Human social networks modify eco-social drivers of Trypanosoma cruzi transmission in rural Argentina

In Argentina’s Gran Chaco region, human Trypanosoma cruzi infection is hyperendemic among rural communities. Intense residential moving in these areas has been shown to disrupt sustained exposure to vector infestation, underscoring the role of human movement in shaping vector-borne disease risk. However, the impact of individual-level movement, as motivated by social networks, on domiciliary infestation and human T. cruzi infection remains largely unexamined. Herein, we reconstructed the kinship network of 403 households across rural communities of Chaco Province, Argentina, using parent-child ties to capture intergenerational movement. Applying Bayesian spatial modeling, we examined how social connectivity, as a proxy for human movement, influenced house infestation and child infection, adjusting for spatial structure and eco-social factors. We found that social connectivity modified the protective effect of mobility. While moving alone was generally associated with lower odds of infestation, mobile households maintaining social ties experienced increased odds of both house infestation and child infection, suggesting that social relationships may sustain or reintroduce exposure risks even after a household has relocated. Additionally, the impact of infected vectors on infection was attenuated in households with higher harmonic centrality (i.e., greater network accessibility). Children in highly accessible households with low vector abundance faced similar infection odds as those in less accessible households with higher vector abundance, possibly due to exposures accumulated across multiple pathways, diminishing the relative influence of local entomological risk. In summary, our findings suggest that social networks may facilitate passive vector transport or sustained vector exposure through travel between connected households, a factor that should be integrated into vector control strategies in socially complex settings.