Zoonotic disease and virome diversity in bats

The emergence of zoonotic viral diseases in humans commonly reflects exposure to mammalian wildlife. Bats (order Chiroptera) are arguably the most important mammalian reservoir for zoonotic viruses, with notable examples including Severe Acute Respiratory Syndrome coronaviruses 1 and 2, Middle East Respiratory Syndrome coronavirus, henipaviruses and lyssaviruses. Herein, we outline our current knowledge on the diversity of bat viromes, particularly through the lens of metagenomic next-generation sequencing and in the context of disease emergence. A key conclusion is that although bats harbour abundant virus diversity, the vast majority of bat viruses have not emerged to cause disease in new hosts such that bats are better regarded as critical but endangered components of global ecosystems.