The naysayers who want to downplay this as business as usual are wrong.
I have had three cases of this within two weeks at my company. Prior to that time, I have not had a single piece of Mac malware infect my machines over a period of 8 years.
This is not business as usual. I expect to find a whole lot more of this in the near future, and for the first time since I've managed IT at this company, I'm researching anti-malware solutions for Mac.