Spillback in the Anthropocene: the risk of human-to-wildlife pathogen transmission for conservation and public health

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint.

Add a Comment

You must log in to post a comment.


There are no comments or no comments have been made public for this article.


Download Preprint

Supplementary Files

Anna C Fagre, Lily Cohen, Evan A. Eskew, Maxwell Jenner Farrell, Emma Glennon, Maxwell B Joseph , Hannah K. Frank, Sadie Jane Ryan, Colin J. Carlson, Gregory Albery


The SARS-CoV-2 pandemic has led to increased concern over transmission of pathogens from humans to animals (“spillback”) and its potential to threaten conservation and public health. To assess this threat, we reviewed published evidence of spillback events, including instances where spillback could threaten conservation and human health. We identified 97 verified examples of spillback, involving a wide range of pathogens; however, infected hosts were mostly non-human primates or large, long-lived captive animals. Relatively few spillback events resulted in morbidity and mortality, and very few led to maintenance of a human pathogen in a new reservoir or subsequent “secondary spillover” back into humans. Together, these results imply that spillback represents an apparently minor threat to conservation and public health, particularly relative to other anthropogenic stressors like land use and climate change. Lastly, we outline how researchers can collect experimental and observational evidence that will expand our capacity for spillback risk assessment.




Bacteriology, Biodiversity, Biology, Ecology and Evolutionary Biology, Immunology and Infectious Disease, Life Sciences, Medicine and Health Sciences, Microbiology, Public Health, Veterinary Infectious Diseases, Veterinary Medicine, Veterinary Microbiology and Immunobiology, Veterinary Preventive Medicine, Epidemiology, and Public Health, Virology


Anthropocene, COVID-19, cross-species transmission, multi-host pathogen, reverse zoonosis, SARS-CoV-2, spillback, zooanthroponosis


Published: 2021-04-11 20:25


CC-By Attribution-ShareAlike 4.0 International