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Lacey C, Musa A, Khalil ET, Younis B, Osman M, Wiggins R, Keding A, Kaye P. LEISH2b - A phase 2b study to assess the safety, efficacy, and immunogenicity of the Leishmania vaccine ChAd63-KH in post-kala azar dermal leishmaniasis. Wellcome Open Res 2022; 7:200. [PMID: 37252616 PMCID: PMC10213822 DOI: 10.12688/wellcomeopenres.17951.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2022] [Indexed: 01/16/2024] Open
Abstract
Background: The leishmaniases are neglected tropical diseases caused by various Leishmania parasite species transmitted by sand flies. They comprise a number of systemic and cutaneous syndromes including kala-azar (visceral leishmaniasis, VL), cutaneous leishmaniasis (CL), and post-kala-azar dermal leishmaniasis (PKDL). The leishmaniases cause significant mortality (estimated 20 - 50,000 deaths annually), morbidity, psychological sequelae, and healthcare and societal costs. Treatment modalities remain difficult. E.g., East African PKDL requires 20 days of intravenous therapy, and frequently relapsing VL is seen in the setting of HIV and immunodeficiency. We developed a new therapeutic vaccine, ChAd63-KH for VL / CL / PKDL and showed it to be safe and immunogenic in a phase 1 trial in the UK, and in a phase 2a trial in PKDL patients in Sudan. Methods: This is a randomised double-blind placebo-controlled phase 2b trial to assess the therapeutic efficacy and safety of ChAd63-KH in patients with persistent PKDL in Sudan. 100 participants will be randomly assigned 1:1 to receive placebo or ChAd63-KH (7.5 x10 10vp i.m.) at a single time point. Follow up is for 120 days after dosing and we will compare the clinical evolution of PKDL, as well as the humoral and cellular immune responses between the two arms. Discussion: Successful development of a therapeutic vaccine for leishmaniasis would have wide-ranging direct and indirect healthcare benefits that could be realized rapidly. For PKDL patients, an effective therapeutic vaccination used alone would have very significant clinical value, reducing the need for extensive hospitalization and chemotherapy. Combining vaccine with drug (immuno-chemotherapy) might significantly increase the effective life of new drugs, with lower dose / abbreviated regimens helping to limit the emergence of drug resistance. If therapeutic benefit of ChAd63-KH can be shown in PKDL further evaluation of the vaccine in other forms of leishmaniasis should be considered. Clinicaltrials.gov registration: NCT03969134.
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Affiliation(s)
- Charles Lacey
- York Biomedical Research Institute, University of York, UK, York, UK
| | - Ahmed Musa
- Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - El Tahir Khalil
- Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Brima Younis
- Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Mohamed Osman
- York Biomedical Research Institute, University of York, UK, York, UK
| | - Rebecca Wiggins
- York Biomedical Research Institute, University of York, UK, York, UK
| | - Ada Keding
- York Trials Unit, University of York, UK, York, UK
| | - Paul Kaye
- York Biomedical Research Institute, University of York, UK, York, UK
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Grifferty G, Shirley H, McGloin J, Kahn J, Orriols A, Wamai R. Vulnerabilities to and the Socioeconomic and Psychosocial Impacts of the Leishmaniases: A Review. Res Rep Trop Med 2021; 12:135-151. [PMID: 34188584 PMCID: PMC8236266 DOI: 10.2147/rrtm.s278138] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/06/2021] [Indexed: 11/23/2022] Open
Abstract
The leishmaniases are a group of four vector-borne neglected tropical diseases (NTDs) with 1.6 billion people in some 100 countries at risk. They occur in certain eco-epidemiological foci that reflect manipulation by human activities, such as migration, urbanization and deforestation, of which poverty, conflict and climate change are key drivers. Given their synergistic impacts, risk factors and the vulnerabilities of poor populations and the launch of a new 2030 roadmap for NTDs in the context of the global sustainability agenda, it is warranted to update the state of knowledge of the leishmaniases and their effects. Using existing literature, we review socioeconomic and psychosocial impacts of leishmaniasis within a framework of risk factors and vulnerabilities to help inform policy interventions. Studies show that poverty is an overarching primary risk factor. Low-income status fosters inadequate housing, malnutrition and lack of sanitation, which create and exacerbate complexities in access to care and treatment outcomes as well as education and awareness. The co-occurrence of the leishmaniases with malnutrition and HIV infection further complicate diagnosis and treatment, leading to poor diagnostic outcomes and therapeutic response. Even with free treatment, households may suffer catastrophic health expenditure from direct and indirect medical costs, which compounds existing financial strain in low-income communities for households and healthcare systems. The dermatological presentations of the leishmaniases may result in long-term severe disfigurement, leading to stigmatization, reduced quality of life, discrimination and mental health issues. A substantial amount of recent literature points to the vulnerability pathways and burden of leishmaniasis on women, in particular, who disproportionately suffer from these impacts. These emerging foci demonstrate a need for continued international efforts to address key risk factors and population vulnerabilities if leishmaniasis control, and ultimately elimination, is to be achieved by 2030.
