Adelaide positive COVIDâ19 wastewater test from undetected infection or old case, SA Health says Posted TueTuesday 9 updated WedWednesday 10 Adelaide's Fringe festival is in full swing in the city. ( Print text only Cancel South Australian health authorities say a positive COVID-19 result in wastewater from Adelaide's CBD is either from an undetected case in the community or shedding from an old infection. Key points: SA Health says it is either from an undetected case or an old case The state has today recorded one new case of COVID-19 in a returned traveller Deputy Chief Public Health Officer Emily Kirkpatrick said further testing had ruled out that the result was not a mistake and it did not come from a returned traveller or a medi-hotel worker.