23,054 research outputs found
Endemicity and prevalence of multipartite viruses under heterogeneous between-host transmission
Multipartite viruses replicate through a puzzling evolutionary strategy.
Their genome is segmented into two or more parts, and encapsidated in separate
particles that appear to propagate independently. Completing the replication
cycle, however, requires the full genome, so that a systemic infection of a
host requires the concurrent presence of several particles. This represents an
apparent evolutionary drawback of multipartitism, while its advantages remain
unclear. A transition from monopartite to multipartite viral forms has been
described in vitro under conditions of high multiplicity of infection,
suggesting that cooperation between defective mutants is a plausible
evolutionary pathway towards multipartitism. However, it is unknown how the
putative advantages that multipartitism might enjoy at the microscopic level
affect its epidemiology, or if an explicit advantange is needed to explain its
ecological persistence. To disentangle which mechanisms might contribute to the
rise and fixation of multipartitism, we investigate the interaction between
viral spreading dynamics and host population structure. We set up a
compartmental model of the spread of a virus in its different forms and explore
its epidemiology using both analytical and numerical techniques. We uncover
that the impact of host contact structure on spreading dynamics entails a rich
phenomenology of ecological relationships that includes cooperation,
competition, and commensality. We find that multipartitism might rise to
fixation even in the absence of explicit microscopic advantages. Multipartitism
allows the virus to colonize environments that could not be invaded by the
monopartite form, facilitated by homogeneous contacts among hosts. We
conjecture that these features might have led to an increase in the diversity
and prevalence of multipartite viral forms concomitantly with the expansion of
agricultural practices.Comment: 27 pages, 4 figures, 1 tabl
Recoverable prevalence in growing scale-free networks and the effective immunization
We study the persistent recoverable prevalence and the extinction of computer
viruses via e-mails on a growing scale-free network with new users, which
structure is estimated form real data. The typical phenomenon is simulated in a
realistic model with the probabilistic execution and detection of viruses.
Moreover, the conditions of extinction by random and targeted immunizations for
hubs are derived through bifurcation analysis for simpler models by using a
mean-field approximation without the connectivity correlations. We can
qualitatively understand the mechanisms of the spread in linearly growing
scale-free networks.Comment: 9 pages, 9 figures, 1 table. Update version after helpful referee
comment
- …