During a public health emergency involving a contagious infection, it is possible – and so it is rational – to assume that some portion of that emergency lies hidden beyond one’s immediate view. This likelihood can be described simply, in this very way: some portion of this emergency likely lies hidden beyond one’s immediate view.
Update, 3.28.20: the original article linked below has been updated (with the remaining, substantially-cited portions helpfully still present). A personal note in this, sincerely offered: a thank you to the editor for the update. We find ourselves – as an entire country – in startling and difficult circumstances. We will make our way as best we can.
It is different, however, to write that “[c]omments on social media claim that reliable sources have confirmed that there are at least three persons in the city [Whitewater] who have been diagnosed.” Unlike a matter of editorial opinion, particular reportorial claims about specific public health statistics, for example, should be identified by the professional institution that offers them (a hospital, university, a government agency, etc.).
Specific numerical claims may be true, but if made, they should be made under citation.