South Australian health authorities say testing of Adelaide’s wastewater has returned a “very strong” positive result for COVID–19.

SA Health says the result is still being investigated, with the detected virus possibly coming from a medi-hotel resident or an old case who is still “shedding”.

But Deputy Public Health Officer Chris Lease said it was a timely reminder that people with symptoms should be tested, with numbers dropping in recent times.

Dr Lease said the “very strong reading” came from the north-eastern part of Adelaide’s CBD, north of Pirie Street — an area where 12,000 people live or work.

The Pullman medi-hotel is in the area but the Tom’s Court Hotel, where positive COVID–19 patients are taken, is not.

The city is currently celebrating the Adelaide Festival, the Fringe festival and WOMADelaide, with authorities reminding people to ensure COVID-safe practices while attending these events.

“It’s important for people to not only monitor symptoms quite closely and not to attend [events] or go out, but to stay home and get tested.”

He said another sample would be taken on Sunday night and the result would be announced on Monday.

He said the case could be from someone from interstate who had the virus a while ago, but there was no room for complacency.

“If we can take this seriously — and I hope that we find ourselves in a positive situation that it’s an old case — but we can’t rely on that, so it’s really down to everyone to stay COVID-safe and use this as a reminder of that,” Dr Lease said.

People with symptoms not getting tested

There were no new cases reported in South Australia on Sunday.

Three active cases remain in medi-hotels, the last reported on Wednesday.

More than 2,200 people were tested for COVID-19 yesterday.

That compares with more than 17,000 a day who were tested during November’s Parafield cluster.

Dr Lease said a recent survey had found more than 70 per cent of South Australians with coronavirus symptoms, such as a cough or a fever, were not getting tested.

Health Minister Stephen Wade urged people to get swabbed if necessary.

“It’s really important that South Australians continue to do the good work that they’ve done throughout this pandemic,” he said.

Positive signs of coronavirus were detected in wastewater at Bolivar and Angaston in September but no cases without an unknown source were found as a result.