Sahih Muslim Book 23, Hadith Number 5001.

Chapter : Command pertaining to the covering of vessels, and tightening (the mouths) of waterskins, etc.

This hadith is reported on the authority of Laith b. Sa’d with the same chain of transmitters, but with a slight variation in wording (and that is that) he (the Holy Prophet) said: There is a day in a year when descends the pestilence; at the end of the hadith Laith said that the non Arabs save themselves from it in Kanun Awwal (this is the month of December).