A Covid alert has been issued for 25 Melbourne suburbs after fragments of the virus were found in wastewater samples across the city.
Victoria’s Health and Human Services said three positive results were found on Thursday afternoon at treatment plants in Pascoe Vale, in the city’s north, and Scoresby and Vermont, east of Melbourne, which cover dozens of suburbs between them.
The department listed the new results as 'unexpected detections', as no residents in those suburbs had tested positive for the virus.
The detection may be from someone who had Covid and is no longer infectious or an active but undiagnosed infectious case, health officials said.
Anyone living in or visiting the following 25 suburbs between June 3 and June 7 is being urged to monitor for symptoms and get tested if they develop.
Glenroy, Hadfield, Oak Park, Pascoe Vale.
Burwood East, Forest Hill, Glen Waverley, Scoresby, Vermont South, Wantirna South, Wheelers Hill.
Balwyn, Balwyn North, Blackburn, Blackburn, North, Box Hill, Box Hill North, Bulleen, Doncaster, Doncaster East, Donvale, Mitcham, Mont Albert, Mont Albert North, Nunawading
On Wednesday, Covid fragments were found in a wastewater plant serving suburbs north-west of Bendigo.
The news comes after strict lockdown restrictions for Melbourne were eased, despite four new infections from a mystery source.
Deputy Chief Health Officer Allen Cheng said the cases were not existing primary contacts and had not visited any of the exposure sites identified from previous cases.
Prof Cheng said the locally acquired infections were a man in his 80s, a woman in her 70s, a man in his 50s and a man in his 20s, all from the same Reservoir household in Melbourne's north.
The Department of Health's testing chief Jeroen Weimar said the cases are a "new cluster".
He asked Melburnians to check the list of exposure sites associated with the household which includes Coles at Bundoora Square, and Bunnings in Thomastown.
Masks stay as Melbourne ends lockdown
Masks will remain compulsory in Melbourne while other restrictions will ease as planned.
Acting Premier James Merlino confirmed restrictions will ease at 11:59pm on Thursday, but Melburnians must continue wearing masks indoors and outdoors.
"It is inconvenient but an easy thing to do. We are used to it, we know it works," he told reporters on Thursday.
"As we come out of this period of lockdown, while we are driving these new cases to ground, it is a logical and common-sense step to take."
Deputy Chief Health Officer Allen Cheng said masks had proven to be effective at limiting the spread of coronavirus during the state's second wave.
"It's just a small thing we can do to help prevent infection as everything else starts to move again," he said.
While conceding transmission is 20 times less likely to happen outdoors, Professor Cheng said it "doesn't mean it's zero".
"There is still a risk and there have been transmissions documented outdoors," he said.
Do you have a story tip? Email: email@example.com.