CALGARY -- In the latest reminder of the need to avoid public spaces, a retail employee at Southcentre Mall has been diagnosed with a presumptive case of COVID-19.

The mall says other employees of the store have been told, along with neighbouring businesses.

The store has been closed and on Thursday afternoon, only a handful of stores remained open.

Cleaning has been stepped up in the mall and staff were seen wearing masks pushing carts loaded with paper towels and spray bottles of cleaner.

Anyone who has shopped at the mall recently should take extra care to monitor their health and avoid contact with any more people than absolutely necessary.

People infected with COVID-19 often show no symptoms for up to 14 days.

An Imperial College study showed the average infected person will pass the virus to between two and three other people.

The social distancing being pushed by public health officials is aimed at getting that number to less than one.

Because of the delay in showing symptoms, it will take at least two weeks for the effects of social distancing measures to show up in the number of new cases reported.