A good old fashioned plague

Sometimes when I'm out and about, and there's too many people around for my taste, I start thinking about diseases.  Horrible diseases that decimate populations in short amounts of time.  We haven't really had one of those for a while.  Not since the 1918 flu epidemic, really.  I think we're overdue for one.  I think mother nature tried to get a couple going with bird flu and west nile virus, but the WHO keeps foiling her attempts.  I'm concerned she's going to get very angry and send one we really can't control at all.  She has an ego that bruises easily.  I vote antibiotic resistant bacteria or a cold mutation will be the thing to kill off 1/3 of us.  My husband thinks it'll be a virus that creates zombies.