Health authorities in Sydney, Australia have issued a Covid-19 public health alert after diagnosing the first cases of community transmission since December 3.
Five community cases of Covid-19 have been discovered in Sydney since Wednesday, according to New South Wales' health department.
Just one of the five cases can be traced -- a 40-year-old bus driver who ferried airline crews to and from their hotels.
The four mystery cases are all located in Sydney’s Northern Beaches area. Two were diagnosed on Wednesday and a further two on Thursday.
Residents in the area responded to a call for increased testing with long queues at clinics on Thursday morning.
“We encourage everybody who lives on the Northern Beaches with the mildest of symptoms to come forward and get tested," New South Wales Premier Gladys Berejiklian said Thursday. "We really want to get on top of this."
The Berejiklian government took the added step on Thursday of canceling visits for elderly care homes on the Northern Beaches.
"We're recommending no visitors until we identify the source of infection and feel more confident that we have it under control," she said.
New South Wales has recorded a total of 4,477 cases of Covid-19 since the beginning of the pandemic, according to the local health department.