In a study that may make you want to go wash your hands, Weill Cornell Medical College's Christopher Mason and his colleagues report on the microbial species living in the New York City subway system as well as in some city parks and the Gowanus Canal, as GenomeWeb reports.
Like the city itself, Mason and his team found the subway microbiome to be diverse. They report in Cell Systems that nearly half of the DNA they collected didn't correspond to any known organisms, and those they could identify belonged to some 1,688 taxa, including bacterial, viral, archaeal, and eukaryotic groups. Most, though, were linked to harmless skin-related genera like Acinetobacter.
However, the researchers did pick up some evidence of pathogens like Bacillus anthracis and Yersinia pestis lurking in the city, but they noted that as there are no reported cases that their sample likely reflects a normal city microbiome.
"People don't look at a subway pole and think, 'It's teeming with life,'" Mason tells the New York Times. "After this study, they may. But I want them to think of it the same way you'd look at a rain forest, and be almost in awe and wonder, effectively, that there are all these species present — and that you've been healthy all along."
From the human DNA left on subway poles, turnstiles, and elsewhere, the researchers were also able to predict the ancestries of riders, predictions they note are largely in line with US Census reports.
The researchers also tell the Times that cataloguing the microbiome now could serve as a baseline for future disease or bioterrorism studies.
City officials, the Times notes, "did not sound grateful for the examination." The Metropolitan Transportation Authority's Kevin Ortiz emphasizes that the study found microbes at levels that don't threaten human life or health, while the health department says the study was "deeply flawed" and misleading.
Mason counters that leaving out that they'd found anthrax and plague fragments would've been "irresponsible" science.
"Our findings indicate a normal, healthy microbiome, and we welcome others to review the publicly available data and run the same analysis," he adds.