Integrated active surveillance for post-kala-azar dermal leishmaniasis and leprosy in Bihar, India: a cross-sectional study (2016–2019)
Kuldeep Singh Deepak, Monal Trisal, Jyoti Mishra, Ashish SinhaAbstract
Background:
Post-kala-azar dermal leishmaniasis (PKDL) and leprosy are neglected tropical diseases (NTDs) prevalent in Bihar, India. Both present with overlapping skin lesions, often leading to misdiagnosis, delayed treatment, and social stigma. Misclassification prolongs disease transmission cycles and increases community mistrust. Deep-rooted social stigma surrounding leprosy further compounds the problem by deterring patients from seeking timely care, resulting in a hidden disease burden within communities.
Materials and Methods:
Between 2016 and 2019, active case detection (ACD) campaigns in 960 villages across 18 districts of Bihar screened approximately 2.49 million individuals. Suspected cases of PKDL and leprosy were evaluated through clinical examination, rK39 testing, and sensory assessment of skin lesions. Field teams, including Accredited Social Health Activists and trained field mobilizers, were equipped to differentiate between the two diseases. Government-supported patient incentives, including compensation for loss of wages and free transport to diagnostic camps, were provided to reduce barriers to participation. Private practitioners were also engaged as sentinel reporters and trained to notify the program when they identified suspected cases.
Findings:
Of the 1718 suspected PKDL cases, 690 were confirmed as PKDL, 26 as leprosy, and 3 previously diagnosed as leprosy were reclassified as PKDL. To ensure diagnostic quality, comprehensive case documentation of 9–10 pages per patient for 17 leprosy-positive cases was compiled and sent to a regional medical college for independent expert reconfirmation; all 17 were confirmed positive. Of the 26 confirmed leprosy cases, 17 underwent formal external validation. The remaining nine cases were not submitted for external validation due to logistical constraints, including incomplete documentation at the time of review and patient unavailability for follow-up. This partial validation limits the generalizability of the diagnostic accuracy statement; the 17 validated cases should be interpreted as a quality assurance subsample rather than a formal accuracy measure for all 26 cases. Many patients concealed skin lesions due to stigma but were reached through house-to-house ACD.
Interpretation:
Integrated surveillance for leprosy and PKDL within ACD programs can reduce diagnostic errors, improve patient outcomes, and reduce social stigma. Government incentives and private-sector engagement are essential enablers of early case detection.
Conclusion:
Cross-program data sharing, frontline health worker training, engagement of private practitioners, and community education will strengthen India’s NTD elimination strategies.