The World Health Organisation team in China investigating the origins of Covid-19 say they've ruled out no scenario for its first outbreak.
They’ve been visiting hospitals and markets in Wuhan to work out how the pandemic started.
Peter Daszak is from the W-H-O and says they're getting closer to finding out what happened.
But he has warned, they've a difficult job ahead of them.
"We're not only chasing the impossible, which is trying to find patient zero.
"What you're also trying to do is you're trying to say what was happening around the time of the first people to get infected that allowed that to happen, and it's all gone - you're looking back on history, really."
