A website operated by Johns Hopkins Center for Systems Science and Engineering pulls together data from the World Health Organisation, the U.S. Centers for Disease Control as well as health authorities in Europe and China.
As of 8:50 PM Eastern time on Monday, there were 4,474 confirmed cases, mostly in mainland China, with 5 confirmed cases in the United States. The number of cases in China is expanding rapidly.
Thanks to CNET for bringing this to my attention via a post.