"PATIENT ZERO"
Health authorities are struggling to work out how the outbreak started.
The first cases were announced only on Friday and doctors do not know the source of the illness.
Initial suspicion in Lombardy fell on a businessman recently returned from China, the epicentre of the new virus, but he has tested negative. In Veneto, doctors tested a group of eight Chinese visitors who had been to the town that was home to the first fatality, but again, they all tested negative.
"We are (now) even more worried because if we cannot find 'patient zero' then it means the virus is even more ubiquitous than we thought," said Veneto regional governor Luca Zaia.