Stephanie Seifert, a virus ecologist at Washington State University in Pullman who was not involved in the research, tells Nature that the work “highlights how often these viruses have the opportunity to spillover.”

The study coauthors considered the geographic ranges of bats known to host SARS-related viruses—primarily horseshoe bats (family Rhinolophidae) and Old World leaf-nosed bats (family Hipposideridae). They found hot spots of potential spillover events in southern China, parts of Myanmar, and the Indonesian island of Java—where both bat and human populations are particularly dense, reports Nature.

Most of these SARS-related viruses don’t easily spread among humans or cause illness. But study coauthor Peter Daszak tells Nature that with enough infections “raining down on people, you will eventually get a pandemic.”