Inferring the ecological niche of bat viruses closely related to SARS-CoV-2 using phylogeographic analyses of Rhinolophus species

The Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) is the causal agent of the coronavirus disease 2019 (COVID-19) pandemic. To date, viruses closely related to SARS-CoV-2 have been reported in four bat species: Rhinolophus acuminatus, Rhinolophus affinis, Rhinolophus malayanus, and Rhinolophus shameli. Here, we analysed 343 sequences of the mitochondrial cytochrome c oxidase subunit 1 gene (CO1) from georeferenced bats of the four Rhinolophus species identified as reservoirs of viruses closely related to SARS-CoV-2. Haplotype networks were constructed in order to investigate patterns of genetic diversity among bat populations of Southeast Asia and China. No strong geographic structure was found for the four Rhinolophus species, suggesting high dispersal capacity. The ecological niche of bat viruses closely related to SARS-CoV-2 was predicted using the four localities in which bat viruses were recently discovered and the localities where bats showed the same CO1 haplotypes than virus-positive bats. The ecological niche of bat viruses related to SARS-CoV was deduced from the localities where bat viruses were previously detected. The results show that the ecological niche of bat viruses related to SARS-CoV2 includes several regions of mainland Southeast Asia whereas the ecological niche of bat viruses related to SARS-CoV is mainly restricted to China. In agreement with these results, human populations in Laos, Vietnam, Cambodia, and Thailand appear to be much less affected by the COVID-19 pandemic than other countries of Southeast Asia. In the climatic transitional zone between the two ecological niches (southern Yunnan, northern Laos, northern Vietnam), genomic recombination between highly divergent viruses is more likely to occur. Considering the limited data and the risk of recombinant bat-CoVs emergence as the source of new pandemics in humans, the bat populations in these regions should be under surveillance.