The 82-year-old aged care resident is now in hospital and the 11 residents under the nurse's care have been isolated as a precaution. The cases are particularly worrying, given COVID-19 is most severe in the elderly, who account for the majority of the more than 3100 deaths worldwide. The nurse has not travelled overseas recently and had contracted the virus from someone in Australia - a sign the virus has begun spreading in the community. "It is concerning when we have somebody present with coronavirus and we can't track the source," Mr Hazzard said. NSW Chief Health Officer Kerry Chant said, "This is probably a case of community exposure.

"Where she got it is not clear ... we are taking additional measures to up surveillance in that area." Loading Mr Hazzard described the employee as "a much-loved and very long-working member of the staff". "She's actually worked there at the nursing home, at the residential care facility, for more than two decades," he said. The woman worked at the lodge on February 24 when she started getting symptoms and it is likely that she could have been infectious from at least February 23, Mr Hazzard said.

She has been quarantined in Royal North Shore Hospital in a stable condition. Loading More than 80 per cent of COVID-19 deaths globally are people over 60, and more than 75 per cent had underlying conditions such as cardiovascular disease and diabetes. By Wednesday morning the total number of cases in the state rose to 15, as NSW Health released the details of five flights to Sydney that carried passengers later diagnosed with the virus. One of the infected people is a lecturer at Macquarie University from the Science and Engineering faculty. He is recovering in an isolation ward at Westmead Hospital. He became ill after returning from Iran and sought medical attention, a spokesman for the university said in a statement.

"Our staff member has not been present at Macquarie University’s campus since returning from Iran and has had no contact with either staff or students," the statement said, adding there was no evidence to suggest the case was connected to the aged care worker. Meanwhile, 75 staff from Ryde Hospital have been quarantined after coming into contact with a 53-year-old doctor diagnosed with COVID-19, including 30 doctors, 24 nurses and 21 support staff. Ten of the doctors and 21 nurses are in home isolation, NSW Health said. Eight patients have also been identified as close contacts and have been contacted by health authorities. None have reported symptoms. A total of 37 patients have been flagged as casual contacts. So far 24 have been contacted, NSW Health has attempted to contact another 11 and two are yet to be contacted.

Loading Replay Replay video Play video Play video Additional healthcare workers were brought in to ensure Ryde Hospital was fully staffed, Dr Chant said. NSW Health also released the flight details of five other people diagnosed with the virus who may have been infectious on flights to Sydney. A man in his 30s returned from Iran and arrived in Sydney on Malindo Air flight OD171 from Kuala Lumpur on March 1. He was seated in row 15 and passengers seated around him will be contacted by NSW Health. The man is being treated at Westmead Hospital.

Another man in his 30s arrived from Iran on Sunday, March 1, on a flight from Malaysia that transited through Singapore. Loading He was on Jetstar Asia Airways flight 3K686 which codeshares with Qantas QF5186 departing Kuala Lumpur on February 29 and arriving in Singapore later that day. He then flew to Sydney on Qantas flight QF82. He was seated in row 32 on that flight, which departed Singapore at 8.30pm on February 29 and arrived in Sydney on March 1 at 7.35am. A man in his 50s returned from Singapore on February 28 on Qantas flight QF02. He was seated in row five. A woman in her 60s arrived in Sydney from South Korea on Korean Air flight KE121 on February 27.

Another woman in her 60s, returned to Sydney from Japan on February 21 and was diagnosed on March 3. The details of the flight the woman was on have not been provided. NSW Health said travellers from Iran, South Korea and Japan should be particularly vigilant for symptoms as there had been a rapid increase in COVID-19 activity there in recent days. Emergency departments are bracing for a deluge of patients, with authorities predicting coronavirus outbreaks will converge with an early and severe flu season. The number of confirmed influenza cases in January and February are greater than last year’s unusually high numbers. Increasingly, patients are presenting to emergency departments and presentations for flu-like illnesses and other respiratory conditions at well above historic averages, NSW Health said.

Loading Replay Replay video Play video Play video NSW paramedics have offered to make home visits to help diagnose coronavirus and ease the strain on hospitals. "We are normally reluctant to suggest extra duties for the state’s already over-stretched paramedic workforce. However, these are not normal times," Health Services Union NSW secretary Gerard Hayes said. "Coronavirus will add massive strain to the flu season by clogging up emergency departments and medical centres. This also creates an environment for the virus to spread." The union wants these home visits to be free of charge to the public, which would be a decision made by the state government.

Loading Mr Hazzard said he was yet to speak to Mr Hayes about the offer and would follow it up. "Every suggestion is being taken constructively, positively," Mr Hazzard said. The HSU is also asking the NSW Treasurer for at least $100 million to boost the capacity of ambulances and hospitals before the start of the flu season. Globally there are 92,844 confirmed cases (48,229 of whom have recovered) and 3160 deaths.

-with Rachel Clun