The digital epidemiology of Staphylococcus aureus

Digital epidemiology encompasses an emerging set of analytic techniques and approaches to data collection. Data in these studies are almost always born digital -- they are not recorded or transcribed by hand -- and often the research involves online networks in one guise or another. While these methods are being utilized increasingly, studies combining both digital network data and microbiological data on the spread of hospital associated pathogens have, so far as I know, been missing. 

Obadia et al have published an exemplary study doing just this for the case of MRSA and MSSA in a long term care center. Many researchers have in the past adopted a very reasonable and plausible hypothesis regarding the spread of staph in hospitals: namely, that it depends to a large extent upon person to person contact. If that's true, then obviously the ways in which patients and healthcare workers (HCWs) interact with one another, i.e., the patient-patient and patient-HCW contact networks, must be important for understanding spread. To my knowledge, until this study, nobody has really documented this with clarity at the individual level.

Obadia et al have illustrated this relationship between staph infection and contact network structure quite clearly by utilizing wireless proximity sensing and spa typing. They demonstrate how to employ digital technology to measure who interacts with whom, how frequently, and for how long, over long periods of time, and how to combine that data with microbiological surveillance in order to observe how transmission depends on the web of contacts in a facility. The authors found that close proximity interaction (CPI) paths existed between those colonized with like staph strains, and that those path lengths were significantly shorter than paths between random pairs in the study population. This is in agreement with what is expected from the transmission hypothesis. Their study also highlighted the importance of HCWs as links in the chain of contacts between infected patients.

One important implication of this work is that it might be possible to prevent infections by managing and monitoring close contact paths between patients and patients and between HCWs and patients. The approach may also be useful for developing targeted surveillance strategies that can detect spread and break the contact pathways most likely to result in further spread. I recommend reading the paper, and also the excellent comments regarding it by Eli Perencevich at the Controversies in Hospital Infection Prevention blog.

Overall, I think this study is a great illustration of the power of digital epidemiology methods for gathering detailed data in order to understand how disease is spread in the real -- as opposed to the simplified, theoretical -- world. We need more like it to inform both our thinking about hospital associated infections and analytic models of such pathogens.

(image source: CDC)

The calculus of online credibility

It's been estimated that roughly one quarter of the global population will soon be using smartphones. Recently, Nathaniel Barr et al have studied how the instant and ubiquitous access to information from smartphone use is impacting our propensity for critical thinking. The paper's abstract captures the issue:

With the advent of Smartphone technology, access to the Internet and its associated knowledge base is at one’s fingertips. What consequences does this have for human cognition? We frame Smartphone use as an instantiation of the extended mind—the notion that our cognition goes beyond our brains—and in so doing, characterize a modern form of cognitive miserliness. Specifically, that people typically forego effortful analytic thinking in lieu of fast and easy intuition suggests that individuals may allow their Smartphones to do their thinking for them. Our account predicts that individuals who are relatively less willing and/or able to engage effortful reasoning processes may compensate by relying on the Internet through their Smartphones. . . . These findings demonstrate that people may offload thinking to technology, which in turn demands that psychological science understand the meshing of mind and media to adequately characterize human experience and cognition in the modern era.

Tania Lombrozo, writing for NPR, put it more succinctly:

We all know a little knowledge can be a dangerous thing. Research increasingly supports a related proposition — that easy knowledge can be a dangerous thing.

I don't want to go into the strengths and weaknesses of the study, or it's ability to assess causality. Researchers will no doubt address these important issues in time, and Lombrozo discusses them nicely in her essay. However, it's important to contemplate some of the implications of the study.

One implication is that, as the Internet and mobile technology have changed the way we acquire information, they have also changed the way in which we assess its credibility. We've all seen people read claims and discussions from different online media and rapidly accept them as true. Sometimes the information they glean is true -- online communities of people possessing similar interests and expertise are often rich sources of specialized information -- whereas other times online discourse is not so authoritative. Regardless, acceptance of what surfers read is often rapid. If people increasingly rely on digital information and forgo complex, analytic thinking -- the "cognitive miserliness" that Barr et al describe -- perhaps it's because they trust what they're reading.

If true, what are the implications for public health? Insofar as health behavior is influenced through online information gathering, we must understand how people determine trust and credibility of online information. Professional achievement in terms of academic degrees, certifications, or job titles of those publishing information online may be important, but also important are a source's online profile in terms of site appearance and ease of navigation, number of followers, and number of page views. In fact, the latter may be more important than the former.

If it's true that we are increasingly putting our brains in our pockets and avoiding critical thinking, as Barr et al suggest, then it's important to understand the calculus of credibility in cyberspace. If people find Facebook, Reddit threads, and Fox News more credible than the CDC or their own doctor -- rightly or wrongly -- we had better understand why and engage it as a tool.

(image source: David Hartley)