Shows backward bifurcation structure when reinfection path <i>A</i> is excluded.

<p>Parameters used are the same as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0194256#pone.0194256.g010" target="_blank">Fig 10</a> except <i>θ</i> = 7.5 > <i>θ</i>_<i>c</i> = 5. The solid blue line represent stable equilibrium while the dotted red line represent unstable equilibrium. Semi-logarithmic scales are used to aid visualisation.