Seventeen coronavirus cases have now been linked to a cluster in Adelaide’s northern suburbs, South Australia’s Chief Public Health Officer says.

Nicola Spurrier said the Port Adelaide Hungry Jack’s has closed because a staff member worked there while infectious.

Mawson Lakes Primary School and Preschool and the Parafield Plaza Supermarket have also closed.

Thomas More College in Salisbury Downs also announced it was closing today because of a positive coronavirus case.

A small shopping centre with a tower
The 80-year-old woman visited Adelaide’s Parafield Plaza Supermarket on Thursday morning.(ABC Radio Adelaide: Spence Denny)

SA Health yesterday said an 80-year-old woman tested positive after being treated at the Lyell McEwin Hospital in the city’s north.

She had visited the supermarket on Thursday.

Two of her close contacts — a woman in her 50s and a man in his 60s — have also tested positive for the illness.

An employee of the Yatala Labour Prison was also diagnosed.

Two of the new cases worked while infectious at an aged care facility that Dr Spurrier would not name.

Premier Steven Marshall said hundreds of people connected with the cases were now in isolation.

“We’ve got very, very good cooperation from all the people that have that has been interviewed by the Communicable Disease Control Branch.”