Visceral leishmaniasis elimination in India: progress and the road ahead

ABSTRACT

Introduction

As of 2021, visceral leishmaniasis (VL) elimination program has met with success in reducing the rate of VL to target levels in many locales, but there is persistence of low-level disease and sporadic outbreaks, sometimes in new locations. Thus, there is an urgent need to identify knowledge gaps and factors that impede total VL elimination.

Area covered

We reviewed the progress and current status of VL elimination program. We discuss the knowledge gaps influencing the success of elimination program and strategies to be required to ensure VL elimination as a public health problem is achieved and sustained.

Expert opinion

VL elimination is considered technically possible and operationally feasible owing to focal nature of transmission, absence of an animal reservoir, single vector, availability of an effective diagnostic test, use of a single dose of liposomal amphotericin B along with a strong political commitment. Substantial progress has been made in the reduction of VL incidence rates in the country. However, there are many challenges remain that need to be addressed if the elimination goal is to be reached and sustained. These are increasing relapse, outbreaks in new foci and increasing number of PKDL and HIV-VL co-infections.

KEYWORDS:

• Visceral leishmaniasis
• elimination
• endemic blocks
• drug treatment

Article highlights

• Elimination of VL from India is considered technically and operationally feasible as it is highly spatially and temporarily clustered suggests that disease transmission is focal.

• Strong political commitment exists.

• VL is notifiable disease in India.

• Cross border collaboration in the region has been initiated with the support of partners.

• Active case detection (ACD) of patients in endemic areas have enhanced early detection & treatment of PKDL as well as HIV/VL Co-infection.

• Only eight PHC blocks have >1 cases per 10, 000 population.

• Proportion of kala-azar amongst suspect kala-azar cases are decreasing.

• Diagnosis and treatment of PKDL and HIV-VL co-infection remains a major lacuna.

• Single dose AmBisome was rolled out in the VL elimination program in the year 2014. AmBisome is still a very effective drug and enables point of care treatment at the PHC level.

• Vector control through IRS is important and should be continued efficiently to sustain VL elimination.

• Outbreaks in new areas is a matter of great concern and can be prevented by maintaining clinical vigilance and by prompt diagnosis.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or material discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or mending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

The study was funded by theExtramural Program of the National Institute of Allergy and InfectiousDiseases, National Institutes of Health (TMRC grant number U19AI074321); Science & Engineering Research Board (SERB) [Grant No. SRG/2020/002558]; UGC-BSR Research start-up Grant; Institute of Eminence (IoE) grant of BanarasHindu University; and Bill& Melinda Gates Foundation (BMGF), USA (Grant No. number OPP1183986). Thefunders had no role in design, decision to publish, or preparation of thereport.