Kala-azar elimination in a highly-endemic district of Bihar, India: A success story

Abstract

Background: Visceral leishmaniasis (VL) or Kala-azar has been a major public health problem in Bihar, India, for several decades. A few VL infected districts including Vaishali have reported >600 cases annually. Hence, in 2015, the Government of India entrusted ICMR-Rajendra Memorial Research Institute of Medical Sciences, Patna, to implement an integrated control strategy for achieving the VL elimination target (<1 case per 10,000 people at the block level) in the Vaishali District of Bihar.

Methodology: This study was conducted between January 2015 and December 2016. An integrated control strategy including the spatio-temporal mapping of VL-case distribution, active case detection, chemical-based vector control using indoor residual spraying (IRS), community awareness campaigns, the training of IRS members, the training of medical doctors for effective treatment, daily monitoring and the supervision of IRS activities, logistic management, post-IRS quality assurance, epidemiological surveillance, and entomological monitoring was performed. An insecticide quantification test was performed for evaluating the IRS quality on sprayed walls. A modern compression pump was used to maintain spray quality on different wall surfaces. The impact of IRS was assessed through sand fly collection in human dwellings and cattle sheds in pre- and post-IRS. The insecticide susceptibility of local P. argentipes was performed before each IRS round (in February and June) during 2015-2016. Statistical analysis such as the mean, percentage, and 95% CI were used to summarize the results.

Findings: All 16 blocks of the Vaishali District achieved the VL elimination target in 2016. The integrated VL control strategy helped reduce the number of VL cases from 664 in 2014 to 163 in 2016 and the number of endemic villages from 282 in 2014 to 142 in 2016. The case reduction rate was increased from 22.6% in 2014 to 58.8% in 2016. On average, 74 VL infected villages became Kala-azar free each year from 2015 to 2016.

Conclusions: The results of this study suggest that the elimination of VL is possible from all endemic blocks of Bihar if the integrated Vaishali VL control strategy is applied under strong monitoring and supervision.

Fig 1. Map of the study area showed the location of Bihar in India and the location of Vaishali in Bihar.

A GIS-database built in the remote sensing project of ICMR-Rajendra Memorial Research Institute of Medical Sciences was used to create the maps in the figure.

Fig 2. The three-tier monitoring and supervision system adopted by RMRIMS for IRS-based VL vector control program in the Vaishali District, Bihar, India.

Fig 3

IQK-based DDT quantification post-IRS HHs sprayed by HCP (Panel A) and CSP (Panel B) assessed for undersprayed, on target, and oversprayed in first round of IRS in 2015 in the Vaishali District, Bihar.

Fig 4. The number of VL cases and affected villages reported each year during 2012–2016 in the Vaishali District, Bihar.

The case reduction rate (CRR) was calculated between 2013 and 2016.

Fig 5. The case wise annual distribution of VL-affected villages during 2014–2016 in the Vaishali District, Bihar.