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

Transmission of vector-borne pathogens is often attributed to the environmental and biological drivers that determine ecological hazard. But whether hazard translates into realized infection risk is dependent on human behavior – how humans become exposed to sources of infection. In the Gran Chaco, where Chagas disease is endemic, we examined how kinship-based social networks shape transmission of Trypanosoma cruzi, the causative agent of Chagas disease. By reconstructing the kinship network of 403 households across Chaco Province, Argentina, we incorporated network measures into Bayesian spatial models of domiciliary vector infestation and child T. cruzi infection. Residential mobility (i.e., the relocation and rebuilding of houses) reduced both infestation and infection risk, but only among socially isolated households with no kinship ties; socially connectivity attenuated this protective effect. Network position also had a differential impact on child infection risk depending on local vector ecology. In domiciles where infected vectors were absent, living in a household with greater social accessibility amplified infection risk, but where infected vectors were present, greater social accessibility buffered against infection. These findings highlight how social organization intersects with ecological hazard to shape vector exposure and T. cruzi infection, highlighting the need to integrate behavioral connectivity into control strategies for vector-borne diseases.