Buggy Transportation

All the bugs in the metro, tube, subway, from NYC to Asia

By Jesica Levingston Mac leod, PhD

The New York City (NYC) subway is use for more than 5 million passengers per day. Passengers being humans, pets, bacteria, parasites, viruses and other unknown creatures. Consequently infectious diseases, like influenza can be easily transmitted in this transportation method. Other dangerous circumstances are the black carbon and particle matter concentrations, which In Manhattan are considerably higher than in the urban street level. If you have just ridden the subway, I recommend that you check you washed your hands before continue reading…because, literately, this article is about shit!

Last Month a great research team from Cornell published the studies on microorganisms from 466 subway stations where they found 76 known pathogens (aka “bad” bacteria), and, more interestingly, they found a lot of unknown organisms. This means that almost half of all DNA present on the subway’s surfaces matches no known organism. As they could identified some of the microorganisms, they described that these bacteria were originated in some metropolitan citizen food, pet, workplace… you can actually check which kind of bacteria was found in your favorite/closest subway station… just to be sure what to tell to your doctor next time that you have some infection….

During a year and a half, Dr. Mason, the leader of the group, took samples from materials like the metal handrails in order to collect DNA for the big data genetic metropolitan profile project, aka the Pathomap project. From the 15,152 types of life-forms, almost half of the DNA belonged to bacteria—most of them harmless; However, the scientists said the levels of bacteria they detected pose no public-health problem. The most prevalent bacterial species was Pseudomonas stutzeri, with enrichment in lower Manhattan (aka finance species ;)), followed by strains from Enterobacter and Stenotrophomonas. Notably, all of the most consistently abundant viruses (only 0.03%) were bacteriophages, which were detected concomitant with their bacterial hosts.

Other study done in 2013 in Norway, found that the airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly human passengers) were the major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. The peaks are at 8 am and 5 pm, following the rush hours.

Other great discovery was that the human allele frequencies in the subway mirrored US Census data. Within the neighborhoods they found African American and Yoruban alleles correlation for a mostly black area in Brooklyn, Hispanic/Amerindian alleles in the Bronx and they observed that Midtown Manhattan showed an increase in British, Tuscan, and European alleles.

In this globalized world, you won’t be surprised that in the London’s Tube a group of journalist and researchers found more than 3 million bacteria. These data suggested that the average train or bus seat could have more than 70 types of bacteria, plus cold and flu viruses. The North-South Victoria line was the only one that passed the hygiene test.

In a study at the Hong Kong subways system, researchers analyzed aerosol samples in order to find the taxonomic diversity of the “under” microbes. Each bacterial community within a line was dependent on architectural characteristics, nearby outdoor micro biomes, and distance to other lines, and were influenced by temperature and relative humidity.

Altogether these results sound really scary, but I hope that the reader won’t react panicking, but just being aware of the bad pathogens around him/her and carry a hand sanitizer/mask/cleaning aerosol/wipes or just wash your hands with soap! Actually, health officials from the FDA, believe washing hands with soap and water is the best method to get rid of germs.