# wombat urls ß
Competition of fluorescently marked temperate phage (λCFP and λYFP - blue and green) during invasion into regions of uninfected cells (black areas).
The circular epidemic front segregates into single-virus sectors (blue and green sectors), even though the two marked phages have the same genetic background and the epidemic is inoculated as a dot of a homogeneous mixture of the strains. Stochastic sampling in the epidemic wave and exclusion of superinfection of the competing phage might be at the origin of this effect. This picture illustrates the intricate effects that spatial structure and vertical transmission introduce into the spread of epidemics. Berngruber et al.
Image Credit: Thomas Berngruber