Fifty years of struggle to control cutaneous leishmaniasis in the highest endemic county in Iran: A longitudinal observation inferred with interrupted time series model

PLoS Negl Trop Dis. 2022 Apr 29;16(4):e0010271. doi: 10.1371/journal.pntd.0010271. eCollection 2022 Apr.

Abstract

Negligible data are available following major social activities and environmental changes on leishmaniasis. Therefore, how interactions between these events influence cutaneous leishmaniasis (CL) risk is not well-known. This longitudinal study was undertaken to explore the impact of interventions conducted between 1971 and 2020 in Bam county, which has had the highest disease burden in Iran. Only confirmed CL cases during this period were taken into account. Data were analyzed by SPSS 22 using the X2 test to assess the significance of the difference between proportions. Moreover, we used interrupted time series (ITS) to assess the impact of three environmental events during this period. Overall, 40,164 cases of CL occurred in the past five decades. Multiple complex factors were among the leading causes that synergistically induced the emergence/re-emergence of CL outbreaks in Bam. The main factors attributed negatively to CL control were cessation of malaria spraying activity, expansion of the city spaces, and a massive earthquake creating new breeding potentials for the vectors. The highest impact on CL incidence during these years was related to the earthquake [coefficient = 17.8 (95% CI: 11.3, 22.7); p-value < 0.001]. Many factors can contribute to CL outbreaks in endemic foci. They also can cause new foci in new areas. Since humans are the single reservoir for CL in this area, early detection and effective management significantly contribute to controlling CL to reduce the disease burden. However, essential evidence gaps remain, and new tools are crucial before the disease can ultimately be controlled. Nevertheless, sustained funding and more trained task forces are essential to strengthen surveillance and case management and monitor the interventions' impact.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Humans
  • Incidence
  • Interrupted Time Series Analysis
  • Iran / epidemiology
  • Leishmaniasis, Cutaneous* / epidemiology
  • Longitudinal Studies

Grants and funding

This project (no. 99001203) was supported by the Kerman University of Medical Sciences, Kerman, Iran (IS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.