Dynamical correlations in the escape strategy of Influenza A virus

¹ Sapienza University of Rome, Physics Department - P.le A. Moro 5, 00185 Rome, Italy, EU
² Max Planck Institute for Mathematics in the Sciences - Inselstr. 22, 04103 Leipzig, Germany, EU
³ CNR-ISC - P.le A. Moro 5, 00185 Rome, Italy, EU
⁴ ISI Foundation - Via Alassio 11/c, 10126 Torino, Italy, EU

Received: 12 October 2012
Accepted: 6 March 2013

Abstract

The evolutionary dynamics of human Influenza A virus presents a challenging theoretical problem. An extremely high mutation rate allows the virus to escape, at each epidemic season, the host immune protection elicited by previous infections. At the same time, at each given epidemic season a single quasi-species, that is a set of closely related strains, is observed. A non-trivial relation between the genetic (i.e., at the sequence level) and the antigenic (i.e., related to the host immune response) distances can shed light into this puzzle. In this paper we introduce a model in which, in accordance with experimental observations, a simple interaction rule based on spatial correlations among point mutations dynamically defines an immunity space in the space of sequences. We investigate the static and dynamic structure of this space and we discuss how it affects the dynamics of the virus-host interaction. Interestingly we observe a staggered time structure in the virus evolution as in the real Influenza evolutionary dynamics.