Humanity just made it through the challenges posed by the COVID-19 pandemic. In the past 20 years, our society has seen multiple notable human outbreaks of infectious diseases, including the avian influenza, zika virus and of course severe acute respiratory syndrome (SARS). Among those emerging diseases, about two-third have been reported to be of zoonotic origin with 75% of them are believed to have a wildlife origin. Modern agriculture is considered as and shown to be an accelerator for pathogens cross-over to human populations in various studies. Deforestation and landscape fragmentation reduce biodiversity while increase the likelihood of contact between infected wildlife and humans. Ecologists from University of Michigan (U-M) indeed hold an opposite view towards the prevailing idea of agriculture promoting zoonotic spread and spillover. Large-scale industrial monocultural plantations destroy the local biodiversity, narrowing the species-rich collection of animals into a few species harbouring pathogens, which catalyses the evolution of pathogens into new variants which are capable of infecting the humans. For example, oil palm monocultural plantations favours the gathering of bats, key reservoirs of Ebola, which may in turn enhance bat-human contact, thereby promoting pathogen spillover into human populations. In contrast, unlike industrial farms with regular traffic between city and countryside, small-scale and diversified farms rarely associate with close and frequent contact between pathogen reservoirs and agriculture workers. Reservoir-to-human and human-to-human transmissions are largely limited. To prevent future zoonotic spread and spillover, the U-M ecologist proposed an agricultural matrix framework that can be used to determine the relationship between agriculture and zoonotic diseases. It helps to distinguish different types of agriculture practices and examine if the dynamics of species abundance and diversity that favour the evolution of a pathogen capable of infecting human. The main focus of the framework is promoting agricultural practices that boost biodiversity and help creating pathogen barriers, while minimizing conditions that promotes pathogenic incubation. Ultimately, the team expect their work can lead to coherent, practical and effective actions which may raise adequate sociopolitical attention.

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Perfecto I, et al. One Earth. 2023 Sep 15;6(9):1131-1142