This is from today's Wall Street Journal about an 18 month study of gathering information on the germs throughout the NYC subway system.
A swab was rubbed back and forth on a hand rail of a number 6 train to collect any DNA on the hand rail, and to determine what type of bacteria what was found may be. In 18 months of scouring the entire system germs that can cause bubonic plague uptown, meningitis in midtown, stomach trouble in the financial district and antibiotic-resistant infections throughout the boroughs were found. This could be a mirror of the people themselves who ride the subway system.
DNA was gathered from turnstiles, ticket kiosks, railings and benches in a transit system shared by 5.5 million riders every day. More than 10 billion fragments of biochemical code—and sorted it by supercomputer were found at 446 subway stations. 15,152 types of life-forms. were found to be in the subway system.
For the entire Wall Street Journal article including an interactive map many Manhattan subway stations click here.