Scientists have found traces of anthrax and bubonic plague in the DNA testing of subways in New York City, but they suggest that this is nothing to worry about.

Weill Cornell Medical College in New York, joined with investigators from five other New York City medical centres and spent 17 months collecting DNA from turnstiles, benches, hand railings, bins and kiosks in all of New York City’s open subway stations. Nylon swabs were also used to collect samples from the train interiors including seats, doors, poles and handrails.

Using a purpose-built mobile app, the researchers were able to time stamp each sample, tag it using GPS and log the data in real time of more than 4,200 DNA samples collected, 1,457 of which have been sequenced and analysed so far. The majority of the DNA collected contained 48.3% that did not match any known organisms. The researchers say this “underscores the vast wealth of unknown species that are ubiquitous (seeming to be everywhere) in urban areas.”

No cause for panic

Dr Christopher E. Mason, the study’s senior investigator, suggests that these unexplained microbes are unlikely to cause any harm. He said: “Our data show evidence that most bacteria in these densely populated, highly trafficked transit areas are neutral to human health and much of it is commonly found on the skin or in the gastrointestinal tract. These bacteria may even be helpful, since they can out-compete any dangerous bacteria.”
Of the organisms that were identified 46.9% were bacteria and only 0.32% were viruses, but as some seasonal viruses are RNA – rather than DNA viruses, they would not have shown up in this study.

Most of the subway bacteria (57%) have never been linked with disease in humans. However, 31% of the bacteria were considered to be ‘opportunistic bacteria’ which could cause illness in people who have a low immune system and the remaining 12% were considered to ‘have some evidence of pathogenicity.’

Plague and Anthrax

Among all of the samples collected, two contained DNA fragments of anthrax and a plasmid associated with bubonic plague. Luckily, for the peace of mind of subway users worldwide, they have been found at very low levels and there was no indication these microbes were alive.

Dr Mason said: “Despite finding traces of pathogenic microbes, their presence isn’t substantial enough to pose a threat to human health. 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.”
Dr Mason considers the findings of the study to be generally reassuring and says there is no need for alarm, with precautions such as avoiding subways or wearing protective gloves not being necessary.

He added: “[The study] also establishes the first baseline data for an entire city, revealing that low levels of pathogens are typical of this environment. While this is expected in rural environments, and also present in livestock, we’ve never seen these levels before in cities. We can now monitor for changes and potential threats to this balanced microbial ecosystem.”

DNA tests can come in handy for a whole host of scenarios it seems, they can give peace of mind even in a situation that initially seems worrying. AlphaBiolabs provide DNA and Drugs & Alcohol testing to give you the answers you need and can put your mind at ease.