Global patterns in coronavirus diversity

Anthony, Simon J.; Johnson, Christine K.; Greig, Denise J.; Kramer, Sarah; Che, Xiaoyu; Wells, Heather; Hicks, Allison L.; Joly, Damien O.; Wolfe, Nathan D.; Daszak, Peter; Karesh, William; Lipkin, W. I.; Morse, Stephen S.; Mazet, Jonna A. K.; Goldstein, Tracey

It is important to note that we distinguish 'host switching' (inter-genus or family switching) from 'sharing' (intra-genus switching) in our analysis and that while the proportion of host switches was lower in Latin America, the proportion of sharing events was concomitantly higher. This indicates that CoVs in this region still switch hosts, just like they do in Africa and Asia, but that they preferentially move between closely related species. While we do not yet understand the factors driving this difference, if we assume that the risk of spillover to humans reflects the taxonomic distances that CoVs are able to jump (Kreuder Johnson et al. 2015) , our results would indicate a higher risk for zoonotic emergence in Africa and Asia [acknowledging that host switching is not the only important factor driving zoonotic emergence (Jones et al. 2008; Keesing et al. 2010; Karesh et al. 2012) ]. While evidence of regional variation in host switching has not been reported previously for viruses (to our knowledge), similar patterns have been observed in hemosporidian parasites (Ellis et al. 2015) .