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Affiliation(s)
- Grace Grifferty
- Department of Biology, Northeastern University, College of Science, Boston, MA, USA
| | - Hugh Shirley
- Department of Biochemistry, Northeastern University, College of Science, Boston, MA, USA.,Program in Medical Education, Harvard Medical School, Boston, MA, USA
| | - Jamie McGloin
- Department of Health Sciences, Northeastern University, Bouvé College of Health Sciences, Boston, MA, USA
| | - Jorja Kahn
- Department of Behavioral Neuroscience, Northeastern University, College of Science, Boston, MA, USA
| | - Adrienne Orriols
- Department of Behavioral Neuroscience, Northeastern University, College of Science, Boston, MA, USA
| | - Richard Wamai
- Department of Cultures, Societies and Global Studies, Northeastern University, College of Social Sciences and Humanities, Integrated Initiative for Global Health, Boston, MA, USA
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Fortunato AK, Glasser CP, Watson JA, Lu Y, Rychtář J, Taylor D. Mathematical modelling of the use of insecticide-treated nets for elimination of visceral leishmaniasis in Bihar, India. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201960. [PMID: 34234949 PMCID: PMC8242840 DOI: 10.1098/rsos.201960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 05/24/2021] [Indexed: 05/27/2023]
Abstract
Visceral leishmaniasis (VL) is a deadly neglected tropical disease caused by a parasite Leishmania donovani and spread by female sand flies Phlebotomus argentipes. There is conflicting evidence regarding the role of insecticide-treated nets (ITNs) on the prevention of VL. Numerous studies demonstrated the effectiveness of ITNs. However, KalaNet, a large trial in Nepal and India did not support those findings. The purpose of this paper is to gain insight into the situation by mathematical modelling. We expand a mathematical model of VL transmission based on the KalaNet trial and incorporate the use of ITNs explicitly into the model. One of the major contributions of this work is that we calibrate the model based on the available epidemiological data, generally independent of the KalaNet trial. We validate the model on data collected during the KalaNet trial. We conclude that in order to eliminate VL, the ITN usage would have to stay above 96%. This is higher than the 91% ITNs use at the end of the trial which may explain why the trial did not show a positive effect from ITNs. At the same time, our model indicates that asymptomatic individuals play a crucial role in VL transmission.
