Abstract
Trypanosoma brucei rhodesiense Human African Trypanosomiasis (rHAT) is a zoonotic disease transmitted by tsetse flies from wild and domestic animals. It presents as an acute disease and advances rapidly into a neurological form that can only be treated with melarsoprol, which is associated with a high fatality rate. Bringing diagnostic services for rHAT closer to at-risk populations would increase chances of detecting cases in early stages of disease when treatment is safer and more effective. In Malawi, most of the rHAT cases occur around Vwaza Marsh Wildlife Reserve. Until 2013, diagnosis of rHAT in the region was only available at the Rumphi District Hospital that is more than 60 km away from the reserve. In 2013, Malawi's Ministry of Health initiated a project to enhance the detection of rHAT in five health facilities around Vwaza Marsh by upgrading laboratories and training technicians. We report here a retrospective study that was carried out to evaluate the impact of improving access to diagnostic services on the disease stage at diagnosis and on mortality. Between August 2014 and July 2017, 2014 patients suspected of having the disease were tested by microscopy, including 1267 who were tested in the new facilities. This resulted in the identification of 78 new rHAT cases, of which six died. Compared with previous years, data obtained during this period indicate that access to diagnostic services closer to where people at the greatest risk of infection live promotes identification of cases in earlier stages of infection, and improves treatment outcomes.
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Affiliation(s)
| | | | | | - Sylvain Biéler
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
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26
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Blood of African Hedgehog Atelerix albiventris Contains 115-kDa Trypanolytic Protein that Kills Trypanosoma congolense. Acta Parasitol 2020; 65:733-742. [PMID: 32385812 DOI: 10.2478/s11686-020-00211-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/01/2020] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Protozoan parasites of the Order Trypanosomatida infect a wide range of multicellular plants and animals, causing devastating and potentially fatal diseases. Trypanosomes are the most relevant members of the order in sub-Saharan Africa because of mortalities and morbidities caused to humans and livestock. PURPOSE There are growing concerns that trypanosomes are expanding their reservoirs among wild animals, which habours the parasites, withstand the infection, and from which tsetse flies transmit the parasites back to humans and livestock. This study was designed to investigate the potentials of the African hedgehog serving as reservoir for African animal trypanosomes. METHODS Five adult hedgehogs alongside five laboratory mice were intraperitoneally inoculated with 106 and 104 of Trypanosoma congolense cells, respectively, and monitored for parasitemia and survival. Serum from twenty hedgehogs was subjected to trypanocidal activity-guided fractionation by successive ion-exchange and gel-filtration chromatographies, followed by characterization with Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE). RESULTS Hedgehogs were resistant to the infection as no parasite was detected and none died even after 60 days, while all the mice died within 12 days. Both the serum and plasma prepared from hedgehogs demonstrated trypanocidal activity- rapidly killed trypanosomes even when diluted 1000 times. The trypanolytic factor was identified to be proteinaceous with an estimated molecular weight of 115-kDa. CONCLUSION For the first time, it is here demonstrated that hedgehog blood has significant trypanolytic activity against T. congolense. The potential application of the hedgehog protein for the breeding of trypanosomosis-resistant livestock in tsetse fly belt is discussed.
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Lyus R, Pollock A, Ocan M, Brhlikova P. Registration of antimicrobials, Kenya, Uganda and United Republic of Tanzania, 2018. Bull World Health Organ 2020; 98:530-538. [PMID: 32773898 PMCID: PMC7411312 DOI: 10.2471/blt.19.249433] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/06/2020] [Accepted: 05/14/2020] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To determine the proportion of essential and non-essential antimicrobial medicines that are registered on the drug registers in Kenya, Uganda and United Republic of Tanzania. METHODS We categorized all antimicrobials on the national drug registers and essential medicines lists of the three countries using the British National Formulary. We also categorized all antibiotics according to the World Health Organization access, watch and reserve (AWaRe) classification. We calculated the proportions of essential and non-essential antimicrobials that were registered by antimicrobial class and AWaRe classification. FINDINGS In 2018, Kenya had 2105 registered antimicrobials, Uganda had 1563 and the United Republic of Tanzania had 1327. Of these medicines, 1353 (64.3%) were non-essential in Kenya, 798 (51.1%) in Uganda and 706 (53.2%) in the United Republic of Tanzania. Kenya had 160 antimicrobials on its national essential medicines lists, Uganda had 187 and the United Republic of Tanzania had 182; of these, 33 (20.7%), 50 (26.7%) and 52 (28.6%) were not registered, respectively. High proportions of antimycobacterial and antiparasitic medicines were not registered. Of essential access antibiotics, 14.3% (4/28) were not registered in Kenya, 8.6% (3/35) in Uganda and 20.5% (8/39) in the United Republic of Tanzania, nor were 25.0% (3/12) of watch antibiotics in Kenya, 14.3% (2/14) in Uganda and 19.1% (4/21) in the United Republic of Tanzania. CONCLUSION Suboptimal registration of essential antimicrobials and over-registration of non-essential antimicrobials may encourage inappropriate use, especially since non-essential antimicrobials do not appear on national treatment guidelines. Countries should prioritize registration of the antimicrobial medicines on their essential medicines lists.
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Affiliation(s)
- Rosanna Lyus
- Centre for Regulatory Science, Population Health Sciences Institute, Baddiley-Clark Building, Newcastle University, Newcastle upon Tyne, NE2 4AX, England
| | - Allyson Pollock
- Centre for Regulatory Science, Population Health Sciences Institute, Baddiley-Clark Building, Newcastle University, Newcastle upon Tyne, NE2 4AX, England
| | - Moses Ocan
- Department of Pharmacology & Therapeutics, Makerere University, Kampala, Uganda
| | - Petra Brhlikova
- Centre for Regulatory Science, Population Health Sciences Institute, Baddiley-Clark Building, Newcastle University, Newcastle upon Tyne, NE2 4AX, England
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Marsela M, Hayashida K, Nakao R, Chatanga E, Gaithuma AK, Naoko K, Musaya J, Sugimoto C, Yamagishi J. Molecular identification of trypanosomes in cattle in Malawi using PCR methods and nanopore sequencing: epidemiological implications for the control of human and animal trypanosomiases. Parasite 2020; 27:46. [PMID: 32686644 PMCID: PMC7370688 DOI: 10.1051/parasite/2020043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 06/25/2020] [Indexed: 11/24/2022] Open
Abstract
This study aimed to identify trypanosomes infecting cattle in Malawi in order to understand the importance of cattle in the transmission dynamics of Human African Trypanosomiasis (HAT) and Animal African Trypanosomosis (AAT). A total of 446 DNA samples from cattle blood from three regions of Malawi were screened for African trypanosomes by ITS1 PCR. The obtained amplicons were sequenced using a portable next-generation sequencer, MinION, for validation. Comparison of the results from ITS1 PCR and MinION sequencing showed that combining the two methods provided more accurate species identification than ITS1 PCR alone. Further PCR screening targeting the serum resistance-associated (SRA) gene was conducted to detect Trypanosoma brucei rhodesiense. Trypanosoma congolense was the most prevalent Trypanosoma sp., which was found in Nkhotakota (10.8%; 20 of 185), followed by Kasungu (2.5%; 5 of 199). Of note, the prevalence of T. b. rhodesiense detected by SRA PCR was high in Kasungu and Nkhotakota showing 9.5% (19 of 199) and 2.7% (5 of 185), respectively. We report the presence of animal African trypanosomes and T. b. rhodesiense from cattle at the human-livestock-wildlife interface for the first time in Malawi. Our results confirmed that animal trypanosomes are important causes of anemia in cattle and that cattle are potential reservoirs for human African trypanosomiasis in Malawi.
