Figure 1. Example inference of incident infection of growing clusters characterized by internal node post-dating the identification of the high-priority cluster.

Tip labels represent date of diagnosis. Tip dates colored in blue were identified as cases in the high-priority cluster as of identification in 2012. In this example tree, we can infer an incident infection post-2012 (dark green circle); however, we cannot determine which, if either descendant is the source or recipient partner with incident HIV. Further, we can infer an undiagnosed infection as of 2012 (light green circle).