Health authorities are investigating two new cases of coronavirus in the ACT where it is not known how the patients acquired the virus.
It comes as the total number of cases in the ACT rose to 103, after three new cases were confirmed in the past 24 hours.
The new cases include two women and one man, aged between 26 and 51.
One acquired the case from a previously confirmed case.
However, work is under way to determine how the remaining two new cases acquired coronavirus.
One of the cases under investigation is an intensive care unit nurse at Canberra Hospital, but health authorities say they believe the nurse acquired it through a close contact at home and not from a patient at the hospital.
Deputy chief medical officer Paul Kelly was asked about the case of the intensive care nurse, and whether she could have caught the virus from a patient, but said the investigation was at an early stage.
"It is difficult at the beginning of such an investigation to decide where that source might have been," professor Kelly said.
"My understanding of that particular case is that, that person's partner had returned from overseas with symptoms, which, which were similar to COVID patients, whether they've tested positive or not, I don't have that information at the moment, but that that case is still being investigated."
A small number of Canberra Hospital staff members were identified as close contacts of the nurse and required to self-quarantine.
The other case under investigation is not linked to the intensive care nurse and is not linked to Canberra Hospital. The patient was tested because they met the existing criteria for testing, not as part of the increased random testing of people who are symptomatic.
There are now four patients who are in Canberra Hospital.
ACT Health says 59 patients have recovered from coronavirus.
The remaining number of cases are self-isolating at home.
There are three cases of coronavirus in the ACT that are under investigation.
More than 6000 negative tests for coronavirus have been carried out.
Despite the increase in cases under investigation, ACT health officials say there still has been no evidence of community transmission in Canberra.
However, the number of random tests being carried out at the Weston Creek walk-in centre and the drive-thru testing clinic at EPIC will be expanded further.
Increased testing for coronavirus has been in place in Canberra since Monday, after a drop in the number of people arriving back home from overseas.
Acting ACT chief health officer Dr Vanessa Johnston said the increased testing would try and investigate potential community transmission.
"Community transmission is when we start to see a large number of locally acquired cases where a direct source of exposure cannot be identified," Dr Johnston said.
"Although we still have three cases under investigation we have not seen any evidence of this so far in the ACT. This is despite actively looking for it by testing members of the community who have no history of overseas travel or contact with known confirmed cases.
"For several weeks this group has included symptomatic healthcare and aged-care workers, as well as people who live and work in high-risk settings.
"Since April 6, this has also included a random sample of people who present to designated clinics who are symptomatic but do not otherwise meet the criteria."
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