UPDATE: This story was updated at 12:20 p.m.

Niagara's first COVID-19 patient did not acquire the potentially deadly infection by travelling abroad, Niagara's public health department says.

Dr. Mustafa Hirji said the health department is still investigating how the 84-year-old man contracted the virus, and one of the patient's family members has been isolated.

"Our working hypothesis is that the source of the infection may have been from a family member who was travelling but did not show symptoms immediately upon return to Canada," Hirji said. "That family is now showing mild symptoms so they are being tested."

Hirji said the patient was transferred to the St. Catharines hospital on Tuesday for an another medical issue, then subsequently tested for COVID-19. The test came back positive late Thursday night.

The paramedics and health care professionals who cared for the patient prior to the COVID-19 test are also being isolated as a precaution.

However, those health care worker are not being tested yet.

"You cannot really test if a person is not showing symptoms," Hirji said. "If you test right away without symptoms and it comes back negative, that negative test may not mean anything. You really have to wait until you see the symptoms."

Hirji said public health officials are working on identifying anyone else the patient came into contact with and where he may have been infected.

He said the public health department would not say if the patient is a resident of a local long term care home until such time as revealing that information is relevant. The health department is still waiting for a complete list of places and people the patient may have come into contact with from the patient's family.

The man is currently in isolation in stable condition at the St. Catharines hospital.

"Despite Niagara having its first case, there continues to be no evidence of local circulation of the virus in Niagara or Ontario," Hirji said in a statement.

"The risk to Niagara residents therefore remains low."

Local members of provincial parliament were notified of the positive result Friday morning.

The positive result comes on the heels of local health officials taking proactive steps to mitigate the spread of COVID-19 in the event of a local outbreak.

Niagara Health, which does all local testing for COVID-19 and test patients, is establishing two assessment centres to screen and test potential patients at locations away from hospitals. That's being done in a bid to reduce the possible spread of the virus.

Health system officials say it will be at least a week before they will be able to announce where in Niagara Falls and St. Catharines the centres will be set up.

Loading... Loading... Loading... Loading... Loading... Loading...

However, given the positive test, Niagara Health is stepping up its screening protocols.

According to sources familiar with the situation, some hospital entrances in St. Catharines will be closed and patients and visitors will be directed to specific entrances where they will be asked about their medical status and travel history — the basic elements of widely used COVID-19 screening.

On Wednesday, Niagara Health chief of staff Dr. Johan Viljoen said the St. Catharines hospital will be the treatment centre for all local COVID-19 cases that require hospitalization.

The Niagara case was one of a rash of new infections confirmed by the Ontario Ministry of Health and Long Term Care Friday morning.

The ministry says there are now 74 cases in Ontario, up from 54 Thursday.

This is a developing story. More to come.

- COVID-19 Q&A with Niagara's medical officer of health

- Niagara's first responders prepare for pandemic

- Niagara Health to establish two COVID-19 assessment centres