Elimination of visceral leishmaniasis on the Indian subcontinent (original) (raw)
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PLOS Neglected Tropical Diseases
Background The decade following the Regional Strategic Framework for Visceral Leishmaniasis (VL) elimination in 2005 has shown compelling progress in the reduction of VL burden in the Indian subcontinent. The Special Programme for Research and Training in Tropical Diseases (TDR), hosted by the World Health Organization (WHO) and other stakeholders, has coordinated and financed research for the development of new innovative tools and strategies to support the regional VL elimination initiative. This paper describes the process of the TDR's engagement and contribution to this initiative. Methodology/principal findings Multiple databases were searched to identify 152 scientific papers and reports with WHO funding or authorship affiliation around the following 3 framework strategies: detection of new cases, morbidity reduction, and prevention of infection. TDR has played a critical role in the evaluation and subsequent use of the 39-aminoacid-recombinant kinesin antigen (rK39) rapid diagnostic test (RDT) as a confirmatory test for VL in the national program. TDR has supported the clinical research and development of miltefosine and single-dose liposomal amphotericin B as a first-line treatment against VL. TDR has engaged with incountry researchers, national programme managers, and partners to generate evidencebased interventions for early detection and treatment of VL patients. TDR evaluated the quality, community acceptance, and cost effectiveness of indoor residual spraying, insecticide-treated bed nets, insecticide-impregnated durable wall linings, insecticidal paint, and
Visceral leishmaniasis elimination targets in India, strategies for preventing resurgence
Expert Review of Anti-infective Therapy, 2018
Introduction: Visceral leishmaniasis (VL) is a fatal parasitic disease caused by parasite belonging to Leishmania donovani complex and transmitted by infected female Phlebotomous argentipes sand flies. VL elimination strategy in the Indian subcontinent, that has a current goal of reducing the incidence of VL to below 1/10,000 of population by the year 2020, consists of rapid detection and treatment of VL to reduce the number of human reservoirs, and vector control using indoor residual spraying (IRS). However, as the incidence of VL declines towards the elimination goal, greater targeting of control methods will be required to ensure appropriate early action to prevent the resurgence of VL. Area Covered: We discuss the current progress and challenges in VL elimination program, and strategies to be employed to ensure sustained elimination of VL. Expert opinion: VL elimination initiative has saved many human lives; however, for VL elimination to become a reality in a sustained way, an intense effort is needed, as substantial numbers of endemic sub-districts (PHC blocks level) are yet to reach the elimination target. In addition to effective epidemiological surveillance, appropriate diagnostic and treatment services for VL at primary health centers will be needed to ensure long term sustainability and prevent reemergence of VL.
Innovations for the elimination and control of visceral leishmaniasis
PLOS Neglected Tropical Diseases, 2019
Visceral leishmaniasis (VL), a disease associated with poverty, is endemic in the Indian subcontinent and Africa (where it is caused by the protozoan parasite Leishmania donovani, and in Latin America and the Mediterranean region (where it is caused by L. infantum). In all regions, it is transmitted by the female sand fly vector. Although there has been a substantial decline in the number of reported cases in recent years, VL continues to affect many tropical and subtropical countries, despite international, national, and local efforts towards its control and elimination over the past several decades. In 2005, a target for the elimination of VL, defined as reducing incidence to a level where it would no longer be of public health importance, i.e., <1 per 10,000 inhabitants per year at each health intervention unit from India, Nepal, and Bangladesh, was set for 2015. This target date was missed, as was a second target date of 2017. WHO has recently reset the target date to 2020 for the elimination of this disease from the Indian subcontinent (ISC). To review the progress and prospects made towards elimination, an International Conference on Innovations for the Elimination and Control of Visceral Leishmaniasis (IEC-VL'18) was held in New Delhi, India from 28-30 November 2018. Discussions and debates throughout the conference were aimed to provide a focus for stakeholders and decision makers to frame further control measures and policies and to define needed research and tools. Thus, innovations that would be key during the "last mile" towards reaching the elimination targets needed emphasis. A focus on the challenges due to loss of immunity, parasite and human population heterogeneities, noncompliance to control measures, and reasons for outbreaks and resurgence of the disease is needed. Significant advances in the discovery and development of new drugs, diagnostics, vaccines, and vector control measures that offer opportunities for future interventions need to be highlighted.
PLoS Neglected Tropical Diseases, 2021
Background In 2005, Bangladesh, India and Nepal agreed to eliminate visceral leishmaniasis (VL) as a public health problem. The approach to this was through improved case detection and treatment, and controlling transmission by the sand fly vector Phlebotomus argentipes, with indoor residual spraying (IRS) of insecticide. Initially, India applied DDT with stirrup pumps for IRS, however, this did not reduce transmission. After 2015 onwards, the pyrethroid alpha-cypermethrin was applied with compression pumps, and entomological surveillance was initiated in 2016. Methods Eight sentinel sites were established in the Indian states of Bihar, Jharkhand and West Bengal. IRS coverage was monitored by household survey, quality of insecticide application was measured by HPLC, presence and abundance of the VL vector was monitored by CDC light traps, insecticide resistance was measured with WHO diagnostic assays and case incidence was determined from the VL case register KAMIS. Results Complete...
