Health editor Jill Margo has this report on the speed of the South Australian virus strain, which authorities say has a very short incubation period and can make people infectious to others within one to three days after exposure:

The virus can go from one person to another, making them infectious, all within three days.

“This strain has a very, very short incubation period. When a person is exposed, it takes 24 hours or less for them to become infectious to others,” says Chief Public Health Officer for SA, Professor Nicola Spurrier.

It was important that action be taken immediately as the window of opportunity to close this was small.

Cases of this strain, so far, had minimal or no symptoms. When a case is passed on, it known as a generation and with this strain, a generation is three days.

“In SA we have done contact tracing to the fourth generation but the fifth generation is out there in our community. At the moment we are contact tracing to get onto that for generation," she says.

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