Public recreational areas as potential environments for Aedes breeding in Malaysia: an entomological survey

Abstract Dengue fever remains a major public health concern in Malaysia, driven by the widespread presence of Aedes aegypti and Aedes albopictus. While surveillance efforts have traditionally focused on residential environments, public recreational areas may serve as under-recognized habitats for vector breeding. A cross-sectional entomological survey was conducted from February to April 2025 across 34 public recreational sites in nine Malaysian states and two federal territories. Systematic larval inspections were performed on artificial and natural water-holding containers. The Container Index (CI%) was calculated and used to classify sites into low (< 3%), moderate (3–15%), and high (> 15%) risk categories. Sites were further characterized based on urbanicity (urban vs. suburban/peri-urban) and environmental context. Data were analysed using descriptive statistics and non-parametric inferential tests, including Spearman’s rank correlation to assess the relationship between container abundance and CI%, Kruskal–Wallis tests to compare CI% across states, and Mann–Whitney U tests to evaluate differences between urban and suburban/peri-urban sites. Container Index values ranged from 0.00% to 50.00%, with 6 sites (17.6%) classified as high risk, 19 (55.9%) as moderate risk, and 9 (26.5%) as low risk. High-risk sites were identified in both urban and suburban/peri-urban settings, indicating that elevated infestation is not restricted to densely populated areas. No statistically significant association was observed between the number of containers inspected and CI% (ρ = 0.149, p = 0.4003). Similarly, no significant differences were found across states (H = 7.854, p = 0.1645) or between urban and suburban/peri-urban sites (U = 147.500, p = 0.2992). Observational assessment identified recurrent breeding microhabitats, including artificial disposable containers, vegetative debris, and poorly maintained drainage systems; however, these were not quantitatively modelled against CI% values. Public recreational areas represent under-recognized environments for Aedes breeding, with infestation patterns driven more by localized ecological conditions than by container abundance or broad geographic classification. Integrating entomological indices with environmental assessment provides a practical framework for identifying site-specific vector risks. These findings support expanding vector surveillance and control strategies beyond residential settings to include public-use environments.