Globalization considerably increased probability of pandemics. Consequently, many researchers investigated what are the dynamics of rapidly spreading diseases. However, new study carried out by Swiss sociologists suggests that one important mechanism of disease dissemination was overlooked.
“Here we study the dynamics of an epidemic when the recovery of sick individuals depends on the availability of healing resources that are generated by the healthy population. We find that epidemics spiral out of control into explosive pandemics if the cost of recovery is above a critical cost,” they say.
Dangers created by global epidemics are clear. Spanish influenza killed 50 million people one century ago. And past world was less connected than the present one. Over 3 billion people travel by plane each year. Large number of interactions creates conditions for new dangerous viruses will be transmitted very rapidly. These challenges are well known and considerable efforts were invested into understanding of the diffusion of viruses.
“Important progress in understanding epidemic spreading has been made using mathematical models that capture the underlying processes and their dependence on infection and recovery rates. These studies have focused mainly on the interplay between the dynamics and the structure of interactions, on identifying the main spreaders,” the scientists note.
However, most of the contemporary mathematical models assume that disease outbreaks can be solved without treatment or that treatment capacities are unlimited. However, Lucas Böttcher and his colleagues at ETH Zürich thought that this factor can play a decisive role as well.
“A large enough healthy and productive population is crucial to enable the recovery of those that become ill: Healthy individuals are both the human resources needed to provide health services and pharmaceuticals, and contributors to the healthcare budget through taxes and insurance premiums,” the scholars explain.
Expanding epidemics reduce resources needed for its treatment and consequently reinforce itself. Computer simulations showed that situation becomes uncontrollable when recovery cost becomes critical. Moreover, this change is very fast and does not depend on social networks structuring human interaction.
“This discontinuity indicates the importance of carefully monitoring the situation in order to avoid a sudden and uncontrollable transition into the pandemic regime,” the sociologists emphasize.
Article: Böttcher, Lucas and Woolley-Meza, Olivia and Araujo, Nuno A.M. and Herrmann, Hans J. and Helbing, Dirk, Disease-Induced Resource Constraints Can Trigger Explosive Pandemics (August 6, 2014). Available at SSRN, source link.