Synopsis: Hidden epidemic

New ways to describe the spread of “persistent” diseases, which can lie dormant in the population for years, are emerging from statistical physics.

As computational resources modernize, physicists have become increasingly interested in understanding the dynamics of disease spread. The problem is essentially one of statistical physics, where the theory of phase transitions and critical phenomena and the tools of numerical simulations enable physicists to predict how epidemic outbreaks will evolve in time [1].

Most recent progress has considered diseases that die out quickly, but when persistent infections occur in a population, individuals may be infected but not infectious (i.e., “latently” infected) for long periods of time—even a lifetime. From a technical point of view, this seemingly minor aspect implies the system is open, since newborns enter the dynamics and some individuals die for causes not directly related to the disease. Now, in a paper appearing in Physical Review E, Joaquín Sanz, L. Mario Floría Peralta, and Yamir Moreno Vega at the Universidad de Zaragoza, Spain, report on the threshold for an epidemic to occur for persistent diseases. In particular, they consider one of the most threatening cases, tuberculosis.

Using the tools of network theory to describe the way individuals interact and infect one another, Sanz et al. show that the epidemic threshold depends on the distribution in the connectivity of the network nodes; namely, the ratio between the mean and standard deviation of this distribution. Although this result is similar to what occurs in diseases without latent periods, the techniques and ideas Sanz et al. have introduced represent an important step towards the modeling of persistent infections that will be useful in more general contexts. – Alex Arenas

[1] I. B. Schwartz and L. B. Shaw, Physics 3, 17 (2010).


Features

More Features »

Announcements

More Announcements »

Subject Areas

Biological PhysicsInterdisciplinary Physics

Previous Synopsis

Quantum Information

Flights of fancy

Read More »

Next Synopsis

Related Articles

Focus: Drops Falling in Clouds Make More Drops
Fluid Dynamics

Focus: Drops Falling in Clouds Make More Drops

Experiments with a simplified version of the atmosphere show that falling drops seed many smaller droplets in their wake. Read More »

Synopsis: Teaching Fish How to Swim
Fluid Dynamics

Synopsis: Teaching Fish How to Swim

A new model of swimming fish and cetaceans pinpoints the parameters that matter most for efficient motion. Read More »

Focus: Bacteria Form Waveguides
Biological Physics

Focus: Bacteria Form Waveguides

A laser beam sent through a suspension of marine bacteria pulls the organisms into the beam, which focuses the light. Read More »

More Articles