What can I do about protecting myself from a contagious disease at work?

Keep it simple. Wash your hands often for starters. Cover your mouth with the inside of your arm/elbow or hand (clean or sanitize afterward). Wipe your desk and phone down with clorox at the start of the day. Eat right. Exercise. Get plenty of rest. Hydrate well. Share the above with your co-workers.
Hand washing. Good hand washing, decontamination of your telephone, computer key board and door knobs are the best things you can do.