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Affiliation(s)
- Megasari Marsela
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Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University Kita-20, Nishi-10, Kita-ku Sapporo 001-0020 Hokkaido Japan
| | - Kyoko Hayashida
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Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University Kita-20, Nishi-10, Kita-ku Sapporo 001-0020 Hokkaido Japan
| | - Ryo Nakao
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Laboratory of Parasitology, Veterinary Medicine Faculty, Hokkaido University Kita-18, Nishi-9, Kita-ku Sapporo 060-0818 Hokkaido Japan
| | - Elisha Chatanga
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Laboratory of Parasitology, Veterinary Medicine Faculty, Hokkaido University Kita-18, Nishi-9, Kita-ku Sapporo 060-0818 Hokkaido Japan
| | - Alex Kiarie Gaithuma
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Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University Kita-20, Nishi-10, Kita-ku Sapporo 001-0020 Hokkaido Japan
| | - Kawai Naoko
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Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University Kita-20, Nishi-10, Kita-ku Sapporo 001-0020 Hokkaido Japan
| | - Janelisa Musaya
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Department of Pathology, College of Medicine, University of Malawi P/Bag 360 Chichiri 30096 Blantyre 3 Malawi
| | - Chihiro Sugimoto
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Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University Kita-20, Nishi-10, Kita-ku Sapporo 001-0020 Hokkaido Japan
| | - Junya Yamagishi
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Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University Kita-20, Nishi-10, Kita-ku Sapporo 001-0020 Hokkaido Japan
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International Collaboration Unit, Research Center for Zoonosis Control, Hokkaido University Kita-20, Nishi-10, Kita-ku Sapporo 001-0020 Hokkaido Japan
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Castaño MS, Aliee M, Mwamba Miaka E, Keeling MJ, Chitnis N, Rock KS. Screening Strategies for a Sustainable Endpoint for Gambiense Sleeping Sickness. J Infect Dis 2020; 221:S539-S545. [PMID: 31876949 PMCID: PMC7289553 DOI: 10.1093/infdis/jiz588] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Gambiense human African trypanosomiasis ([gHAT] sleeping sickness) is a vector-borne disease that is typically fatal without treatment. Intensified, mainly medical-based, interventions in endemic areas have reduced the occurrence of gHAT to historically low levels. However, persistent regions, primarily in the Democratic Republic of Congo (DRC), remain a challenge to achieving the World Health Organization's goal of global elimination of transmission (EOT). METHODS We used stochastic models of gHAT transmission fitted to DRC case data and explored patterns of regional reporting and extinction. The time to EOT at a health zone scale (~100 000 people) and how an absence of reported cases informs about EOT was quantified. RESULTS Regional epidemiology and level of active screening (AS) both influenced the predicted time to EOT. Different AS cessation criteria had similar expected infection dynamics, and recrudescence of infection was unlikely. However, whether EOT has been achieved when AS ends is critically dependent on the stopping criteria. Two or three consecutive years of no detected cases provided greater confidence of EOT compared with a single year (~66%-75% and ~82%-84% probability of EOT, respectively, compared with 31%-51%). CONCLUSIONS Multiple years of AS without case detections is a valuable measure to assess the likelihood that the EOT target has been met locally.
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Affiliation(s)
- M Soledad Castaño
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Maryam Aliee
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Coventry, United Kingdom
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine, Kinshasa, the Democratic Republic of the Congo
| | - Matt J Keeling
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Coventry, United Kingdom
- School of Life Science, University of Warwick, Coventry, United Kingdom
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Kat S Rock
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research (SBIDER), University of Warwick, Coventry, United Kingdom
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Ngari NN, Gamba DO, Olet PA, Zhao W, Paone M, Cecchi G. Developing a national atlas to support the progressive control of tsetse-transmitted animal trypanosomosis in Kenya. Parasit Vectors 2020; 13:286. [PMID: 32503681 PMCID: PMC7275614 DOI: 10.1186/s13071-020-04156-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/28/2020] [Indexed: 11/30/2022] Open
Abstract
Background African animal trypanosomosis (AAT) is a major livestock disease in Kenya. Even though, over the years various organizations have collected a vast amount of field data on tsetse and AAT in different parts of the country, recent national-level maps are lacking. To address this gap, a national atlas of tsetse and AAT distribution is being developed by the Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC) and partners. Methods All data collected by KENTTEC from 2006 to 2019 were systematically assembled, georeferenced and harmonized. A comprehensive data repository and a spatially-explicit database were created. Input data were collected mainly in the context of control activities, and include both baseline surveys (i.e. pre-intervention) and the subsequent monitoring during and after interventions. Surveys were carried out in four regions (i.e. Western, Rift Valley, Central and Coast), and in 21 of the 47 counties in Kenya. Various devices were used for entomological data collection (i.e. biconical, NGU and H traps, and sticky panels), while the buffy-coat technique was the method used to detect AAT. Results Tsetse trapping was carried out in approximately 5000 locations, and flies (> 71,000) were caught in all four investigated regions. Six species of Glossina were detected: G. pallidipes (87% of the catches); G. brevipalpis (8%); G. fuscipes fuscipes (4%); G. longipennis (< 1%); G. austeni (< 1%); and G. swynnertoni (< 1%). A total of 49,785 animals (98% of which cattle) were tested for AAT in approximately 500 locations. Of these, 914 animals were found to be infected. AAT was confirmed in all study regions, in particular caused by Trypanosoma vivax (48% of infections) and T. congolense (42%). Fewer cases of T. brucei were found. Conclusions The development and regular update of a comprehensive national database of tsetse and AAT is crucial to guide decision making for the progressive control of the disease. This first version of the atlas based on KENTTEC data has achieved a remarkable level of geographical coverage, but temporal and spatial gaps still exist. Other stakeholders at the national and international level will contribute to the initiative, thus improving the completeness of the atlas. ![]()
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Affiliation(s)
- Nancy N Ngari
- Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC), Nairobi, Kenya
| | - Daniel O Gamba
- Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC), Nairobi, Kenya
| | - Pamela A Olet
- Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC), Nairobi, Kenya
| | - Weining Zhao
- Food and Agriculture Organization of the United Nations (FAO), Animal Production and Health Division, Rome, Italy
| | - Massimo Paone
- Food and Agriculture Organization of the United Nations (FAO), Animal Production and Health Division, Rome, Italy
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations (FAO), Animal Production and Health Division, Rome, Italy.
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Pilotte N, Cook DA, Pryce J, Zulch MF, Minetti C, Reimer LJ, Williams SA. Laboratory evaluation of molecular xenomonitoring using mosquito and tsetse fly excreta/feces to amplify Plasmodium, Brugia, and Trypanosoma DNA. Gates Open Res 2020; 3:1734. [PMID: 32596646 PMCID: PMC7308644 DOI: 10.12688/gatesopenres.13093.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2020] [Indexed: 11/20/2022] Open
Abstract
Background: Results from an increasing number of studies suggest that mosquito excreta/feces (E/F) testing has considerable potential to serve as a supplement for traditional molecular xenomonitoring techniques. However, as the catalogue of possible use-cases for this methodology expands, and the list of amenable pathogens grows, a number of fundamental methods-based questions remain. Answering these questions is critical to maximizing the utility of this approach and to facilitating its successful implementation as an effective tool for molecular xenomonitoring. Methods: Utilizing E/F produced by mosquitoes or tsetse flies experimentally exposed to Brugia malayi, Plasmodium falciparum, or Trypanosoma brucei brucei, factors such as limits of detection, throughput of testing, adaptability to use with competent and incompetent vector species, and effects of additional blood feedings post parasite-exposure were evaluated. Two platforms for the detection of pathogen signal (quantitative real-time PCR and digital PCR (dPCR)) were also compared, with strengths and weaknesses examined for each. Results: Experimental results indicated that high throughput testing is possible when evaluating mosquito E/F for the presence of either B. malayi or P. falciparum from both competent and incompetent vector mosquito species. Furthermore, following exposure to pathogen, providing mosquitoes with a second, uninfected bloodmeal did not expand the temporal window for E/F collection during which pathogen detection was possible. However, this collection window did appear longer in E/F collected from tsetse flies following exposure to T. b. brucei. Testing also suggested that dPCR may facilitate detection through its increased sensitivity. Unfortunately, logistical obstacles will likely make the large-scale use of dPCR impractical for this purpose. Conclusions: By examining many E/F testing variables, expansion of this technology to a field-ready platform has become increasingly feasible. However, translation of this methodology from the lab to the field will first require field-based pilot studies aimed at assessing the efficacy of E/F screening.
