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Publications

Journal Article Ahead of print

PubMed: 42113878 DOI: 10.1371/journal.pntd.0013504

Mapping the last mile: Micro-stratification for sustained visceral leishmaniasis elimination in Bangladesh.

PLoS Negl Trop Dis 20(5):e0013504

Authors: Shomik Maruf, Rasel Uddin, Farhana Rahman Luba, Soumik Kha Sagar, Debashis Ghosh, Sakhawat Hossain, Megha Raj Banjara, Axel Kroeger, Christine Halleux, Abraham Aseffa, Dinesh Mondal

Affiliations

  • NTD Research Group, Nutrition Research Division, International Centre for Diarrhoeal Disease Research, Bangladesh (icddrb), Dhaka, Bangladesh.
  • National Kala-azar Elimination Programme (NKEP), Communicable Disease Control (CDC), Directorate General of Health Services (DGHS), Dhaka, Bangladesh.
  • Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal.
  • UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, Avenue Appia, Geneva, Switzerland.
  • Centre for Medicine and Society, Albert-Ludwigs-University, Freiburg, Germany.
  • Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia.

Abstract

BACKGROUND

Bangladesh became the first country to achieve World Health Organization (WHO) validation for eliminating visceral leishmaniasis (VL, Kala-azar) as a public-health problem in 2023. Sustaining this milestone demands a post-validation surveillance strategy that concentrates its efforts on residual transmission foci and deploys resources efficiently. We therefore conducted the country's first Mouza-level micro-stratification to refine risk maps and guide targeted interventions.

METHODS

The study used routinely reported VL line-list data (January 2017 - June 2025) from the national DHIS2 platform for every Upazila (sub-districts) that recorded ≥1 VL case. Each Mouza-the smallest administrative unit for land records comprising of one or more villages-was categorised as high (≥3 new VL cases), moderate (2 cases), low (1 case) or non-endemic (0 cases) over the nine-year period. Hot-spot maps were created in Python. Associations between endemicity (endemic vs non-endemic) were tested with chi-squared statistics, yielding odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Among 17,123 Mouzas in 128 case-reporting Upazilas, only 478 (2.8%) reported ≥1 new VL case between 2017 and 2025. High-endemic Mouzas (n = 33; 0.2%) accounted for 35% of total incident cases and clustered primarily in Mymensingh, Dhaka and Rajshahi divisions. However, year-on-year mapping showed reduction in the number of endemic Mouzas with no sustained new foci.

CONCLUSIONS

VL transmission in Bangladesh is now intensely focal, confined to <3% of Mouzas within historically endemic Upazilas. While broad surveillance coverage remains essential, micro-stratification at the Mouza level can guide the prioritization of targeted interventions, such as indoor residual spraying and active case detection in high-risk areas, improving program efficiency without compromising case detection. Periodic updating of Mouza-level risk maps will be essential to identify emerging hotspots, prevent resurgence, and inform strategies in other countries approaching VL elimination.

MeSH

Leishmaniasis, Leishmaniasis, Visceral