(September 9th, 2014) Normally a measure for a researcher’s productivity and the impact of his published work, UK scientists found an alternative use for the Hirsch-index. With it, they determined the top 100 human and domestic animal pathogens in Europe.
Infectious pathogens are all around us but some of them are more harmful than others. For disease prioritisation, it is desirable to understand the risk associated with different pathogens. Standard measures include disease prevalence, mortality and morbidity rates, and associated costs. In a new paper, Marie McIntyre from the University of Liverpool and colleagues explore the use of the H-index, or Hirsch-index, which, traditionally, is a measure of a scientist’s productivity and the impact of his publications. But McIntyre et al. show that it can also be employed to indicate scientific interest in a disease and thus, be an alternative approach for disease prioritisation. To determine risk, the researchers combined the H-index with the number of publications on a particular disease. Luckily, McIntyre and co. had previously developed an extensive database with a comprehensive record of over 60 million publications associated with infectious diseases, the ENHanCEd Infectious Diseases (EID2) database.
Marie McIntyre tells Lab Times, “Classical risk assessment methods for infectious diseases/pathogens are very data-intensive and take a long time to complete as they need either (often unavailable/not known) information on lots of pathogens, or a minutiae of very specific information on one or a few pathogens.” In contrast the approach used here “doesn't need this kind of detail and so enables a simple quantitative risk assessment of infectious diseases/pathogens to be undertaken very quickly, and once set up the method can be repeatedly obtained to reflect changes in status, with the potential for automation of this process”. However, this was not a simple and quick study, as McIntyre says, “In total, the work has taken about five years, with the key problem being developing methods to undertake such a big risk assessment, using limited staff and resources - we're using very much 'big data' approaches.”
And what are Europe’s top pathogens? When it comes to those, preferably infecting us humans, the top five are: the well-known E. coli (with an H-index of 524), Human Immunodeficiency Virus 1 and 2, the Hepatitis C virus and Staphylococcus aureus. All of them cause diseases that are, unfortunately, familiar to most of us. McIntyre and colleagues also compiled a similar list for pathogens infecting domestic animals, including dogs, sheep, canaries and Alpaca. Interestingly, while the list of human pathogens contains three viruses, the top five domestic animal pathogens are all bacteria: E. coli (again!), S. aureus, Helicobacter pylori, Pseudomonas aeruginosa, Listeria monocytogenes. McIntyre explains “The work is unique because rather than selecting candidate pathogens/diseases to examine, we started with all known infectious pathogens, and then objectively and systematically decided, which occur in relevant hosts in Europe using a transparent process.”
McIntyre adds that “this work was part of the ENHanCE project (ERA NET Health and Climate in Europe), which examined the impact of climate change upon human health and well-being (via effects upon domestic animal pathogens) in Europe” and that the ongoing work in the group is preparation of a paper “describing the main results on climate” and “further work to develop the EID2 database”.
Image: E.coli by Mattosaurus