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Affiliation(s)
- Nils Pilotte
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, 01063, USA
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts, 01003, USA
| | - Darren A.N. Cook
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Joseph Pryce
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Michael F. Zulch
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, 01063, USA
| | - Corrado Minetti
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Lisa J. Reimer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Steven A. Williams
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, 01063, USA
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts, 01003, USA
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Franco JR, Cecchi G, Priotto G, Paone M, Diarra A, Grout L, Simarro PP, Zhao W, Argaw D. Monitoring the elimination of human African trypanosomiasis at continental and country level: Update to 2018. PLoS Negl Trop Dis 2020; 14:e0008261. [PMID: 32437391 PMCID: PMC7241700 DOI: 10.1371/journal.pntd.0008261] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/30/2020] [Indexed: 11/18/2022] Open
Abstract
Background In 2012 human African trypanosomiasis (HAT), also known as sleeping sickness, was targeted for elimination as a public health problem, set to be achieved by 2020. The World Health Organization (WHO) provides here the 2018 update on the progress made toward that objective. Global indicators are reviewed, in particular the number of reported cases and the areas at risk. Recently developed indicators for the validation of HAT elimination at the national level are also presented. Methodology/Principal Findings With 977 cases reported in 2018, down from 2,164 in 2016, the main global indicator of elimination is already well within the 2020 target (i.e. 2,000 cases). Areas at moderate or higher risk (i.e. ≥ 1 case/10,000 people/year) are also steadily shrinking (less than 200,000 km2 in the period 2014–2018), thus nearing the 2020 target [i.e. 90% reduction (638,000 km2) from the 2000–2004 baseline (709,000 km2)]. Health facilities providing diagnosis and treatment of gambiense HAT continued to increase (+7% since the previous survey), with a better coverage of at-risk populations. By contrast, rhodesiense HAT health facilities decreased in number (-10.5%) and coverage. At the national level, eight countries meet the requirements to request validation of gambiense HAT elimination as a public health problem (i.e. Benin, Burkina Faso, Cameroon, Côte d’Ivoire, Ghana, Mali, Rwanda, and Togo), while for other endemic countries more efforts are needed in surveillance, control, or both. Conclusions/Significance The 2020 goal of HAT elimination as a public health problem is within grasp, and eligible countries are encouraged to request validation of their elimination status. Beyond 2020, the HAT community must gear up for the elimination of gambiense HAT transmission (2030 goal), by preparing for both the expected challenges (e.g. funding, coordination, integration of HAT control into regular health systems, development of more adapted tools, cryptic trypanosome reservoirs, etc.) and the unexpected ones. Human African trypanosomiasis (HAT), a lethal disease transmitted by tsetse flies, wreaked havoc in Africa at different times in the 20th century. Over the past twenty years, huge efforts made by a broad coalition of stakeholders curbed the last epidemic and brought the disease to the brink of elimination. In this paper, the latest figures on disease occurrence, geographical distribution and control activities are presented. Strong evidence indicates that the elimination of sleeping sickness ‘as a public health problem’ by 2020 is well within reach. In particular, fewer than one thousand new cases were reported in 2018, and the area where the risk of infection is estimated as moderate, high or very high has shrunk to less than 200,000 km2. More than half of this area is in the Democratic Republic of the Congo. The interruption of transmission of the gambiense form, targeted by the World Health Organization (WHO) for 2030, will require renewed efforts to tackle a range of expected and unexpected challenges. The rhodesiense form of the disease represents a small part of the overall HAT burden. For this form, the problem of under detection is on the rise and, because of an important animal reservoir, the elimination of disease transmission is not envisioned at this stage.
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Affiliation(s)
- José R. Franco
- World Health Organization, Control of Neglected Tropical Diseases, Geneva, Switzerland
- * E-mail:
| | - 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, 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, Communicable Disease Unit, Brazzaville, Congo
| | - Lise Grout
- World Health Organization, Control of Neglected Tropical Diseases, Geneva, Switzerland
| | - Pere P. Simarro
- Consultant World Health Organization, Control of Neglected Tropical Diseases, 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, Geneva, Switzerland
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O'Hagan MP, Peñalver P, Gibson RSL, Morales JC, Galan MC. Stiff-Stilbene Ligands Target G-Quadruplex DNA and Exhibit Selective Anticancer and Antiparasitic Activity. Chemistry 2020; 26:6224-6233. [PMID: 32030823 PMCID: PMC7318697 DOI: 10.1002/chem.201905753] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Indexed: 12/16/2022]
Abstract
G-quadruplex nucleic acid structures have long been studied as anticancer targets whilst their potential in antiparasitic therapy has only recently been recognized and barely explored. Herein, we report the synthesis, biophysical characterization, and in vitro screening of a series of stiff-stilbene G4 binding ligands featuring different electronics, side-chain chemistries, and molecular geometries. The ligands display selectivity for G4 DNA over duplex DNA and exhibit nanomolar toxicity against Trypasanoma brucei and HeLa cancer cells whilst remaining up to two orders of magnitude less toxic to non-tumoral mammalian cell line MRC-5. Our study demonstrates that stiff-stilbenes show exciting potential as the basis of selective anticancer and antiparasitic therapies. To achieve the most efficient G4 recognition the scaffold must possess the optimal electronics, substitution pattern and correct molecular configuration.
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Affiliation(s)
| | - Pablo Peñalver
- Instituto de Parasitología y Biomedicina “López Neyra”Consejo Superior de Investigaciones Científicas (CSIC)PTS Granada, Avenida del Conocimiento 1718016Armilla, GranadaSpain
| | | | - Juan C. Morales
- Instituto de Parasitología y Biomedicina “López Neyra”Consejo Superior de Investigaciones Científicas (CSIC)PTS Granada, Avenida del Conocimiento 1718016Armilla, GranadaSpain
| | - M. Carmen Galan
- School of ChemistryUniversity of BristolCantock's CloseBristolBS8 1TSUK
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Insights from quantitative and mathematical modelling on the proposed 2030 goal for gambiense human African trypanosomiasis (gHAT). Gates Open Res 2020; 3:1553. [PMID: 32411945 PMCID: PMC7193711 DOI: 10.12688/gatesopenres.13070.2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/06/2020] [Indexed: 11/20/2022] Open
Abstract
Gambiense human African trypanosomiasis (gHAT) is a parasitic, vector-borne neglected tropical disease that has historically affected populations across West and Central Africa and can result in death if untreated. Following from the success of recent intervention programmes against gHAT, the World Health Organization (WHO) has defined a 2030 goal of global elimination of transmission (EOT). The key proposed indicator to measure achievement of the goal is zero reported cases. Results of previous mathematical modelling and quantitative analyses are brought together to explore both the implications of the proposed indicator and the feasibility of achieving the WHO goal. Whilst the indicator of zero case reporting is clear and measurable, it is an imperfect proxy for EOT and could arise either before or after EOT is achieved. Lagging reporting of infection and imperfect diagnostic specificity could result in case reporting after EOT, whereas the converse could be true due to underreporting, lack of coverage, and cryptic human and animal reservoirs. At the village-scale, the WHO recommendation of continuing active screening until there are three years of zero cases yields a high probability of local EOT, but extrapolating this result to larger spatial scales is complex. Predictive modelling of gHAT has consistently found that EOT by 2030 is unlikely across key endemic regions if current medical-only strategies are not bolstered by improved coverage, reduced time to detection and/or complementary vector control. Unfortunately, projected costs for strategies expected to meet EOT are high in the short term and strategies that are cost-effective in reducing burden are unlikely to result in EOT by 2030. Future modelling work should aim to provide predictions while taking into account uncertainties in stochastic dynamics and infection reservoirs, as well as assessment of multiple spatial scales, reactive strategies, and measurable proxies of EOT.
