Vegetation cover and biodiversity reduce parasite infection in wild hosts across ecological levels and scales

Land use changes and biodiversity loss critically disrupt ecosystem
functioning and are major drivers of infectious disease outbreaks.
Trypanosoma cruzi, the agent of Chagas disease, is a multi-host parasite
whose epidemiology has changed due to the expansion of anthropogenic
activities over natural areas. We aimed to understand the ecological
processes increasing parasite prevalence at the individual, the community
and the landscape levels using the largest database on small mammal
infection by T. cruzi in Brazil. We applied machine learning techniques
and structural equation models to show that allometric traits and the
relative abundance of rodents in the community were important predictors
of infection risk, followed by variables associated with the landscape
environmental quality. Natural vegetation cover change and the taxonomic
and functional dimensions of biodiversity indirectly reduced infection
through its effect on the abundance distribution and composition of host
communities. According to our findings, approaches to biodiversity
conservation and restoration based on the integration of social inclusion
and human welfare would contribute to regulating the prevalence of T.
cruzi in wild hosts, which may reduce overall transmission risk.