LONDON, ONT. -- The Grey Bruce Health Unit is declaring a 'critical threshold' as it reports more than 70 new COVID-19 cases and is now asking all residents to stay home for the next two days.

The advisory is on top of Ontario's already existing stay-at-home order as the health unit wants every resident to consider themselves a carrier for the next 48 hours in order to slow the spread of COVID-19 in the community.

On Thursday morning CTV's Scott Miller reported that several businesses were voluntarily closing over the next two days to help with the advisory.

In a media release issued Wednesday afternoon, the health unit said, "This is a significant situation requiring a Grey Bruce-wide response, otherwise the pandemic locally will potentially spiral out of control. Drastic measures are required and will be implemented imminently."

In addition to 25 cases being added to the region's total on Wednesday, health officials say they have also received a report of an additional 48 cases.

"We have identified over 70 new confirmed cases across Grey Bruce in the last thirty-six hours with the potential to generate hundreds of additional close contacts," said Medical Officer of Health Dr. Ian Arra in a news release.

There are currently 111 active cases in Grey-Bruce, with half of those concentrating in Owen Sound and the Town of Blue Mountains. Despite the concentration, viligance is being urged across the entire region.

Even with just 25 cases confirmed Wednesday, it was the highest single-day total for the region since the start of the pandemic. The last spike, reported on Jan. 6, was 20 cases.

The cases include 99 variants of concern and officials say there are 498 high-risk contacts.

"The sources of transmission are identified as individuals not following lockdown with people visiting others when symptomatic as well as social gatherings and ‘bush parties’ by high school-aged youth. The issue is worsened by individuals being untruthful to public health contact tracing and case management inquiries," said Arra.

The Municipality in Kincardine is closing all its municipal facilities until Monday. Meanwhile Bruce Power, the region's largest employer with more than 4,000 employees, is urging any employees who can work from home to do so over the next two days.

Saugeen Shores Mayor Luke Charbonneau says he's impressed with the community's quick response.

"I'm buoyed by it, but not surprised by it. I never had any doubt that our community and citizens would step up and do what had to be done in the moment to mitigate the spread."

Health unit staff are being redeployed from other programs, including the vaccine program and helpline, in order to support contact tracing and case management.

A mass vaccination clinic is being cancelled this Saturday in order to move staff to help with contact tracing, and the healh unit is considering cancelling clinics next week as well.

"If they (the health unit) feel they need to redeploy resources to contract trace and step back on vaccines for the very short term in order to stop the surge, then I have confidence they are doing the right thing and the public should have confidence they around doing the right thing," says Charnonneau.

Arra stressed the importance of every resident staying home.

"Everyone across Grey Bruce needs to consider themselves a carrier for the next 48 hours until we reach all case and their contacts. It is a priority that everyone stay at home except for essential travel. If contacted by public health, be prudent in following any direction that is given. This is in addition to the provincial stay-at-home order."

A class action order from the medical officer of health will also be issued to further reinforce the need for cases and close contacts to follow public health direction.

Two outbreaks were confirmed in the region on Tuesday.

One is at Queen of Hearts Nursery School in Owen Sound, which has three confirmed and several probable cases, and another Georgian Bay Community School in in Meaford, where five confirmed cases and one probable case have been reported.

The health unit says it has reached out to anyone identified as a close contact in both outbreaks.

Prior to the province-wide saty-at-home order, Grey-Bruce had very few COVID-19 cases and was in the green-prevent zone of Ontario's COVID-19 response frameworks.

- With files from Amanda Taccone and reporting from Scott Miller