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Lumbala C, Matovu E, Sendagire H, Kazibwe AJN, Likwela JL, Muhindo Mavoko H, Kayembe S, Lutumba P, Biéler S, Van Geertruyden JP, Ndung’u JM. Performance evaluation of a prototype rapid diagnostic test for combined detection of gambiense human African trypanosomiasis and malaria. PLoS Negl Trop Dis 2020; 14:e0008168. [PMID: 32251426 PMCID: PMC7162526 DOI: 10.1371/journal.pntd.0008168] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 04/16/2020] [Accepted: 02/24/2020] [Indexed: 11/18/2022] Open
Abstract
Background Malaria is endemic in all regions where gambiense or rhodesiense human African trypanosomiasis (HAT) is reported, and both diseases have similarities in their symptomatology. A combined test could be useful for both diseases and would facilitate integration of the screening for gambiense HAT (gHAT) and malaria diagnosis. This study aimed to evaluate a combined prototype rapid diagnostic test (RDT) for gHAT and malaria. Methods Blood samples were collected in the Democratic Republic of the Congo and in Uganda to evaluate the performance of a prototype HAT/Malaria Combined RDT in comparison to an individual malaria RDT based on Plasmodium falciparum (P.f.) Histidine Rich Protein II (HRP-II or HRP2) antigen (SD BIOLINE Malaria Ag P.f. RDT) for malaria detection and an individual gHAT RDT based on recombinant antigens, the SD BIOLINE HAT 2.0 RDT for HAT screening. Due to the current low prevalence of gHAT in endemic regions, the set of blood samples that were collected was used to evaluate the specificity of the RDTs for gHAT, and additional archived plasma samples were used to complete the evaluation of the HAT/Malaria Combined RDT in comparison to the HAT 2.0 RDT. Results Frozen whole blood samples from a total of 486 malaria cases and 239 non-malaria controls, as well as archived plasma samples from 246 gHAT positive and 246 gHAT negative individuals were tested. For malaria, the sensitivity and specificity of the malaria band in the HAT/Malaria Combined RDT were 96.9% (95% CI: 95.0–98.3) and 97.1% (95% CI: 94.1–98.8) respectively. The sensitivity and specificity of the SD BIOLINE malaria Ag P.f. RDT were 97.3% (95% CI: 95.5–98.6) and 97.1% (95% CI: 94.1–98.8) respectively. For gHAT, using archived plasma samples, the sensitivity and specificity were respectively 89% (95% CI: 84.4–92.6) and 93.5% (95% CI: 89.7–96.2) with the HAT/Malaria Combined RDT, and 88.2% (95% CI: 83.5–92) and 94.7% (95% CI: 91.1–97.2) with the HAT 2.0 RDT. Using the whole blood samples that were collected during the study, the specificity of the HAT/Malaria Combined RDT for gHAT was 95.8% (95% CI: 94.3–97.0). Conclusion The HAT/Malaria Combined prototype RDT was as accurate as the individual malaria or gHAT RDTs. The HAT/Malaria Combined prototype RDT is therefore suitable for both malaria diagnosis and gHAT screening. However, there is a need to assess its accuracy using fresh samples in prospective clinical trials. The annual number of reported cases of human African trypanosomiasis (HAT), also known as sleeping sickness (SS), is currently below 1,000 cases worldwide. The Democratic Republic of the Congo (DRC), the most affected country, and Uganda, which shares a border with DRC, are both endemic for gambiense HAT (gHAT). The main strategy to control gHAT is screening of at-risk individuals, followed by diagnosis and treatment of confirmed cases. However, this strategy and even the passive screening as currently implemented become less efficient with declining incidence, justifying innovative strategies to efficiently detect the remaining cases. All areas where gHAT occurs are also endemic for malaria, presenting an opportunity to integrate gHAT screening activities within malaria control activities. This integration is warranted by the fact that in early disease stage, gHAT patients present with signs and symptoms strikingly similar to those of malaria. In order to use malaria diagnosis as an entry point to screen for gHAT, Standard Diagnostics (SD), Republic of Korea (now Abbott Diagnostics, Korea Inc–ADK) made a Combined prototype RDT for both malaria and gHAT, expected to be as accurate as the individual gHAT and malaria RDTs. In this study, we evaluated the accuracy of the Combined prototype RDT using whole blood samples collected in Uganda and DRC, and archived plasma samples collected in DRC, Angola and Central African Republic. We found that the Combined prototype performs just as well as individual RDTs.
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Affiliation(s)
- Crispin Lumbala
- Disease Control Directorate, Ministry of Public Health, Democratic Republic of the Congo
- Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
- * E-mail:
| | - Enock Matovu
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Hakim Sendagire
- College of Health Sciences, Makerere University, Kampala, Uganda
| | - Anne J. N. Kazibwe
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Joris L. Likwela
- Public Health Department, Faculty of Medicine and Pharmacy, University of Kisangani, Kisangani, Democratic Republic of the Congo
| | | | - Simon Kayembe
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | - Pascal Lutumba
- Kinshasa University, Kinshasa, Democratic Republic of the Congo
| | - Sylvain Biéler
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | | | - Joseph M. Ndung’u
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
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de Gier J, Cecchi G, Paone M, Dede P, Zhao W. The continental atlas of tsetse and African animal trypanosomosis in Nigeria. Acta Trop 2020; 204:105328. [PMID: 31904345 DOI: 10.1016/j.actatropica.2020.105328] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/04/2019] [Accepted: 01/01/2020] [Indexed: 10/25/2022]
Abstract
Tsetse-transmitted trypanosomosis remains a major animal health problem in Nigeria, in a context where changes in land cover, climate and control interventions are modifying its epidemiological patterns. Evidence-based decision making for the progressive control of the disease requires spatially-explicit information on its occurrence and prevalence, as well as on the distribution and abundance of the tsetse vector. In the framework of the continental Atlas of tsetse and African animal trypanosomosis (AAT), a geo-referenced database was assembled for Nigeria, based on the systematic review of 133 scientific publications (period January 1990 - March 2019). The three main species of trypanosomes responsible for the disease (i.e. Trypanosoma vivax, T. congolense and T. brucei) were found to be widespread, thus posing a national-level problem. Their geographic distribution extends beyond the tsetse-infested belt, owing to the combined effect of animal movement and mechanical transmission by non-tsetse vectors. T. simiae, the major trypanosomal pathogen in pigs, T. godfreyi and the human-infective T. brucei gambiense were also reported. AAT was reported in a number of susceptible host species, including cattle, sheep, goats, pigs, camels, horses, donkeys and dogs, while no study on wildlife was identified. Estimates of prevalence are heavily influenced by the sensitivity of the diagnostic techniques, ranging from an average of 3.5% for blood films to 31.0% for molecular techniques. Two riverine tsetse species (i.e. Glossina palpalis palpalis and G. tachinoides) were found to have the broadest geographical range, as they were detected in all six geopolitical zones of Nigeria. By contrast, the distribution of savannah species (i.e. G. morsitans submorsitans and G. longipalpis) appears to be highly fragmented, and limited to protected areas. Very little information is available for forest species, with one single paper reporting on G. fusca congolensis and G. nigrofusca nigrofusca in the Niger Delta region. The future development of a national Atlas of tsetse and AAT, relying on both published and unpublished information, could improve on the present review and provide further epidemiological evidence for decision making.