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Affiliation(s)
- Anna K. Fortunato
- Department of Mathematics, University of Richmond, Richmond, VA 23173, USA
| | - Casey P. Glasser
- Department of Mathematics, Virginia Tech, Blacksburg, VA 24061-1026, USA
| | - Joy A. Watson
- Department of Mathematics and Economics, Virginia State University, Petersburg, VA 23806, USA
| | - Yongjin Lu
- Department of Mathematics and Economics, Virginia State University, Petersburg, VA 23806, USA
| | - Jan Rychtář
- Department of Mathematics and Applied Mathematics, Virginia Commonwealth University, Richmond, VA 23284-2014, USA
| | - Dewey Taylor
- Department of Mathematics and Applied Mathematics, Virginia Commonwealth University, Richmond, VA 23284-2014, USA
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Xenodiagnosis leads the way: elimination of visceral leishmaniasis from the Indian subcontinent is feasible and sustainable. THE LANCET MICROBE 2021; 2:e2-e3. [DOI: 10.1016/s2666-5247(20)30222-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/30/2020] [Indexed: 11/21/2022] Open
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Sunyoto T, Boelaert M, Meheus F. Understanding the economic impact of leishmaniasis on households in endemic countries: a systematic review. Expert Rev Anti Infect Ther 2019; 17:57-69. [PMID: 30513027 DOI: 10.1080/14787210.2019.1555471] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 11/30/2018] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Leishmaniasis is a poverty-related disease that causes a significant socioeconomic burden to affected households. Visceral leishmaniasis is fatal if untreated, yet illness costs may lead to delays in accessing care. Skin manifestations of leishmaniasis cause a psychological burden and even longer treatment trajectories. The objective of this review is to evaluate illness costs associated with leishmaniasis across different settings (Asia, Africa, and Latin America) and the consequences to households. Areas covered: Through a systematic review of cost-of-illness studies, we documented the distribution of costs, the health-seeking behavior, and the consequences of leishmaniasis. We discuss the value of cost-of-illness studies for leishmaniasis. Expert commentary: Despite the free provision of diagnostics and treatment in the public health care sector, out-of-pocket payments remain substantial. There has been progress in addressing the economic burden of leishmaniasis, particularly through the elimination initiative in the Indian subcontinent. Though the illness cost is decreasing due to shorter treatment regimens and better access to care, the situation remains challenging in Africa. Improvement of control tools is critical. There is a need to update cost estimates to inform policy-making and ensure sustainable solutions to reduce financial barriers to leishmaniasis care, especially in pursuing universal health coverage.
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Affiliation(s)
- Temmy Sunyoto
- a Public Health Department , Institute of Tropical Medicine , Antwerpen , Belgium
| | - Marleen Boelaert
- a Public Health Department , Institute of Tropical Medicine , Antwerpen , Belgium
| | - Filip Meheus
- b Early Detection and Prevention Section , International Agency for Research on Cancer , Lyon , France
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Zijlstra EE, Alves F, Rijal S, Arana B, Alvar J. Post-kala-azar dermal leishmaniasis in the Indian subcontinent: A threat to the South-East Asia Region Kala-azar Elimination Programme. PLoS Negl Trop Dis 2017; 11:e0005877. [PMID: 29145397 PMCID: PMC5689828 DOI: 10.1371/journal.pntd.0005877] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background The South-East Asia Region Kala-azar Elimination Programme (KAEP) is expected to enter the consolidation phase in 2017, which focuses on case detection, vector control, and identifying potential sources of infection. Post-kala-azar dermal leishmaniasis (PKDL) is thought to play a role in the recurrence of visceral leishmaniasis (VL)/kala-azar outbreaks, and control of PKDL is among the priorities of the KAEP. Methodology and principal finding We reviewed the literature with regard to PKDL in Asia and interpreted the findings in relation to current intervention methods in the KAEP in order to make recommendations. There is a considerable knowledge gap regarding the pathophysiology of VL and PKDL, especially the underlying immune responses. Risk factors (of which previous VL treatments may be most important) are poorly understood and need to be better defined. The role of PKDL patients in transmission is largely unknown, and there is insufficient information about the importance of duration, distribution and severity of the rash, time of onset, and self-healing. Current intervention methods focus on active case detection and treatment of all PKDL cases with miltefosine while there is increasing drug resistance. The prevention of PKDL by improved VL treatment currently receives insufficient attention. Conclusion and significance PKDL is a heterogeneous and dynamic condition, and patients differ with regard to time of onset after VL, chronicity, and distribution and appearance of the rash, as well as immune responses (including tendency to self-heal), all of which may vary over time. It is essential to fully describe the pathophysiology in order to make informed decisions on the most cost-effective approach. Emphasis should be on early detection of those who contribute to transmission and those who are in need of treatment, for whom short-course, effective, and safe drug regimens should be available. The prevention of PKDL should be emphasised by innovative and improved treatment for VL, which may include immunomodulation.
