Ongoing worldwide homogenization of human pathogens

1 Background – Infectious diseases are a major burden on human population, especially in lowand 2 middle-income countries. The increase in the rate of emergence of infectious outbreaks necessitates 3 a better understanding of the worldwide distribution of diseases through space and time. 4 Methods – We analyze 100 years of records of diseases occurrence worldwide. We use a graph-theoretical 5 approach to characterize the worldwide structure of human infectious diseases, and its dynamics over 6 the Twentieth Century. 7 Findings – Since the 1960s, there is a clear homogenizing of human pathogens worldwide, with most 8 diseases expanding their geographical area. The occurrence network of human pathogens becomes 9 markedly more connected, and less modular. 10 Interpretation – Human infectious diseases are steadily expanding their ranges since the 1960s, and 11 disease occurrence has become more homogenized at a global scale. Our findings emphasize the 12 need for international collaboration in designing policies for the prevention of outbreaks. 13 Funding – T.P. is funded by a FRQNT-PBEE post-doctoral fellowship, and through a Marsden grant 14 from the Royal Academy of Sciences of New-Zealand. Funders had no input in any part of the study. 15 2 . CC-BY 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/009977 doi: bioRxiv preprint first posted online Oct. 3, 2014;