Impact of Intensified Control Strategies on Incidence of Visceral Leishmaniasis in a Highly Endemic District of Bihar, India

Abstract

Background: Visceral leishmaniasis (VL) is declining in India, but still persists in disadvantaged communities despite WHO's 2020 'elimination as a public health problem' target. Combined interventions might achieve elimination if we knew their impact. Furthermore WHO's forthcoming NTD road map has opened a policy window for strategy change for 2021-2030. We estimated the combined effect from a district-wide pilot of intensified interventions in the highly endemic Vaishali district, where cases fell from 3,598 in 2012-2014 to 708 in 2015-2017. Methods: The intensified control approach comprised indoor residual spraying with improved supervision; VL-specific training for Accredited Social Health Activists to reduce onset-to-diagnosis time; and increased Information Education and Communication activities in the community. We compared the rate of incidence decrease in Vaishali to other districts in Bihar via an interrupted time series analysis with a spatiotemporal model, and estimated the number of cases averted by the pilot. Findings: Changes in Vaishali's rank among Bihar's endemic districts in terms of monthly case numbers showed a change pre-pilot (3rd highest out of 33 reporting districts) versus during the pilot (9th) (p<0·0001). The rate of decline in Vaishali's cases was 26th highest pre-pilot and 19th during the pilot (p<0·0001). Model simulations suggest a median 1,071 cases (IQR 849-1,333) were averted in Vaishali between March 2015-December 2017. Interpretation: Strengthening control strategies may have precipitated a faster decline in VL case numbers in Vaishali and suggests this approach should be piloted in other highly endemic districts. Funding: Government of India, Bill & Melinda Gates Foundation, Newton Fund. Declaration of Interest: VK, NAS, SK, VNRD, KP& PD were the permanent employees of RMRIMS, Patnaand RM was a PhD337student under Department of Vector Biology, RMRIMS, Patna. Government of India entrusted RMRIMS with thispilotwork. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest Ethical Approval: The Institutional Ethical Committee of RMRIMS(03/RMRI/EC/2018)approved the intensified control programme.University of Warwick’s Biomedical & Scientific Research Ethics Committee (REGO-662018-2231) approved this analysis