TORONTO -- The Metro Toronto Convention Centre should have been bustling Wednesday with guests at a two-day retail, marketing and technology conference, but the event's plans changed with news that a Sudbury man who visited the venue last week had contracted a novel form of coronavirus.

DX3 organizers said Wednesday that they had cancelled the second day of their annual event after learning that Ontario health officials are investigating whether the man who contracted COVID-19 and attended the Prospectors and Developers Association in Canada Convention (PDAC) at the centre in early March is evidence of the country's first instance of community spread of the virus.

DX3 organizer Hifazat Ahmad said he had been debating cancellation for weeks, but moved ahead with the conference on Tuesday because he didn't think Toronto was a "major hub" for COVID-19. However, the public health announcement a day later changed his mind.

"We were inundated with messages and emails from potential participants in the last seven or eight days. We had two exhibitors pull out ... We had about 10 or 15 speakers pull out because their companies had travel restrictions or they couldn't be at large gatherings," DX3 organizer Ahmad told The Canadian Press.

"When the (PDAC) news came out...the safety of my colleagues and our team and our clients was a paramount issue. I thought the prudent thing to do was to shut shop and not risk anything else."

Deciding when to pull the plug on major corporate events isn't an easy decision, but it's one that organizations are increasingly being forced to make, sometimes within a short window of time.

The federal government has yet to ban mass gatherings, but its website says organizers need to consider the outbreak in their event planning and should consult with public health authorities.

"Mass gatherings can have the potential for serious public health consequences if they are not planned and managed carefully. They can increase the spread of infectious diseases and cause additional strain on the health care system when held during outbreaks," the site warns.

"Infections can also be transmitted during transit to and from an event, and in participants' home communities upon return."

PDAC released a statement on Wednesday afternoon saying it was "supporting" the investigation.

It highlighted safety precautions PDAC undertook like increased sanitization of high-contact surfaces, including door knobs, door handles, railings, escalators, touch-screen monitors and microphones. It also increased access to hand sanitizer and signage throughout the conference floor reminding attendees of appropriate hygiene procedures.

In making his decisions, Ahmed kept an eye on public health authority and government advice, but says he wishes both had provided more information on how to proceed with conferences, especially given how many people's health and how much money is at stake.

"That would have made life so much easier for people like me," he said.

DX3 is not the first Canadian conference called off in the wake of the virus. Ottawa-based e-commerce company Shopify Inc. cancelled its annual Unite conference that has brought hundreds of people to Toronto in each of the last two years. International technology conference Collision, which is attended by about 30,000 every year, decided to move its festivities online and stop its week-long, June event in the city.

Calgary-based Enbridge Inc. announced Tuesday that it would go online-only for its annual meeting in May "out of an abundance of caution" and to mitigate risks to the health and safety of shareholders, employees and stakeholders.

Laurentian Bank Securities said Wednesday that it had made the "difficult" decision to cancel its institutional investor conference at the start of April.

Nonetheless, other events are expecting to continue as planned. Women in Capital Markets (WCM) hosted Bank of Canada governor Stephen Poloz last week for a luncheon that filled a ballroom at the Fairmont Royal York Hotel in the city. A day later, Finance Minister Bill Morneau was in the same room to deliver a speech to an audience packed with banking and other business executives.

WCM president Camilla Sutton said in an email that when deciding to go ahead with the event, her organization looked to the federal government, the World Health Organization and Health Canada for advice.

"It is a very complicated situation," she said. "Obviously the health and safety of everyone in attendance was of concern."

WCM wrote to all attendees and asked them to reach out if they had any symptoms or had travelled to high risk regions in the last two weeks. It also encouraged people not to shake hands and had "a ton" of hand sanitizer at the event that were "bought at inflated prices."

It has since decided to only proceed with events with 20 or fewer people and to reschedule its April gala for late June. WCM is also exploring video conference options.

Conseil des relations internationales de Montreal, which is due to host a handful of events over the next few months with federal and provincial ministers, had to yet to cancel anything, said spokesperson Dominique Boisvert.

"We're going a little day to day, because of the evolving international situation," Boisvert said. "Everything is as is for the moment. Of course, nobody knows the future."

Marie-Helene Primeau of the Montreal-based risk management company Premier Continuum said she's been fielding plenty of questions from organizations she provides consulting services to.

They want to know if they should allow employees to attend events, which she said want to continue but not put anyone at risk.

"Companies want to be on the safe side and not send people over to conferences," she said. "I think we'd rather be on the cautious side."

With files from Christopher Reynolds in Montreal

This report by The Canadian Press was first published March 11, 2020.