Global shifts in mammalian population trends reveal key predictors of virus spillover risk

Abstract

Cite this article: Johnson CK, Hitchens PL, Pandit PS, Rushmore J, Evans TS, Young CCW, Doyle MM. 2020 Global shifts in mammalian population trends reveal key predictors of virus spillover risk. Proc. R. Soc. B 287: 20192736. http://dx.Emerging infectious diseases in humans are frequently caused by pathogens originating from animal hosts, and zoonotic disease outbreaks present a major challenge to global health. To investigate drivers of virus spillover, we evaluated the number of viruses mammalian species have shared with humans. We discovered that the number of zoonotic viruses detected in mammalian species scales positively with global species abundance, suggesting that virus transmission risk has been highest from animal species that have increased in abundance and even expanded their range by adapting to human-dominated landscapes. Domesticated species, primates and bats were identified as having more zoonotic viruses than other species. Among threatened wildlife species, those with population reductions owing to exploitation and loss of habitat shared more viruses with humans. Exploitation of wildlife through hunting and trade facilitates close contact between wildlife and humans, and our findings provide further evidence that exploitation, as well as anthropogenic activities that have caused losses in wildlife habitat quality, have increased opportunities for animal-human interactions and facilitated zoonotic disease transmission. Our study provides new evidence for assessing spillover risk from mammalian species and highlights convergent processes whereby the causes of wildlife population declines have facilitated the transmission of animal viruses to humans.

Levers and leverage points for pathways to sustainability

“…Improved traceability and transparency in supply chains and requirements for corporate due diligence are important steps [lever E] but would need enhanced transparency of environmental impacts and new measures for intervention in order to facilitate internalizing the many spillover effects of trade.

While acknowledgement of the importance of externalities and telecouplings is central to whole fields such as environmental and ecological economics, the systemic elucidation and internalization called for here go well beyond what is generally cited as necessary action (Secretariat of the Convention on Biological Diversity, 2014; UN Environment, 2019a, 2019b). This leverage point has taken on newfound importance with the COVID‐19 pandemic, which highlights that consumers’ demand for some products results in harm to distant ecosystems, thus raising the risk of zoonotic emerging infectious diseases that can have global impacts (Johnson et al., 2020; Jones et al., 2008).

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COVID-19 and the Curse of Piecemeal Perspectives

“…Any efforts to make our world safer are doomed to fail unless they address the critical interface between people and pathogens, and the existential threat of climate change, that is making our Earth less habitable” ( 18 ). We also have to acknowledge that zoonotic spillover events and subsequent outbreaks are inevitable, as the interfaces between wildlife and humans increase, primarily due to deforestation and agricultural expansion ( 19 ). However, our collective and determined actions can prevent outbreaks from becoming global pandemics.…”

“…Numerically abundant orders such as rodents and bats harbor more viruses, but the notion of “special viral reservoirs” has recently been revoked ( 24 ). Most pathogens in wildlife remain unidentified, and many spillover events are overlooked ( 19 ). Less than 300 viruses from 25 high-risk viral families in mammals and birds are known to infect people.…”

SARS-CoV-2 emergence and diffusion: a new disease manifesting human–environment interactions and a global geography of health

“…Extensive research now demonstrates that many geographic contexts offer opportunities for viruses to spill over, also for coronaviruses (e.g. modes of livestock rearing, forest encroachment, urban growth), also for coronaviruses [ 12 , 13 ]. Bats, as a large reservoir, may play a prominent role [ 14 ], but that should not mean that we could focus on single human infrastructures or landscapes as such.…”