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Mulenga P, Chenge F, Boelaert M, Mukalay A, Lutumba P, Lumbala C, Luboya O, Coppieters Y. Integration of Human African Trypanosomiasis Control Activities into Primary Healthcare Services: A Scoping Review. Am J Trop Med Hyg 2020; 101:1114-1125. [PMID: 31482788 PMCID: PMC6838596 DOI: 10.4269/ajtmh.19-0232] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Human African trypanosomiasis (HAT) also known as sleeping sickness is targeted for elimination as a public health problem by 2020 and elimination of infection by 2030. Although the number of reported cases is decreasing globally, integration of HAT control activities into primary healthcare services is endorsed to expand surveillance and control. However, this integration process faces several challenges in the field. This literature review analyzes what is known about integrated HAT control to guide the integration process in an era of HAT elimination. We carried out a scoping review by searching PubMed and Google Scholar data bases as well as gray literature documents resulting in 25 documents included for analysis. The main reasons in favor to integrate HAT control were related to coverage, cost, quality of service, or sustainability. There were three categories of factors influencing the integration process: 1) the clinical evolution of HAT, 2) the organization of health services, and 3) the diagnostic and therapeutic tools. There is a consensus that both active and passive approaches to HAT case detection and surveillance need to be combined, in a context-sensitive way. However, apart from some documentation about the constraints faced by local health services, there is little evidence on how this synergy is best achieved.
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Affiliation(s)
- Philippe Mulenga
- School of Public Health, Université Libre de Bruxelles (ULB), Brussels, Belgium.,Faculty of Medicine and School of Public Health, University of Lubumbashi, Lubumbashi, Democratic Republic of the Congo.,Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Faustin Chenge
- Centre de Connaissances en Santé en République Démocratique du Congo, Kinshasa, Democratic Republic of the Congo.,Faculty of Medicine and School of Public Health, University of Lubumbashi, Lubumbashi, Democratic Republic of the Congo
| | - Marleen Boelaert
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Abdon Mukalay
- Faculty of Medicine and School of Public Health, University of Lubumbashi, Lubumbashi, Democratic Republic of the Congo
| | - Pascal Lutumba
- Department of Tropical Medicine, Faculty of Medicine, University of Kinshasa, Kinshasa, Democratic Republic of the Congo
| | - Crispin Lumbala
- National Program for the Control of Human African Trypanosomiasis, Kinshasa, Democratic Republic of the Congo
| | - Oscar Luboya
- Faculty of Medicine and School of Public Health, University of Lubumbashi, Lubumbashi, Democratic Republic of the Congo
| | - Yves Coppieters
- School of Public Health, Université Libre de Bruxelles (ULB), Brussels, Belgium
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Fofana M, Mitri C, Diallo D, Rotureau B, Diagne CT, Gaye A, Ba Y, Dieme C, Diallo M, Dia I. Possible influence of Plasmodium/Trypanosoma co-infections on the vectorial capacity of Anopheles mosquitoes. BMC Res Notes 2020; 13:127. [PMID: 32131895 PMCID: PMC7057563 DOI: 10.1186/s13104-020-04977-8] [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: 01/29/2020] [Accepted: 02/25/2020] [Indexed: 11/16/2022] Open
Abstract
Objective In tropical Africa, trypanosomiasis is present in endemic areas with many other diseases including malaria. Because malaria vectors become more anthropo-zoophilic under the current insecticide pressure, they may be exposed to trypanosome parasites. By collecting mosquitoes in six study sites with distinct malaria infection prevalence and blood sample from cattle, we tried to assess the influence of malaria-trypanosomiasis co-endemicity on the vectorial capacity of Anopheles. Results Overall, all animal infections were due to Trypanosoma vivax (infection rates from 2.6 to 10.5%) in villages where the lowest Plasmodium prevalence were observed at the beginning of the study. An. gambiae s.l. displayed trophic preferences for human-animal hosts. Over 84 mosquitoes, only one was infected by Plasmodium falciparum (infection rate: 4.5%) in a site that displayed the highest prevalence at the beginning of the study. Thus, Anopheles could be exposed to Trypanosoma when they feed on infected animals. No Plasmodium infection was observed in the Trypanosoma-infected animals sites. This can be due to an interaction between both parasites as observed in mice and highlights the need of further studies considering Trypanosoma/Plasmodium mixed infections to better characterize the role of these infections in the dynamic of malaria transmission and the mechanisms involved.
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Affiliation(s)
- Maty Fofana
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Sénégal
| | - Christian Mitri
- Unité Génétique et Génomique des Insectes Vecteurs, Institut Pasteur, Paris, France
| | - Diawo Diallo
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Sénégal
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201 & Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Cheikh Tidiane Diagne
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Sénégal
| | - Alioune Gaye
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Sénégal
| | - Yamar Ba
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Sénégal
| | - Constentin Dieme
- Unité Génétique et Génomique des Insectes Vecteurs, Institut Pasteur, Paris, France.,Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Mawlouth Diallo
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Sénégal
| | - Ibrahima Dia
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, BP 220, Dakar, Sénégal.
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Longbottom J, Krause A, Torr SJ, Stanton MC. Quantifying geographic accessibility to improve efficiency of entomological monitoring. PLoS Negl Trop Dis 2020; 14:e0008096. [PMID: 32203517 PMCID: PMC7117774 DOI: 10.1371/journal.pntd.0008096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 04/02/2020] [Accepted: 01/28/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Vector-borne diseases are important causes of mortality and morbidity in humans and livestock, particularly for poorer communities and countries in the tropics. Large-scale programs against these diseases, for example malaria, dengue and African trypanosomiasis, include vector control, and assessing the impact of this intervention requires frequent and extensive monitoring of disease vector abundance. Such monitoring can be expensive, especially in the later stages of a successful program where numbers of vectors and cases are low. METHODOLOGY/PRINCIPAL FINDINGS We developed a system that allows the identification of monitoring sites where pre-intervention densities of vectors are predicted to be high, and travel cost to sites is low, highlighting the most efficient locations for longitudinal monitoring. Using remotely sensed imagery and an image classification algorithm, we mapped landscape resistance associated with on- and off-road travel for every gridded location (3m and 0.5m grid cells) within Koboko district, Uganda. We combine the accessibility surface with pre-existing estimates of tsetse abundance and propose a stratified sampling approach to determine the most efficient locations for longitudinal data collection. Our modelled predictions were validated against empirical measurements of travel-time and existing maps of road networks. We applied this approach in northern Uganda where a large-scale vector control program is being implemented to control human African trypanosomiasis, a neglected tropical disease (NTD) caused by trypanosomes transmitted by tsetse flies. Our accessibility surfaces indicate a high performance when compared to empirical data, with remote sensing identifying a further ~70% of roads than existing networks. CONCLUSIONS/SIGNIFICANCE By integrating such estimates with predictions of tsetse abundance, we propose a methodology to determine the optimal placement of sentinel monitoring sites for evaluating control programme efficacy, moving from a nuanced, ad-hoc approach incorporating intuition, knowledge of vector ecology and local knowledge of geographic accessibility, to a reproducible, quantifiable one.
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Affiliation(s)
- Joshua Longbottom
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Health Informatics, Computing and Statistics, Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - Ana Krause
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Stephen J. Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michelle C. Stanton
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Centre for Health Informatics, Computing and Statistics, Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
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Neau P, Hänel H, Lameyre V, Strub-Wourgaft N, Kuykens L. Innovative Partnerships for the Elimination of Human African Trypanosomiasis and the Development of Fexinidazole. Trop Med Infect Dis 2020; 5:tropicalmed5010017. [PMID: 32012658 PMCID: PMC7157581 DOI: 10.3390/tropicalmed5010017] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/08/2020] [Accepted: 01/10/2020] [Indexed: 11/27/2022] Open
Abstract
Human African Trypanosomiasis (HAT or sleeping sickness) is a life-threatening neglected tropical disease that is endemic in 36 sub-Saharan African countries. Until recently, treatment options were limited and hampered by unsatisfactory efficacy, toxicity, and long and cumbersome administration regimens, compounded by infrastructure inadequacies in the remote rural regions worst affected by the disease. Increased funding and awareness of HAT over the past two decades has led to a steady decline in reported cases (<1000 in 2018). Recent drug development strategies have resulted in development of the first all-oral treatment for HAT, fexinidazole. Fexinidazole received European Medicines Agency positive scientific opinion in 2018 and is now incorporated into the WHO interim guidelines as one of the first-line treatments for HAT, allowing lumbar puncture to become non-systematic. Here, we highlight the role of global collaborations in the effort to control HAT and develop new treatments. The long-standing collaboration between the WHO, Sanofi and the Drugs for Neglected Diseases initiative (Geneva, Switzerland) was instrumental for achieving the control and treatment development goals in HAT, whilst at the same time ensuring that efforts were led by national authorities and control programs to leave a legacy of highly trained healthcare workers and improved research and health infrastructure.
