The accelerated infectious disease risk in the Anthropocene: more outbreaks and wider global spread

Serge Morand; Bruno Andreas Walther

Similarly, the presence of airports and railway stations significantly advanced the arrival of influenza during the 2009 pandemic in China (Cai et al., 2019) . Global connectivity due to air traffic allows an outbreak to rapidly spread across several national and continental borders within a short period of time. For example, the Ebola virus outbreak was brought into the continental USA onboard a commercial flight from Liberia because the host was asymptomatic during the flight (CDC, 2014) . Sevilla (2018) reviewed and modelled how air travel can aid the global spread of Ebola, H1N1 influenza, SARS-CoV-1, and pneumonic plague. A systematic review of the effectiveness of travel reductions concluded that internal travel restrictions as well as international border restrictions both delay the spread of influenza epidemics (Mateus et al., 2014) . Therefore, given the staggering global increase in global mobility during the Anthropocene documented in Table 1 , the increase of the number of disease outbreaks, of diseases involved in these outbreaks, and of countries affected, as well as the decrease of modularity of these disease outbreaks make sense because the mobility of humans, other living beings, and goods (which can act as carriers or vectors) all facilitate the spread of disease and species (e.g., Smith and Guégan, 2010; Findlater and Bogoch, 2018; Sardain et al., 2019) .