Spatial patterns of laboratory-confirmed leptospirosis in north-eastern Peninsular Malaysia, 2016-2023

Leptospirosis presents significant public health challenges in endemic regions such as north-eastern Peninsular Malaysia. Spatial analysis is essential for visualising disease incidence and distribution, assessing vulnerability based on geographical and socioeconomic factors, and ultimately informing targeted interventions, optimising resource allocation, and enhancing surveillance strategies. This study aimed to determine the incidence and characterise the spatial distribution of leptospirosis in Kelantan, Malaysia.

All laboratory-confirmed leptospirosis cases reported in Kelantan between 2016 and 2023 were extracted from the Communicable Disease Control Information System e-Notifikasi online database. Spatial analyses were performed using the spatstat, spdep, and ggplot2 packages within the RStudio integrated development environment.

The analysis encompassed 1,534 laboratory-confirmed leptospirosis cases. The average crude annual incidence of leptospirosis cases per 1,000 population from 2016 to 2023 was 0.101 (95% confidence interval, 0.038 to 0.164). Incidence varied considerably across districts and subdistricts, initially higher in the north but declining over time, while consistently high and increasing incidence was observed in the southern region. Significant clustering of leptospirosis cases occurred throughout the studied years, except during the coronavirus disease 2019 pandemic. Hotspots were initially prevalent in northern areas but later emerged in south-eastern and southern regions. Significant spatial autocorrelation evolved from high-low to high-high clusters, particularly evident in central and southern regions.

This study provides valuable local epidemiological and spatial insights into the endemicity of leptospirosis. The findings highlight the need for targeted interventions and continued surveillance to effectively mitigate the leptospirosis burden in endemic areas.