The many images on social media of medical workers in China apparently overwhelmed by an influx of cases of a new strain of coronavirus are, without doubt, alarming. And world health authorities’ concerns about the global transmission of this potentially fatal virus are entirely justified.

Chinese President Xi Jinping has described the situation as grave and warned that the spread is accelerating. For a nation notoriously averse to conceding any weaknesses, that is a very significant admission.

Isolating the city of Wuhan, the centre of the outbreak, has apparently not halted this particular coronavirus, known as 2019-nCoV. Less than two weeks ago, there were just a few dozen cases, mostly limited to Wuhan.

Now there are almost 2000 confirmed cases worldwide, according to China’s state media. Thirteen other countries have less than a handful of cases each.

Australian health authorities are managing four confirmed cases of 2019-nCoV, in Sydney and Melbourne. They are seeking to contact all passengers who were on the same airline flight from Wuhan as one of those patients.