Who knew that so many commuters on trains and buses in England carry fecal bacteria on their hands? Val Curtis, medical anthropologist and public health expert, teamed up with five other researchers to assess the presence or absence of fecal bacteria on the hands of over 400 people in five UK cities. Dr. Curtis is a leading proponent of hand washing with soap in developing countries as a powerful mechanism to reduce infant and child mortality.
The findings from the UK study are gripping (so gripping in fact that you may never want to shake anyone’s hand again).
Overall, 28 percent of the 404 people sampled had bacteria of fecal origin on their hands. The authors break that figure down by region and gender. The further north you go, the higher are the percentages of men (not women) with fecal bacteria on their hands. In Newcastle, the most northerly city in the study, nearly 60 percent of the men had fecal bacteria on their hands compared to 5-15 percent in London and Cardiff. The percentage for women in all five cities had a more narrow range, between only 20-30 percent.
Beside region and gender, mode of transportation also revealed differences. Men on buses are more likely to have fecal bacteria on their hands than men who ride trains. And professionals are more likely to have fecal bacteria on their hands than others.
These findings and some complicating factors cry out for further research. First, no difference appeared between people who reported having washed or not washed their hands that morning. Second, the bacteria that were isolated are found in other contexts such as working with food or animals. Third, the sample sizes, especially of men in London (only six) are small, and London is the only truly “southern” city in the study. Fourth, the study assessed only the absence or presence of fecal bacteria and not degrees of difference in the latter.
Blogger’s note: I eagerly await findings from larger follow-up studies that take into account age and ethnicity, and that sample people in more cities. Then on to Scotland and Ireland…and maybe even to the Washington DC metro system that I use to get to work.
SOURCE: G. Judah, P. Donachie, E. Cobb, W. Schmidt, M. Holland, and V. Curtis, Dirty Hands: Bacteria of Faecal Origin on Commuters’ Hands. Epidemiological Infections, 2009.
Image: “Brazil fans on London undergound,” from flickr user markhillary, licensed with Creative Commons.