What is the mystery pneumonia that killed three in Argentina?
Testing has ruled out coronavirus, influenza, hantavirus and about 30 other possible causes. Here's what we know.
Kinesiologist Maria Luz Porra puts on a mask shield before checking patients suffering from the coronavirus disease (COVID-19) in an intensive care unit of a hospital, on the outskirts of Buenos Aires, Argentina October 16, 2020. (photo credit: AGUSTIN MARCARIAN/REUTERS)
