Integrating age-dependent pig susceptibility and spatial exposure heterogeneity improves agent-based modeling of Taenia solium transmission.

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Citation abstract

Taenia solium causes an estimated 2.8 million disability-adjusted life years annually and substantial economic burdens in endemic regions. Understanding pig infection dynamics is essential for control, yet age-dependent susceptibility, acquired immunity, and spatially heterogeneous exposure are rarely represented in transmission models. We integrated experimental infection data across pig age groups into a local-scale agent-based model (ABM) of T. solium transmission. The model includes age-related susceptibility peaking at weaning, immunity elicited by egg exposure, and heterogeneous pig-environment interactions derived from GPS-tracked movements. We compared four model configurations: baseline, immunity only, exposure heterogeneity only, and combined. Calibration and validation used human taeniasis and pig cysticercosis prevalence data from eight rural Peruvian villages; intervention scenarios included mass vaccination and anthelmintic treatment. All configurations fit observed data well, but models incorporating heterogeneous susceptibility concentrated 95% of infections before 6.5 months (versus distributed across lifespan in baseline). The combined model best reproduced empirical cyst burden distributions, with 2.2% of pigs harboring 87% of total cysts, approaching the observed 99.2% aggregation. Immunity attenuated post-intervention prevalence rebounds. Mass pig vaccination reduced pig cysticercosis prevalence by 16% in models without immunity but had negligible effect when immunity was included, indicating age-targeted interventions are essential; lower age cut-off needs maternal immunity data for cost-effective control. Integrating pig immunity and exposure heterogeneity improves T. solium transmission model realism and provides a more accurate framework for intervention design and evaluation.