The design of protocols to suppress the propagation of viral infections is an
enduring enterprise, especially hindered by limited knowledge of the mechanisms
through which extinction of infection propagation comes about. We here report
on a mechanism causing extinction of a propagating infection due to
intraspecific competition to infect susceptible hosts. Beneficial mutations
allow the pathogen to increase the production of progeny, while the host cell
is allowed to develop defenses against infection. When the number of
susceptible cells is unlimited, a feedback runaway co-evolution between host
resistance and progeny production occurs. However, physical space limits the
advantage that the virus can obtain from increasing offspring numbers, thus
infection clearance may result from an increase in host defenses beyond a
finite threshold. Our results might be relevant to better understand
propagation of viral infections in tissues with mobility constraints, and the
implications that environments with different geometrical properties might have
in devising control strategies.Comment: 4 pages, 3 figures Accepted for publication in Physical Review
Letter