The team of scientists combined big data analytics, microbiology and urban research to complete the experiment. Joe Vitale/The Fordham Ram
By Joe Vitale
The New York City subway carries more than 5 million riders on any given day. It is crowded, it is dirty and, regardless of how many passengers are in any given subway car, teeming with microbial life.
Scientists have known this for some time, but a recent scientific study of the subway’s microbial system organized, synthesized and even mapped the findings.
The team of scientists, led by Dr. Christopher Mason of Weill Cornell Medical College, combine big data analytics, microbiology and urban research to conduct the study.
Published in Cell Systems, the study shows that it is not only possible, but useful to develop a “pathogen map” — nicknamed a “PathoMap” — of a city with a crowded transportation system.
The majority of the 637 known bacterial, viral, fungal and animal species detected were non-pathogenic and represent normal bacteria commonly found on humans, though half of the sequences of DNA they collected could not be identified.
Still, nearly 12 percent of the bacterial species sampled showed an association with disease.
The group of researchers, which ranged from graduate students to volunteers, sampled thousands of surfaces in the system, including turnstiles, trashcans, wooden and metal benches, stairway hand railings and kiosks. They also collected samples from the inside of trains. In all, they covered every open subway station in 24 subway lines in five boroughs.
The study was entering a largely unexplored field, he said. But its contribution was sizable, offering an analysis of more than 10 billion fragments of biochemical code.
The Bronx, researchers found, is the most diverse borough in terms of microbial species. Brooklyn was second, followed by Manhattan, Queens then Staten Island.
In the nearest subway station to campus, the Fordham Road Station, which serves as a hub for the B and D trains, researchers identified 49 unique types of bacteria.
The researchers, after swabbing Metrocard Vending Machines and a bench, found 49 unique bacteria at this location including species associated with urinary tract infections, Italian cheese, sepsis, toxic clean-up, among other species, according to a Wall Street Journal infographic. Sergios-Orestis Kolokotronis, Ph.D., assistant professor in the Department of Biological Sciences at Fordham, was among the study’s co-authors.
“This is part of a large effort beyond scanning the city for pathogens – with obvious implications for public health and biodefense – that extends to establishing a baseline understanding of life as it evolves and adapts to highly urbanized environments,” Kolokotronis said.
He was among several New York City-based professors, including those from New York University and the State University of New York, Downstate.
The study was not just conducted to gross subway riders out. The findings and subsequent sampling, the report found, could be used for disease surveillance, bioterrorism threat mitigation and health management for the city.
The study was widely covered in city newspapers and many city Officials commented on the findings.
The city’s Health Department called the study “deeply flawed” and misleading.
“As the study clearly indicates, microbes were found at levels that pose absolutely no danger to human life and health,” Kevin Ortiz, a spokesman for the Metropolitan Transportation Authority, told the New York Times in an email.
Scientists who conducted the study say there is no reason to be worried.
“Despite finding traces of pathogenic microbes, their presence isn’t substantial enough to pose a threat to human health,” Dr. Mason said in a press release regarding the study. “The presence of these microbes and the lack of reported medical cases is truly a testament to our body’s immune system, and our innate ability to continuously adapt to our environment.”
Correction: An earlier version of this article reported that a spokesperson for the Metropolitan Transportation Authority called the study “‘deeply flaw’ and misleading.” It was the Health Department, not a spokesperson for the MTA, that said this. A spokesperson for the MTA, Kevin Ortiz, said: “As the study clearly indicates, microbes were found at levels that pose absolutely no danger to human life and health.”