http://ldsmag.com/ebola-and-the-destroying-angel/
1 A Word of Wisdom, for the benefit of the council of high priests, assembled in Kirtland, and the church, and also the saints in Zion—
2 To be sent greeting; not by commandment or constraint, but by revelation and the word of wisdom, showing forth the order and will of God in the temporal salvation of all saints in the last days—
3 Given for a principle with promise, adapted to the capacity of the weak and the weakest of all saints, who are or can be called saints.
4 Behold, verily, thus saith the Lord unto you: In consequence of evils and designs which do and will exist in the hearts of conspiring men in the last days, I have warned you, and forewarn you, by giving unto you this word of wisdom by revelation— (D&C 89)
(If you've forgotton you might as well read the whole thing!)