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Affiliation(s)
- Eduard E. Zijlstra
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
- Rotterdam Centre for Tropical Medicine, Rotterdam, the Netherlands
- * E-mail:
| | - Fabiana Alves
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
| | - Suman Rijal
- Drugs for Neglected Diseases initiative, India Office, New Delhi, India
| | - Byron Arana
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
| | - Jorge Alvar
- Drugs for Neglected Diseases initiative, Geneva, Switzerland
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Rock KS, Quinnell RJ, Medley GF, Courtenay O. Progress in the Mathematical Modelling of Visceral Leishmaniasis. ADVANCES IN PARASITOLOGY 2016; 94:49-131. [PMID: 27756459 DOI: 10.1016/bs.apar.2016.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The leishmaniases comprise a complex of diseases characterized by clinical outcomes that range from self-limiting to chronic, and disfiguring and stigmatizing to life threatening. Diagnostic methods, treatments, and vector and reservoir control options exist, but deciding the most effective interventions requires a quantitative understanding of the population level infection and disease dynamics. The effectiveness of any set of interventions has to be determined within the context of operational conditions, including economic and political commitment. Mathematical models are the best available tools for studying quantitative systems crossing disciplinary spheres (biology, medicine, economics) within environmental and societal constraints. In 2005, the World Health Assembly and government health ministers of India, Nepal, and Bangladesh signed a Memorandum of Understanding to eliminate the life threatening form of leishmaniasis, visceral leishmaniasis (VL), on the Indian subcontinent by 2015 through a combination of early case detection, improved treatments, and vector control. The elimination target is <1 case/10,000 population at the district or subdistrict level compared to the current 20/10,000 in the regions of highest transmission. Towards this goal, this chapter focuses on mathematical models of VL, and the biology driving those models, to enable realistic predictions of the best combination of interventions. Several key issues will be discussed which have affected previous modelling of VL and the direction future modelling may take. Current understanding of the natural history of disease, immunity (and loss of immunity), and stages of infection and their durations are considered particularly for humans, and also for dogs. Asymptomatic and clinical infection are discussed in the context of their relative roles in Leishmania transmission, as well as key components of the parasite-sandfly-vector interaction and intervention strategies including diagnosis, treatment and vector control. Gaps in current biological knowledge and potential avenues to improve model structures and mathematical predictions are identified. Underpinning the marriage between biology and mathematical modelling, the content of this chapter represents the first step towards developing the next generation of models for VL.
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Affiliation(s)
- K S Rock
- University of Warwick, Coventry, United Kingdom
| | | | - G F Medley
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - O Courtenay
- University of Warwick, Coventry, United Kingdom
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Chapman LAC, Dyson L, Courtenay O, Chowdhury R, Bern C, Medley GF, Hollingsworth TD. Quantification of the natural history of visceral leishmaniasis and consequences for control. Parasit Vectors 2015; 8:521. [PMID: 26490668 PMCID: PMC4618734 DOI: 10.1186/s13071-015-1136-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/03/2015] [Indexed: 01/20/2023] Open
Abstract
Background Visceral leishmaniasis has been targeted for elimination as a public health problem (less than 1 case per 10,000 people per year) in the Indian sub-continent by 2017. However, there is still a high degree of uncertainty about the natural history of the disease, in particular about the duration of asymptomatic infection and the proportion of asymptomatically infected individuals that develop clinical visceral leishmaniasis. Quantifying these aspects of the disease is key for guiding efforts to eliminate visceral leishmaniasis and maintaining elimination once it is reached. Methods Data from a detailed epidemiological study in Bangladesh in 2002–2004 was analysed to estimate key epidemiological parameters. The role of diagnostics in determining the probability and rate of progression to clinical disease was