To add to the comment about the plague not being viral: they even name it correctly at one point, Yersinia pestis, so it's definitely bacterial. It's one thing for the news anchor to get it wrong; quite another for Nathan, who is heavily involved, to do so.
While Joe works on Kathy's Macbook, the Apple logo is turned off. The Apple logo can't be turned off without turning off the display, as it is the same light source.
At one point a text is sent with an address that ends in "North West". First, that would be "Northwest" in DC. Second, nobody but nobody would ever spell it out: it would "NW". Especially in a text.