Parasitology, 2018
SUMMARYLeishmania donovani, the most virulent species of Leishmania, is found in the South Asian region that harbours the majority of visceral leishmaniasis (VL) cases in the world. The traditionally accepted relationships between the causative species of Leishmania and the resultant disease phenotype have been challenged during recent years and have underscored the importance of revisiting the previously established taxonomy with revisions to its classification. The weak voice of the afflicted with decades of neglect by scientists and policy makers have led to the miserably inadequate and slow advancements in product development in the fields of diagnostics, chemotherapeutics and vector control that continue to hinder the effective management and control of this infection. Limitations notwithstanding, the regional drive for the elimination of VL initiated over a decade ago that focused on India, Nepal and Bangladesh, the three main afflicted countries in the Indian subcontinent is ...
Asymptomatic Leishmania infections in northern India: a threat for the elimination programme?
Transactions of the Royal Society of Tropical Medicine and Hygiene, 2014
Visceral leishmaniasis (VL) continues to embody as a mammoth public health problem and hurdle to the socioeconomic development of Bihar, India. Interestingly, all leishmanial infections do not lead to overt clinical disease and may stay asymptomatic for a period of time. Asymptomatic cases of VL are considered as probable potential reservoirs of VL, and thus can play a major role in transmission of the disease in highly endemic areas of Bihar, India. They outnumber the exact disease burden in endemic areas of this region, thus jeopardizing the goal of the elimination program that is due by 2015. This article discusses the potential risk factors, epidemiological markers of transmission and requirement of highly sensitive diagnostic tools for efficient recognition of the high risk groups of conversion to symptomatic for proper designing of strategies for implementation of the control programs.
Lancet Infectious Diseases, 2002
Visceral leishmaniasis is common in less developed countries, with an estimated 500 000 new cases each year. Because of the diversity of epidemiological situations, no single diagnosis, treatment, or control will be suitable for all. Control measures through case finding, treatment, and vector control are seldom used, even where they could be useful. There is a place for a vaccine, and new imaginative approaches are needed. HIV coinfection is changing the epidemiology and presents problems for diagnosis and case management. Field diagnosis is difficult; simpler, less invasive tests are needed. Current treatments require long courses and parenteral administration, and most are expensive. Resistance is making the mainstay of treatment, agents based on pentavalent antimony, useless in northeastern India, where disease incidence is highest. Second-line drugs (pentamidine and amphotericin B) are limited by toxicity and availability, and newer formulations of amphotericin B are not affordable. The first effective oral drug, miltefosine, has been licensed in India, but the development of other drugs in clinical phases (paromomycin and sitamaquine) is slow. No novel compound is in the pipeline. Drug combinations must be developed to prevent drug resistance. Despite these urgent needs, research and development has been neglected, because a disease that mainly affects the poor ranks as a low priority in the private sector, and the public sector currently struggles to undertake the development of drugs and diagnostics in the absence of adequate funds and infrastructure. This article reviews the current situation and perspectives for diagnosis, treatment, and control of visceral leishmaniasis, and lists some priorities for research and development.
PLOS Neglected Tropical Diseases, 2016
Background As Bangladesh, India and Nepal progress towards visceral leishmaniasis (VL) elimination, it is important to understand the role of asymptomatic Leishmania infection (ALI), VL treatment relapse and post kala-azar dermal leishmaniasis (PKDL) in transmission. Methodology/ Principal Finding We reviewed evidence systematically on ALI, relapse and PKDL. We searched multiple databases to include studies on burden, risk factors, biomarkers, natural history, and infectiveness of ALI, PKDL and relapse. After screening 292 papers, 98 were included covering the years 1942 through 2016. ALI, PKDL and relapse studies lacked a reference standard and appropriate biomarker. The prevalence of ALI was 4-17-fold that of VL. The risk of ALI was higher in VL case contacts. Most infections remained asymptomatic or resolved spontaneously. The proportion of ALI that progressed to VL disease within a year was 1.5-23%, and was higher amongst those with high antibody titres. The natural history of PKDL showed variability; 3.8-28.6% had no past history of VL treatment. The infectiveness of PKDL was 32-53%. The risk of VL relapse was higher with HIV co-infection. Modelling studies predicted a range of scenarios. One model predicted VL elimination was unlikely in the long term with early diagnosis. Another model estimated that ALI contributed to 82% of the overall transmission, VL to 10% and PKDL to 8%. Another model predicted that VL cases were the main driver for transmission. Different models predicted VL elimination if the sandfly density was reduced by 67% by killing the sandfly or by 79% by reducing their breeding sites, or with 4-6y of optimal IRS or 10y of sub-optimal IRS and only in low endemic setting.