KITCHENER -- Southwestern Public Health officials are investigating a COVID-19 outbreak at a congregate living setting in the region.

Officials said at least 31 people have tested positive for the disease in relation to the outbreak.

One person was admitted to hospital on Oct. 30 for treatment for COVID-19 symptoms. They remain in hospital, health officials said.

Southwestern Public Health said anyone living at the congregate setting and close contacts have been tested for COVID-19. They are still waiting for some results from a total of 157 tests.

The sharp rise in cases came as a shock to the small community. Mayor Ed Ketchabaw said the outbreak was unexpected.

"We haven't had an infection in Bayham since August 25th," he said. "We've had relatively low infection rates for the last couple of months."

Kevin Martin with Martin's Fruit Farm confirmed to CTV News that the outbreak is at Vienna Farms, one of the company's orchard facilities. He said farm officials learned about a positive test on Friday and tested everyone at the site.

Martin said the cases are in migrant and local workers.

There isn't a food stand at the premises and workers will likely finish their apple harvest over the next few days.

Martin said the company is working closely with public health officials to identify and isolate positive cases.

"We're just concerned about health and safety," Martin said. "We're working very closely with public health and isolating any positive cases."

Some of the workers live on-site.

"We've been following public health requirements and they would live in bunkhouses, so there would be some sharing rooms," Martin said.

“We are still investigating and will share more details when they are available,” Dr. Joyce Lock, Medical Officer of Health at Southwestern Public Health, said in a news release. “Everyone is reminded to keep practicing physical distancing, handwashing, wearing a face covering, and stay home when feeling unwell, to help stop further spread in our communities.”

The health region is reporting 29 active cases of COVID-19, and officials said some of the outbreak cases haven't been added to the dashboard. There have been a total of 337 lab-confirmed cases of the virus to date.

The majority of active cases are in Bayham and Woodstock.

Ketchabaw said he's satisfied with the current health guidelines for agri-food facilities that employ seasonal workers.

"You've got many more people in a school setting, just as you do in a bunkhouse facility," he said. "They're coming in from someplace and all it takes is one incident."

Martin's Family Fruit Farm also has a location in Waterloo, but said the staff there haven't been impacted by the outbreak.

Five people have died from COVID-19 in the area.

Officials said there will likely be a jump in positive cases in the coming days.

With reporting by CTV News Kitchener's Krista Sharpe and Tegan Versolatto