AB121. Trends and climatic drivers of leptospirosis in Malaysia, 2012–2022: spatiotemporal analysis

Background: Leptospirosis remains a significant zoonotic disease in Malaysia, where climatic and environmental factors influence transmission dynamics. However, comprehensive national analyses of spatiotemporal patterns and their relationship to climate remain limited. The objective of the study is to describe the demographic characteristics, spatiotemporal patterns, and density; identify spatiotemporal clustering and hotspots; and determine the association between climatic conditions and state-level leptospirosis incidence in Malaysia from 2012 to 2022.

Methods: A retrospective ecological study was conducted using 51,564 leptospirosis cases reported across Malaysia from 2012 to 2022. Demographics and spatiotemporal patterns were presented accordingly, and density was assessed using kernel density estimates (KDE). Spatiotemporal clustering and hotspots were identified using the nearest neighbor index (NNI), spatial autocorrelation (Global Moran’s I), local indicators of spatial association (LISA), and Getis-Ord Gi* statistics. Associations between climatic factors and annual state-level incidence were determined using a generalized linear mixed model (GLMM).

Results: Most cases were in males (68.1%) and Malay Bumiputera (62.6%), with a median age of 30 years. Case numbers peaked in 2014–2016 and 2022, with higher density observed in parts of Peninsular Malaysia and Sarawak. Spatial clustering was seen every year (NNI 0.19–0.28; Moran’s I 0.02–0.21). LISA found persistent hotspots in rural areas of Sarawak, while others appeared intermittently. Getis-Ord Gi* confirmed the persistence and spread of these high-risk areas. Temperature was inversely associated with leptospirosis incidence [incidence rate ratio (IRR) =0.88; 95% confidence interval (CI): 0.78–0.99], while rainfall, humidity, and flooding were not statistically significant.

Conclusions: The local climate and environment strongly shape leptospirosis in Malaysia, with certain areas consistently experiencing higher risk. Focusing prevention efforts in these hotspots, while considering ongoing changes in climate and environment, can improve disease control. These strategies may also be useful for managing leptospirosis and similar diseases in other countries with changing environments.

Keywords: Climate; clustering; hotspots; leptospirosis; Malaysia