Last week, an international collaboration that went looking for known or novel viruses in pneumonia patients in Malaysia reported that in eight children, they found signs of a coronavirus that may have originated in dogs. Earlier this year another group reported a coronavirus that appears to have jumped from pigs to several children in Haiti. There’s no sign so far that either virus can spread from person to person—as the spark of the pandemic, SARS-CoV-2, readily does—or definitive evidence that they cause human illness. But the discoveries, which could increase the number of coronaviruses known to infect people from seven to nine, underscore the threat posed by this viral family.