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Urban-adapted mammal species have more known pathogens


The world is rapidly urbanizing, inviting mounting concern that urban environments will experience increased zoonotic disease risk. Urban animals could have more frequent contact with humans, therefore transmitting more zoonotic parasites; however, this relationship is complicated by sampling bias and phenotypic confounders. Here we test whether urban mammal species host more zoonotic parasites, investigating the underlying drivers alongside a suite of phenotypic, taxonomic and geographic predictors. We found that urban-adapted mammals have more documented parasites and more zoonotic parasites: despite comprising only 6% of investigated species, urban mammals provided 39% of known host–parasite combinations. However, contrary to predictions, much of the observed effect was attributable to parasite discovery and research effort rather than to urban adaptation status, and urban-adapted species in fact hosted fewer zoonotic parasites than expected on the basis of their total parasite richness. We conclude that extended historical contact with humans has had a limited impact on zoonotic parasite richness in urban-adapted mammals; instead, their greater observed zoonotic richness probably reflects sampling bias arising from proximity to humans, supporting a near-universal conflation between zoonotic risk, research effort and synanthropy. These findings underscore the need to resolve the mechanisms linking anthropogenic change, sampling bias and observed wildlife disease dynamics.

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Fig. 1: Urban-adapted mammals have more known parasites and zoonoses specifically.
Fig. 2: Citation numbers are higher in urban species and drive observed parasite and zoonotic parasite richness.
Fig. 3: Path analysis revealed that urban-adapted mammals do not have more zoonoses than expected on the basis of their overall parasite diversity.
Fig. 4: Model fixed-effect estimates and spatial effects on overall and zoonotic parasite richness.

Data availability

The CLOVER dataset is available at The VIRION dataset is available at All other ancillary data are available at

Code availability

The code used here is available at


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This work was supported by funding to the Viral Emergence Research Initiative (VERENA) consortium, including National Science Foundation grant BII 2021909.

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Authors and Affiliations



G.F.A. and D.J.B. conceived the study, and G.F.A. analysed the data and wrote the manuscript. C.J.C., L.E.C., E.A.E., R.G., S.J.R., A.R.S. and D.J.B. offered thoughts on the analysis and commented on the manuscript.

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Correspondence to Gregory F. Albery.

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Nature Ecology & Evolution thanks Luis Escobar, James Hassell and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Albery, G.F., Carlson, C.J., Cohen, L.E. et al. Urban-adapted mammal species have more known pathogens. Nat Ecol Evol 6, 794–801 (2022).

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