he has a virus, but seems that it is asymptomatic, if i heard it well
He likely contracted the virus recently, and most people do not start to show symptoms right away.
maybe they will postpone elections, do not know about the procedure, but that seems as rational idea, and probably there is some clause that "due to higher cause" elections could be postponed by month/two, and until then everything will probably be back to normal
Trump does not have the authority to unilaterally postpone the election. Only Congress can change the election date, and the results must be in by December 14, as the constitution perscribes this to be the date the electrical college meets to cast their votes.