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Affiliation(s)
- Philippe Neau
- Sanofi France, 82 avenue Raspail, 94250 Gentilly, France;
- Correspondence:
| | - Heinz Hänel
- Sanofi Deutschland, Industriepark Höchst, Bldg. H831, 65926 Frankfurt am Main, Germany;
| | | | - Nathalie Strub-Wourgaft
- Drugs for Neglected Diseases initiative (DNDi), 15 Chemin Louis-Dunant, 1202 Geneva, Switzerland;
| | - Luc Kuykens
- Sanofi US, 55 Corporate Drive, Bridgewater, NJ 08807, USA;
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Falisse JB, Mwamba-Miaka E, Mpanya A. Whose Elimination? Frontline Workers' Perspectives on the Elimination of the Human African Trypanosomiasis and Its Anticipated Consequences. Trop Med Infect Dis 2020; 5:tropicalmed5010006. [PMID: 31906341 PMCID: PMC7157216 DOI: 10.3390/tropicalmed5010006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 12/20/2019] [Accepted: 12/25/2019] [Indexed: 01/06/2023] Open
Abstract
While academic literature has paid careful attention to the technological efforts―drugs, tests, and tools for vector control―deployed to eliminate Gambiense Human African Trypanosomiasis (HAT), the human resources and health systems dimensions of elimination are less documented. This paper analyses the perspectives and experiences of frontline nurses, technicians, and coordinators who work for the HAT programme in the former province of Bandundu in the Democratic Republic of the Congo, at the epidemic’s very heart. The research is based on 21 semi-structured interviews conducted with frontline workers in February 2018. The results highlight distinctive HAT careers as well as social elevation through specialised work. Frontline workers are concerned about changes in active screening strategies and the continued existence of the vector, which lead them to question the possibility of imminent elimination. Managers seem to anticipate a post-HAT situation and prepare for the employment of their staff; most workers see their future relatively confidently, as re-allocated to non-vertical units. The findings suggest concrete pathways for improving the effectiveness of elimination efforts: improving active screening through renewed engagements with local leaders, conceptualising horizontal integration in terms of human resources mobility, and investing more in detection and treatment activities (besides innovation).
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Affiliation(s)
- Jean-Benoît Falisse
- Centre of African Studies, University of Edinburgh, Edinburgh EH8 9LD, UK
- Correspondence: ; Tel.: +44-131-651-1632
| | - Erick Mwamba-Miaka
- Programme National de lutte contre la THA (PNLTHA), Kinshasa 2, Democratic Republic of the Congo; (E.M.-M.); (A.M.)
| | - Alain Mpanya
- Programme National de lutte contre la THA (PNLTHA), Kinshasa 2, Democratic Republic of the Congo; (E.M.-M.); (A.M.)
- Faculté des Sciences de la Santé, Université Pedagogique Nationale (UPN), Kinshasa BP 8815, Democratic Republic of the Congo
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Pilotte N, Cook DA, Pryce J, Zulch MF, Minetti C, Reimer LJ, Williams SA. Laboratory evaluation of molecular xenomonitoring using mosquito excreta/feces to amplify Plasmodium, Brugia, and Trypanosoma DNA. Gates Open Res 2019; 3:1734. [PMID: 32596646 PMCID: PMC7308644 DOI: 10.12688/gatesopenres.13093.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2019] [Indexed: 03/30/2024] Open
Abstract
Background: Results from an increasing number of studies suggest that mosquito excreta/feces (E/F) testing has considerable potential to serve as a supplement for traditional molecular xenomonitoring techniques. However, as the catalogue of possible use-cases for this methodology expands, and the list of amenable pathogens grows, a number of fundamental methods-based questions remain. Answering these questions is critical to maximizing the utility of this approach and to facilitating its successful implementation as an effective tool for molecular xenomonitoring. Methods: Utilizing E/F produced by mosquitoes or tsetse flies experimentally exposed to Brugia malayi, Plasmodium falciparum, or Trypanosoma brucei brucei, factors such as limits of detection, throughput of testing, adaptability to use with competent- and incompetent-vector species, and effects of additional blood feedings post parasite-exposure were evaluated. Two platforms for the detection of pathogen signal (quantitative real-time PCR and digital PCR [dPCR]) were also compared, with strengths and weaknesses examined for each. Results: Experimental results indicated that high throughput testing is possible when evaluating mosquito E/F for the presence of either B. malayi or P. falciparum from both competent- and incompetent-vector mosquito species. Furthermore, following exposure to pathogen, providing mosquitoes with a second, uninfected bloodmeal did not expand the temporal window for E/F collection during which pathogen detection was possible. However, this collection window did appear longer in E/F collected from tsetse flies following exposure to T. b. brucei. Testing also suggested that dPCR may facilitate detection through its increased sensitivity. Unfortunately, logistical obstacles will likely make the large-scale use of dPCR impractical for this purpose. Conclusions: By examining many E/F testing variables, expansion of this technology to a field-ready platform has become increasingly feasible. However, translation of this methodology from the lab to the field will first require the completion of field-based pilot studies aimed at assessing the efficacy of E/F screening.
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Affiliation(s)
- Nils Pilotte
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, 01063, USA
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts, 01003, USA
| | - Darren A.N. Cook
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Joseph Pryce
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Michael F. Zulch
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, 01063, USA
| | - Corrado Minetti
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Lisa J. Reimer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Steven A. Williams
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, 01063, USA
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts, 01003, USA
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Grau-Pujol B, Massangaie M, Cano J, Maroto C, Ndeve A, Saute F, Muñoz J. Frequency and distribution of neglected tropical diseases in Mozambique: a systematic review. Infect Dis Poverty 2019; 8:103. [PMID: 31836025 PMCID: PMC6909500 DOI: 10.1186/s40249-019-0613-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/20/2019] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Neglected tropical diseases (NTDs) affect more than one billion people living in vulnerable conditions. In spite of initiatives recently contributing to fill NTDs gaps on national and local prevalence and distribution, more epidemiological data are still needed for effective control and elimination interventions. MAIN TEXT Mozambique is considered one of the countries with highest NTDs burden although available data is scarce. This study aims to conduct a systematic review on published available data about the burden and distribution of the different NTDs across Mozambique since January 1950 until December 2018. We identified manuscripts from electronic databases (Pubmed, EmBase and Global Health) and paper publications and grey literature from Mozambique Ministry of Health. Manuscripts fulfilling inclusion criteria were: cross-sectional studies, ecological studies, cohorts, reports, systematic reviews, and narrative reviews capturing epidemiological information of endemic NTDs in Mozambique. Case-control studies, letters to editor, case reports and case series of imported cases were excluded. A total of 466 manuscripts were initially identified and 98 were finally included after the revision following PRISMA guidelines. Eleven NTDs were reported in Mozambique during the study span. Northern provinces (Nampula, Cabo Delgado, Niassa, Tete and Zambezia) and Maputo province had the higher number of NTDs detected. Every disease had their own report profile: while schistosomiasis have been continuously reported since 1952 until nowadays, onchocerciasis and cysticercosis last available data is from 2007 and Echinococcosis have never been evaluated in the country. Thus, both space and time gaps on NTDs epidemiology have been identified. CONCLUSIONS This review assembles NTDs burden and distribution in Mozambique. Thus, contributes to the understanding of NTDs epidemiology in Mozambique and highlights knowledge gaps. Hence, the study provides key elements to progress towards the control and interruption of transmission of these diseases in the country.
