Public Health England says there are now four confirmed cases of coronavirus in North Yorkshire.
However, health bosses are not saying where in the county the cases are.
The first case of the virus in the county was confirmed on Thursday with officials saying tests showed a North Yorkshire resident had tested positive for COVID-19.
It is understood they had recently returned from a trip to Italy and were now self-isolating.
The epidemic has already caused the cancellation of a number of public events in the region, including Welcome to Yorkshire’s Y20 conference which was due to be held in Bradford.
James Mason, chief executive of Welcome to Yorkshire, said: “This is obviously disappointing news for everyone connected with the event, including our own hard-working staff and the team at St George’s Hall who have put so much time and effort in over the last few weeks and months.
“In addition, we would like to apologise to the hundreds of people who have already registered to attend, but postponement is the right thing to do. The health and well-being of people across Yorkshire and the whole country is the priority.
“We know that tourism businesses are suffering due to this outbreak but hopefully the measures that the Government is now putting in place will see the impact lessen over time.
“We stand ready, willing and able to promote Yorkshire and its wonderful destinations and attractions, but we must act responsibly and do our bit to reduce exposure to the virus.”
The Yorkshire Choice Awards, which were due to be held in Leeds and featured a number of finalists from Richmondshire, have also been postponed due to the crisis.