Smith's Bible Dictionary (1863)
—Like the cholera, it is most violent at the first outbreak, causing almost instant death. Great difference of opinion has obtained as to whether it is contagious or not. It was very prevalent in the East, and still prevails in Egypt. Several Hebrew words are translated “pestilence” or “plague” but not one of these words call be considered as designating by its signification the disease now called the plague. Whether the disease be mentioned must be judged from the sense of passages, not from the sense of words.
Those pestilences which were sent as special judgments, and were either supernaturally rapid in their effects or were in addition directed against particular culprits are beyond the reach of human inquiry. But we also read of pestilences which, although sent as judgments, have the characteristics of modern epidemics, not being rapid beyond nature nor directed against individuals. (Leviticus 26:25; 28:21) In neither of these passages does it seem certain that the plague is specified. The notices in the prophets present the same difficulty.
Hezekiah’s disease has been thought to have been the plague, and its fatal nature, as well as the mention of a boil, makes this not improbable. On the other hand, there Is no mention of a pestilence among his people at the time.