Proportion of Hosts Surviving over Time Depending on Treatment

<p>Solid, dashed, and dotted lines represent infected, exposed but uninfected, and unexposed control daphniids, respectively. Survival analysis showed a highly significant difference in survival between the infected as compared to unexposed control hosts ( <i>p</i> < 0.001), while there was no difference between the two groups of uninfected daphniids ( <i>p</i> = 0.719). The + symbols at the two curves representing uninfected daphniids indicate points where censoring was performed. For more details about the statistics, see <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0040197#s3" target="_blank">Materials and Methods</a>. Mean age at castration is the mean age at which infected animals became castrated. Age at castration is defined as the first day after a host's last reproduction. All infected daphniids had become castrated at an age of 19 d (17 d after infection + 2 d).