Walker is technically right about anthrax having no cure, there is nothing that can cure it 100% of the time. However natural un-enhanced anthrax, like the kind he harvested from contaminated animal hides, is actually very treatable with broad spectrum antibiotics like Ciprofloxacin.
At the end of the episode the song "Stand By Me" remixed by Ki: Theory, was playing. This song also played in the TV show The Following (2013), which also had Sam Underwood in it.
This episode marks the last time we see the Abigail, which we last saw in the sixth episode of Season 2, Sicut Cervus (2016).
Via his conversation with the stranded Russian cosmonaut, Strand establishes that the zombie apocalypse is worldwide and not just confined to the US.