Emerging infectious diseases (EIDs) are a significant burden on global economies and public health1,2,3. Their emergence is thought to be driven largely by socio-economic, environmental and ecological factors1,2,3,4,5,6,7,8,9, but no comparative study has explicitly analysed these linkages to understand global temporal and spatial patterns of EIDs. Here we analyse a database of 335 EID ‘events’ (origins of EIDs) between 1940 and 2004, and demonstrate non-random global patterns. EID events have risen significantly over time after controlling for reporting bias, with their peak incidence (in the 1980s) concomitant with the HIV pandemic. EID events are dominated by zoonoses (60.3% of EIDs): the majority of these (71.8%) originate in wildlife (for example, severe acute respiratory virus, Ebola virus), and are increasing significantly over time. We find that 54.3% of EID events are caused by bacteria or rickettsia, reflecting a large number of drug-resistant microbes in our database. Our results confirm that EID origins are significantly correlated with socio-economic, environmental and ecological factors, and provide a basis for identifying regions where new EIDs are most likely to originate (emerging disease ‘hotspots’). They also reveal a substantial risk of wildlife zoonotic and vector-borne EIDs originating at lower latitudes where reporting effort is low. We conclude that global resources to counter disease emergence are poorly allocated, with the majority of the scientific and surveillance effort focused on countries from where the next important EID is least likely to originate.
We thank the following for discussion, assistance and comments: K. A. Alexander, T. Blackburn, S. Cleaveland, I. R. Cooke, A. A. Cunningham, J. Davies, A. P. Dobson, P. J. Hudson, A. M. Kilpatrick, J. R. C. Pulliam, J. M. Rowcliffe, W. Sechrest, L. Seirup and M. E. J. Woolhouse, and in particular V. Mara and N. J. B. Isaac for analytical support. This project was supported by NSF (Human and Social Dynamics; Ecology), NIH/NSF (Ecology of Infectious Diseases), NIH (John E. Fogarty International Center), Eppley Foundation, The New York Community Trust, V. Kann Rasmussen Foundation and a Columbia University Earth Institute fellowship (K.E.J.).
Author Contributions P.D. conceived and directed the study and co-wrote the paper with K.E.J.; K.E.J. coordinated and conducted the analyses with M.A.L., A.S., N.G.P. and D.B.; N.G.P. compiled the EID event database; and J.L.G provided the mammal distribution data. All authors were involved in the design of the study, the interpretation of the results and commented on the manuscript.
The file contains the following: Supplementary Data; Supplementary Figures S1-S3; and Supplementary Tables S1-S3. Supplementary Data contains the EID Event Database (Table S1) along with the source details and a comparison to other variable definitions (Table S2). Figure S1 shows the Latitudinal gradient in EID events. Figure S2 shows the Global richness maps of EID events from 1940-2004 split by category and Figure S3 shows the Spatial reporting bias in EID events. Table S3 gives the results of the Socio-economic, environmental and ecological correlates of EID events for 10 random spatial draws.