Bats have been the reservoir for recent disease outbreaks, including SARS and the current COVID-19 pandemic. But it's human activity that allows the virus to cross over.
Your body can be infected and fight off SARS-CoV-2 without your ever noticing.
Every time the virus copies itself it makes mistakes, creating a trail that researchers can use to build a family tree with information about where it's traveled, and when.
A recent study suggested the coronavirus could spread up to four metres. But the evidence isn't strong enough to suggest we should change social distancing advice from 1.5 metres.
The questions researchers around the world are working on day and night.
Universities and colleges around the world are closing. People are fleeing from cities. Some people are being forced to move but others must weigh the risks and ethical concerns of travel.
Currently, the number of confirmed global COVID-19 cases is doubling about every six days. At this rate, Australia's health sector will be unable to cope.
Best-case estimates suggest 40 million American adults may come down with COVID-19. But an epidemiologist explains why now is not the time to just give up.