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Affiliation(s)
- Berta Grau-Pujol
- ISGlobal, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.
- Centro de Investigação em Saúde da Manhiça (CISM), Maputo, Mozambique.
- Mundo Sano Foundation, Buenos Aires, Argentina.
| | - Marilia Massangaie
- Direcção Nacional de Saúde Pública, Ministério da Saúde, Maputo, Mozambique
| | - Jorge Cano
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Carmen Maroto
- Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Francisco Saute
- Centro de Investigação em Saúde da Manhiça (CISM), Maputo, Mozambique
| | - Jose Muñoz
- ISGlobal, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
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Ndeffo-Mbah ML, Pandey A, Atkins KE, Aksoy S, Galvani AP. The impact of vector migration on the effectiveness of strategies to control gambiense human African trypanosomiasis. PLoS Negl Trop Dis 2019; 13:e0007903. [PMID: 31805051 PMCID: PMC6894748 DOI: 10.1371/journal.pntd.0007903] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 11/04/2019] [Indexed: 02/06/2023] Open
Abstract
Background Several modeling studies have been undertaken to assess the feasibility of the WHO goal of eliminating gambiense human African trypanosomiasis (g-HAT) by 2030. However, these studies have generally overlooked the effect of vector migration on disease transmission and control. Here, we evaluated the impact of vector migration on the feasibility of interrupting transmission in different g-HAT foci. Methods We developed a g-HAT transmission model of a single tsetse population cluster that accounts for migration of tsetse fly into this population. We used a model calibration approach to constrain g-HAT incidence to ranges expected for high, moderate and low transmission settings, respectively. We used the model to evaluate the effectiveness of current intervention measures, including medical intervention through enhanced screening and treatment, and vector control, for interrupting g-HAT transmission in disease foci under each transmission setting. Results We showed that, in low transmission settings, under enhanced medical intervention alone, at least 70% treatment coverage is needed to interrupt g-HAT transmission within 10 years. In moderate transmission settings, a combination of medical intervention and a vector control measure with a daily tsetse mortality greater than 0.03 is required to achieve interruption of disease transmission within 10 years. In high transmission settings, interruption of disease transmission within 10 years requires a combination of at least 70% medical intervention coverage and at least 0.05 tsetse daily mortality rate from vector control. However, the probability of achieving elimination in high transmission settings decreases with an increased tsetse migration rate. Conclusion Our results suggest that the WHO 2030 goal of G-HAT elimination is, at least in theory, achievable. But the presence of tsetse migration may reduce the probability of interrupting g-HAT transmission in moderate and high transmission foci. Therefore, optimal vector control programs should incorporate monitoring and controlling of vector density in buffer areas around foci of g-HAT control efforts. Gambian human African trypanosomiasis (g-HAT), also known as sleeping sickness, is a vector-borne parasitic disease transmitted by tsetse flies. If untreated, g-HAT infection will usually result in death. Recently, the World Health Organization (WHO) has targeted g-HAT for elimination through achieving interruption of transmission by 2030. To help inform elimination efforts, mathematical models have been used to evaluate the feasibility of the WHO goals in different g-HAT transmission foci. However, these mathematical models have generally ignored the role that tsetse migration may have in the spread and reemergence of g-HAT. Using a mathematical model, we evaluate the impact of tsetse migration on the effectiveness of current intervention measures for achieving interruption of g-HAT transmission in different transmission foci. We consider different interventions such as enhanced screening and treatment and vector control. We show that vector control has a great potential for reducing transmission. Still, the presence and intensity of tsetse migration can undermine its effectiveness for interrupting disease transmission, especially in high transmission foci. Our results indicate the need of accounting for tsetse surveillance and migration data in designing vector control efforts for g-HAT elimination.
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Affiliation(s)
- Martial L. Ndeffo-Mbah
- Department of Veterinary Integrative Biosciences, Texas A&M College of Veterinary Medicine and Biomedical Sciences, College Station, TX, United States of America
- Department of Epidemiology and Biostatistics, Texas A&M School of Public Health, College Station, TX, United States of America
- * E-mail:
| | - Abhishek Pandey
- Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, CT, United States of America
- Department of Epidemiology and Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America
| | - Katherine E. Atkins
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Global Health, The Usher Institute for Population Health Sciences and Informatics, Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Serap Aksoy
- Department of Epidemiology and Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America
| | - Alison P. Galvani
- Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, CT, United States of America
- Department of Epidemiology and Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America
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Modeling antimalarial and antihuman African trypanosomiasis compounds: a ligand- and structure-based approaches. Mol Divers 2019; 24:1107-1124. [PMID: 31760561 DOI: 10.1007/s11030-019-10015-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/06/2019] [Indexed: 02/07/2023]
Abstract
This study examines the interaction of 137 antimalarial and antihuman African trypanosomiasis compounds [bis(2-aminoimidazolines), bisguanidinediphenyls and polyamines] on three different in vitro assays (Trypanosoma brucei rhodesiense (T.b.r.), Plasmodium falciparum (P.f.) and cytotoxicity-L6 cells). ΔTm values, wherever available, were also examined for the considered ligands. Eight DNA-ligand complexes and one DNA structure without ligand were selected from protein data bank (PDB) based on the structural similarity. Geometry optimization of all the considered ligands was carried out at the B3LYP/6-31G(d) level of theory. The AutoDock4 tool was utilized for the docking of these molecules at the minor groove of nine selected DNA crystal structures. We observed DT20, DA6, DT8 and DT19 residues generally interact with most of the considered ligands. Molecular dynamics simulations, molecular mechanics-generalized born surface area and molecular mechanics-Poisson Boltzmann surface area calculations indicate that the docked poses are generally stable and docked ligands do not show much deviation in the minor groove of DNA until 10 ns simulation. Efficient and statistically significant quantitative structure-activity relationship models for T.b.r., P.f., C-L6 and ΔTm values were developed. All the generated models are internally and externally validated. We predicted a few ligands with significant IC50 values against P.f. based on the developed models. These results may help to design new and potent antimalarial and antihuman African trypanosomal compounds.
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Rock KS, Ndeffo-Mbah ML, Castaño S, Palmer C, Pandey A, Atkins KE, Ndung'u JM, Hollingsworth TD, Galvani A, Bever C, Chitnis N, Keeling MJ. Assessing Strategies Against Gambiense Sleeping Sickness Through Mathematical Modeling. Clin Infect Dis 2019; 66:S286-S292. [PMID: 29860287 PMCID: PMC5982708 DOI: 10.1093/cid/ciy018] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Background Control of gambiense sleeping sickness relies predominantly on passive and active screening of people, followed by treatment. Methods Mathematical modeling explores the potential of 3 complementary interventions in high- and low-transmission settings. Results Intervention strategies that included vector control are predicted to halt transmission most quickly. Targeted active screening, with better and more focused coverage, and enhanced passive surveillance, with improved access to diagnosis and treatment, are both estimated to avert many new infections but, when used alone, are unlikely to halt transmission before 2030 in high-risk settings. Conclusions There was general model consensus in the ranking of the 3 complementary interventions studied, although with discrepancies between the quantitative predictions due to differing epidemiological assumptions within the models. While these predictions provide generic insights into improving control, the most effective strategy in any situation depends on the specific epidemiology in the region and the associated costs.
