The investigation into the origin of the Canberra outbreak of COVID-19 has been widened, with contact tracers asking some people who have contracted the virus about their movements two weeks before the first case was found.
Eight of the 176 cases in the outbreak are still under investigation, including the first identified case.
The ACT reported nine new cases of COVID-19 on Wednesday, with eight linked to known cases or clusters. One case was under investigation.
Deputy chief health officer Dr Vanessa Johnston said sources for eight cases had not been found after significant investigation.
"And some of those are the index cases, or the first cases, of some of the clusters we've been talking about. We still don't have the source for the index case to this whole outbreak," Dr Johnston said.
Canberra-based author Sonya Heaney said her parents, who live in Gowrie, had tested positive for COVID-19, but contact tracers had so far been unable to connect them with any other known cases.
Ms Heaney said her father, 74, tested positive on Monday evening, after becoming symptomatic at the weekend.
"He first got a call to tell him the positive result and to check on his health. About five minutes later he got a call from a contact tracer," Ms Heaney said.
"They spent a long time going through everything he had done for the past two weeks, but still couldn't link him to any known exposure sites. There were a few more calls that evening, about contact tracing and about our living situation and who was sick.
"They have called every day since, because my family is still a mystery cluster. They apologised and said they'll be calling every day until they figure it out."
Ms Heaney said her mother, 69, was told she had tested positive for COVID-19 on Wednesday morning, and her mother and father were moved to quarantine accommodation on Wednesday afternoon.
"My mother and I got tested yesterday. I got a negative result last night, but when my mother didn't also get a text we immediately locked ourselves in separate rooms and sanitised everything. They always phone you if the result is positive - and she got that call this morning," she said on Wednesday.
Ms Heaney said ACT Health had been in constant contact with her and her parents, and were able to quickly identify everyone connected with a positive case.
"ACT Health were all over it from the start. We are, though, that unfortunate mystery cluster that's getting reported in the press conferences," she said.
"We're the 'under investigation' family. Nobody has a clue how any of us could have caught it."
Ms Heaney said the furthest her family had been in the past few months was to dinner with an extended family member in Queanbeyan.
"We were pretty ready for this. Maybe I was pessimistic, but we'd already stocked up on things and had mountains of masks and sanitiser. But apparently if you're going to get this virus, you're going to get it, no matter how much of a hermit you are," she said.
Ms Heaney said she had already bunkered down before the outbreak was first reported on August 12, avoiding going out and having groceries delivered.
She moved back in with her parents when the lockdown began.
"Of course, I'd spent a couple of weeks around my parents, no masks or anything. We were shocked about my negative test, but I'm fully expecting the next one to be positive," Ms Heaney said.
Dr Johnston said the ACT continued to complete case interviews within 24 hours of a positive test being notified, which was the national standard.
The deputy chief health officer said contact tracers from Western Australia and Tasmania were supporting a bolstered local team.
"We're prioritising those close and social contacts to call first and then those contacts that are from those transmission sites," Dr Johnston said.
"With just so many, it's increasingly challenging to be able to call all of those contacts, but everyone is getting the message and their directions as to what to do via SMS and email, to what their requirements are under the public health direction."
Dr Johnston said ACT Health was working with about10,800 close contacts and 5500 casual contacts across more than 400 exposure times and locations.
Ten sites have now been identified as transmission locations, after two cases were linked to the Reid campus of the Canberra Institute of Technology.
Ten cases have been linked to the Bright Bees Childcare Centre in Nicholls, but Dr Johnston declined to provide a breakdown of the ages of cases. Both children and adults had become infected with COVID-19 at the site, she said.
Forty cases had been associated with the cluster at Lyneham High School, the outbreak's largest. Meanwhile, 31 cases have been linked to the Fiction nightclub, the first identified exposure site.
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