Social organization patterns can lower disease risk without associated disease avoidance or immunity

Increasing levels of social contact are often linked with increased risks of horizontal disease transmission. However, it is not immediately apparent whether particular social organization strategies could act as effective endogenous mechanisms to offset these increased risks. Patterns of a contact network structure could therefore convey dual evolutionary benefits, providing individuals with well-organized social systems and simultaneous reduction in pathogen pressure. This could then lead to runaway processes, increasing the complexity of a social interaction pattern without the parallel evolution of mechanisms that mitigate epidemiological risks, such as physiological immunity or avoidance of carriers. Using dynamic network models capable of independently simulating social choice and pathogen transmission, we demonstrate that emergent social organization could protect populations from the spread of pathogens. We further show that, while these effects are system-independent, they rely on both the social organization of host populations and the etiological properties of the pathogen. We demonstrate that, under certain scenarios, increased complexity of social network structure could have evolved in response to pathogen pressure rather than in spite of it.

► We model independent social and disease processes in dynamic social networks.
► We correlate social organization with disease burden across different systems.
► Increased social complexity can lower disease risks without immunity or avoidance.
► Social complexity can evolve to reduce pathogen pressure and not in spite of it.
► Organizational effects on disease propagation depend on pathogen characteristics.