South Australia has introduced a strict lockdown for the next six days, in a bid to quickly crush a cluster of 22 known infections in Adelaide.
Health authorities are concerned that the city might be contending with a particularly insidious and virulent strain of the virus.
The state's chief health officer, Nicola Spurrier, says the strain appears to have an incubation period of only 24 hours, with people becoming infectious more quickly than elsewhere.
The ABC's Gabriella Marchant speaks to Corin Dann from Adelaide.