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Affiliation(s)
- Kat S Rock
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Coventry, United Kingdom.,School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | | | - Soledad Castaño
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Switzerland.,University of Basel, Switzerland
| | - Cody Palmer
- Institute of Disease Modeling, Bellevue, Washington
| | - Abhishek Pandey
- Yale School of Public Health, Yale University, New Haven, Connecticut
| | - Katherine E Atkins
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, United Kingdom.,Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | | | - T Déirdre Hollingsworth
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Coventry, United Kingdom.,School of Life Sciences, University of Warwick, Coventry, United Kingdom.,Mathematics Institute, University of Warwick, Coventry, United Kingdom
| | - Alison Galvani
- Yale School of Public Health, Yale University, New Haven, Connecticut
| | | | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Switzerland.,University of Basel, Switzerland
| | - Matt J Keeling
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, Coventry, United Kingdom.,School of Life Sciences, University of Warwick, Coventry, United Kingdom.,Mathematics Institute, University of Warwick, Coventry, United Kingdom
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Davis CN, Rock KS, Mwamba Miaka E, Keeling MJ. Village-scale persistence and elimination of gambiense human African trypanosomiasis. PLoS Negl Trop Dis 2019; 13:e0007838. [PMID: 31658269 PMCID: PMC6837580 DOI: 10.1371/journal.pntd.0007838] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 11/07/2019] [Accepted: 10/10/2019] [Indexed: 11/18/2022] Open
Abstract
Gambiense human African trypanosomiasis (gHAT) is one of several neglected tropical diseases that is targeted for elimination by the World Health Organization. Recent years have seen a substantial decline in the number of globally reported cases, largely driven by an intensive process of screening and treatment. However, this infection is highly focal, continuing to persist at low prevalence even in small populations. Regional elimination, and ultimately global eradication, rests on understanding the dynamics and persistence of this infection at the local population scale. Here we develop a stochastic model of gHAT dynamics, which is underpinned by screening and reporting data from one of the highest gHAT incidence regions, Kwilu Province, in the Democratic Republic of Congo. We use this model to explore the persistence of gHAT in villages of different population sizes and subject to different patterns of screening. Our models demonstrate that infection is expected to persist for long periods even in relatively small isolated populations. We further use the model to assess the risk of recrudescence following local elimination and consider how failing to detect cases during active screening events informs the probability of elimination. These quantitative results provide insights for public health policy in the region, particularly highlighting the difficulties in achieving and measuring the 2030 elimination goal.
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Affiliation(s)
- Christopher N. Davis
- MathSys CDT, Mathematics Institute, University of Warwick, Coventry, United Kingdom
- Zeeman Institute (SBIDER), University of Warwick, Coventry, United Kingdom
| | - Kat S. Rock
- Zeeman Institute (SBIDER), University of Warwick, Coventry, United Kingdom
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
| | - Erick Mwamba Miaka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), Ave Coisement Liberation et Bd Triomphal No 1, Commune de Kasavubu, Kinshasa, Demecratic Republic of the Congo
| | - Matt J. Keeling
- Zeeman Institute (SBIDER), University of Warwick, Coventry, United Kingdom
- Mathematics Institute, University of Warwick, Coventry, United Kingdom
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- * E-mail:
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Insights from quantitative and mathematical modelling on the proposed 2030 goal for gambiense human African trypanosomiasis (gHAT). Gates Open Res 2019; 3:1553. [PMID: 32411945 PMCID: PMC7193711 DOI: 10.12688/gatesopenres.13070.1] [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] [Accepted: 10/02/2019] [Indexed: 03/29/2024] Open
Abstract
Gambiense human African trypanosomiasis (gHAT) is a parasitic, vector-borne neglected tropical disease that has historically affected populations across West and Central Africa and can result in death if untreated. Following from the success of recent intervention programmes against gHAT, the World Health Organization (WHO) has defined a 2030 goal of global elimination of transmission (EOT). The key proposed indicator to measure achievement of the goal is to have zero reported cases. Results of previous mathematical modelling and quantitative analyses are brought together to explore both the implications of the proposed indicator and the feasibility of achieving the WHO goal. Whilst the indicator of zero case reporting is clear and measurable, it is an imperfect proxy for EOT and could arise either before or after EOT is achieved. Lagging reporting of infection and imperfect diagnostic specificity could result in case reporting after EOT, whereas the converse could be true due to underreporting, lack of coverage, and cryptic human and animal reservoirs. At the village-scale, the WHO recommendation of continuing active screening until there are three years of zero cases yields a high probability of local EOT, but extrapolating this result to larger spatial scales is complex. Predictive modelling of gHAT has consistently found that EOT by 2030 is unlikely across key endemic regions if current medical-only strategies are not bolstered by improved coverage, reduced time to detection and/or complementary vector control. Unfortunately, projected costs for strategies expected to meet EOT are high in the short term and strategies that are cost-effective in reducing burden are unlikely to result in EOT by 2030. Future modelling work should aim to provide predictions while taking into account uncertainties in stochastic dynamics and infection reservoirs, as well as assessment of multiple spatial scales, reactive strategies, and measurable proxies of EOT.
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Selby R, Wamboga C, Erphas O, Mugenyi A, Jamonneau V, Waiswa C, Torr SJ, Lehane M. Gambian human African trypanosomiasis in North West Uganda. Are we on course for the 2020 target? PLoS Negl Trop Dis 2019; 13:e0007550. [PMID: 31412035 PMCID: PMC6693741 DOI: 10.1371/journal.pntd.0007550] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 06/13/2019] [Indexed: 01/28/2023] Open
Abstract
In 1994, combined active and passive screening reported 1469 cases from the historic Gambian Human African Trypanosomiasis (gHAT) foci of West Nile, Uganda. Since 2011 systematic active screening has stopped and there has been reliance on passive screening. During 2014, passive screening alone detected just nine cases. In the same year a tsetse control intervention was expanded to cover the main gHAT foci in West Nile to curtail transmission of gHAT contributing to the elimination of gHAT as a public health problem in the area. It is known that sole reliance on passive screening is slow to detect cases and can underestimate the actual true number. We therefore undertook an active screening programme designed to test the efficacy of these interventions against gHAT transmission and clarify disease status. Screening was conducted in 28 randomly selected villages throughout the study area, aiming to sample all residents. Whole blood from 10,963 participants was analysed using CATT and 97 CATT suspects (0.9%) were evaluated with microscopy and trypanolysis. No confirmed cases were found providing evidence that the gHAT prevention programmes in West Nile have been effective. Results confirm gHAT prevalence in the study area of West Nile is below the elimination threshold (1 new case / 10,000 population), making elimination on course across this study area if status is maintained. The findings of this study can be used to guide future HAT and tsetse management in other gHAT foci, where reduced caseloads necessitate a shift from active to passive screening. The number of gHAT cases across West Nile, Uganda has declined in the last 20 years. This decline is due to the impact of programmes of active and passive case detection and treatment which have recently been combined with tsetse control operations (post 2011). We carried out an active survey of gHAT to evaluate the prevalence in areas where vector control has been introduced. Our results confirm that the overall prevalence of gHAT is below 1 case per 10,000 people at risk in the historical foci and shows that results from passive screening are providing an accurate picture of gHAT prevalence in the area.
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Affiliation(s)
- Richard Selby
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
- * E-mail:
| | - Charles Wamboga
- Vector Control Division, Ministry of Health, Wandegeya, Kampala, Uganda
| | - Olema Erphas
- Vector Control Division, Ministry of Health, Wandegeya, Kampala, Uganda
| | - Albert Mugenyi
- Co-ordinating Office for Control of Trypanosomiasis Uganda, Wandegeya, Kampala, Uganda
| | - Vincent Jamonneau
- UMR 177 Intertryp, Institut de Recherche pour le Développement (IRD), Montpellier, France
| | - Charles Waiswa
- Co-ordinating Office for Control of Trypanosomiasis Uganda, Wandegeya, Kampala, Uganda
| | - Steve J. Torr
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Michael Lehane
- Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
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Dattani A, Wilkinson SR. Deciphering the interstrand crosslink DNA repair network expressed by Trypanosoma brucei. DNA Repair (Amst) 2019; 78:154-166. [DOI: 10.1016/j.dnarep.2019.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/29/2019] [Accepted: 04/24/2019] [Indexed: 10/26/2022]
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