estimated by fitting Cox proportional hazards models. A multi-state Markov model of the natural history of visceral leishmaniasis was fitted to the data to estimate the asymptomatic infection period and the proportion of asymptomatic individuals going on to develop clinical symptoms. Results At the time of the study, individuals were taking several months to be diagnosed with visceral leishmaniasis, leading to many opportunities for ongoing transmission. The probability of progression to clinical disease was strongly associated with initial seropositivity and even more strongly with seroconversion, with most clinical symptoms developing within a year. The estimated average durations of asymptomatic infection and symptomatic infection for our model of the natural history are 147 days (95 % CI 130–166) and 140 days (95 % CI 123–160), respectively, and are significantly longer than previously reported estimates. We estimate from the data that 14.7 % (95 % CI 12.6-20.0 %) of asymptomatic individuals develop clinical symptoms—a greater proportion than previously estimated. Conclusions Extended periods of asymptomatic infection could be important for visceral leishmaniasis transmission, but this depends critically on the relative infectivity of asymptomatic and symptomatic individuals to sandflies. These estimates could be informed by similar analysis of other datasets. Our results highlight the importance of reducing times from onset of symptoms to diagnosis and treatment to reduce opportunities for transmission. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1136-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lloyd A C Chapman
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK.
| | - Louise Dyson
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK
| | - Orin Courtenay
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK
| | - Rajib Chowdhury
- Country Programme Manager - Bangladesh, KalaCORE Programme, Dhaka, Bangladesh.,Department of Medical Entomology, National Institute of Preventive and Social Medicine (NIPSOM), Mohakhali, Dhaka, Bangladesh
| | - Caryn Bern
- UCSF School of Medicine, 550 16th Street, San Francisco, CA, 94158, USA
| | - Graham F Medley
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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Rahmatullah M, Khatun Z, Barua D, Alam MU, Jahan S, Jahan R. Medicinal plants used by traditional practitioners of the Kole and Rai tribes of Bangladesh. J Altern Complement Med 2013; 19:483-91. [PMID: 23343335 DOI: 10.1089/acm.2012.0227] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Mohammed Rahmatullah
- Faculty of Life Sciences, University of Development Alternative, Dhanmondi, Bangladesh.
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Bhunia GS, Kesari S, Chatterjee N, Kumar V, Das P. Telehealth: a perspective approach for visceral leishmaniasis (kala-azar) control in India. Pathog Glob Health 2012; 106:150-8. [PMID: 23265372 PMCID: PMC4001574 DOI: 10.1179/2047773212y.0000000014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Visceral leishmaniasis, also known as kala-azar, is a vector borne disease caused by the protozoan parasite, L. donovani. Poor and neglected populations in Indian sub-continent are particularly affected by this disease. Due to the diversity of epidemiological situations, no single diagnosis, treatment, or control will be suitable for all. Control measures through case findings, treatment, and vector control are seldom used, even where they could be useful. Modern tools like telehealth, using space technology, have now come in handy to address issues of disease surveillance, control checking, and evaluation. The present study focuses on telehealth as a current vector control strategy, perspectives on diagnosis, treatment, and control of visceral leishmaniasis as these deserve more attention and research.
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Affiliation(s)
- Gouri Sankar Bhunia
- Department of Vector Biology and Control, Rajendra Memorial Research Institute of Medical Sciences (ICMR), Patna, Bihar, India
| | - Shreekant Kesari
- Department of Vector Biology and Control, Rajendra Memorial Research Institute of Medical Sciences (ICMR), Patna, Bihar, India
| | - Nandini Chatterjee
- Department of Geography, Presidency University, Kolkata, West Bengal, India
| | - Vijay Kumar
- Department of Vector Biology and Control, Rajendra Memorial Research Institute of Medical Sciences (ICMR), Patna, Bihar, India
| | - Pradeep Das
- Department of Vector Biology and Control, Rajendra Memorial Research Institute of Medical Sciences (ICMR), Patna, Bihar, India
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