December 10, 2013; 8:29 PM ET
The coldest air of the season will settle into the Washington, D.C., area at midweek, followed by another storm this weekend. more >
Snow Saturday will accumulate less than an inch before changing to rain
The sheer number of people, their interactions with animals and ecosystems, and the increase in international trade and travel are all factors that will likely change the way humanity deals with preventing and treating epidemics, experts say.