Sherrie Mae Guthrie dropped off her son at Muskoka Woods Camp at around 3 p.m. Sunday. More than two hours later, she got a call to pick him up.

There's COVID-19 in the camp, Beckett told his mom through the phone.

Guthrie was among the many parents who had to scramble back to the Rosseau, Ont. camp after a COVID-19 outbreak was declared.

In a statement issued Monday, Muskoka Woods Camp said they initially identified "single digit" cases with one cohort on Saturday, the end of the camp's week 4.

However, another case was discovered "through rigorous testing protocols" as week 5 guests arrived Sunday, prompting the Simcoe Muskoka District Health Unit to declare the outbreak.

"With the health and safety of our guests and staff being our top priority, we made the decision to cancel Week 5. We continue to follow all Public Health protocols and are working closely with them on a date when we can reopen," the statement read, adding that those who tested positive were no longer on-site.

John McAuley, the president and chief executive officer of the camp, added, "Our hearts are aching for all the kids who missed out on everything that summer camp has to offer."

The camp opened its door to guests on July 4.

Overnight camps in Ontario were allowed to open under strict protocols when the province moved into the second phase of its reopening plan in early July.

Under the final protocols laid out by the province, campers are required to stay within cohorts, self-isolate 14 days before arrival and be screened and tested for the virus while at camp, among other things.

Guthrie told CTV News Barrie that she chose the camp because it has been very transparent about its COVID-19 policies and procedures.

"Two weeks ago, they asked us to ensure that we were self-isolating so that we weren't really around too many people to ensure the safety of all the campers which we followed," she said.

Guthrie also noted that they had to take a PCR test three days before camp to ensure that they are COVID-19 free.

She was first informed about the positive cases at the camp the night before when she received an email from management.

"When we arrived at camp, in the queue, they informed us that there was COVID, and public health unit was involved. But at this point in time, the camp was not closed," she said.

"About 5:45 p.m., I received a phone call from Beckett telling us that his counsellor had told him that there's COVID in the camp, and I needed to come and get him."

Guthrie said they arrived back at camp around 8 p.m. and picked up Beckett. They got home around midnight.

Beckett said when the counsellor first informed him about the cases, he thought he was joking.

"He was a very funny person. So, he told us, the camp was closing. We all thought it was a joke. And then we saw people like counsellors were outside and like officials were coming in. So, then we realize it wasn't a joke," Beckett said.

"...we were kind of worried that well some of us might get COVID, some of us may not. We weren't sure what would happen.

Guthrie said she has asked that her son be put on the camp's waitlist, hoping that Beckett can go to camp in another week.

"Beckett's been stuck at home with his family and two older sisters for the past two years. So, he needs to go out and play and have fun and be outside," she said.

"I think it's good for his social well-being, mental well-being and for him just to be a regular Canadian kid for a week this summer."

Dr. Isaach Bogoch told CP24 Monday that it is not surprising to hear about a handful of outbreaks at some summer camps.

"You imagine that the protocols in many of the summer camps might be fantastic and might be very strong, but they're only as good as how well they are adhered to. And if there's any slip-up, you know, that there's pretty much very little room for error here. If this virus is introduced, it's just going to spread. And that's probably what happened here," Bogoch said.

"Fortunately, we haven't heard of a ton of outbreaks in these summer camps. So, this is largely likely reflective of low burdens of COVID-19 here in Canada, and also the summer camps generally adhering to these protocols."

- with files from CTV Barrie's Kraig Krause and The Canadian Press