Nationwide seroprevalence and spatial distribution of Toxoplasma gondii in wild boar (Sus scrofa) in South Korea, 2022–2025

Toxoplasma gondii is a widespread zoonotic parasite that can infect nearly all warm-blooded vertebrates. Wild boars (Sus scrofa) are valuable indicator hosts because of their broad habitat use, omnivorous feeding behavior, and frequent contact with both natural and human-modified environments. However, comprehensive nationwide data on T. gondii exposure in wildlife in South Korea remain limited. This study aimed to investigate the seroprevalence, associated risk factors, and spatial distribution of T. gondii exposure in wild boars in South Korea using nationwide surveillance samples collected between 2022 and 2025. Seroprevalence remained consistently high, ranging from 61.7% in 2022 to 70.0% in 2025. Body weight was the strongest independent predictor of seropositivity, with higher body weights associated with greater odds of seropositivity. At the regional level, metropolitan areas generally had higher odds of seropositivity than non-metropolitan regions. Spatial analysis identified hotspots of high seroprevalence in central and southern South Korea. Local spatial autocorrelation analysis showed that high–high seroprevalence clusters were significantly associated with high densities of both cat and wild boar activity, with a stronger association for wild boar activity. This study provides nationwide baseline data on T. gondii seroprevalence in wild boars in South Korea and supports their use as sentinel hosts for wildlife toxoplasmosis surveillance within a One Health framework.