This short story concerns a parasitic fungus, very similar to the infamous Ophiocordyceps unilateralis in ants. In this story, it was used as a bio-weapon, and has taken over large swaths of America. It is fatal once contracted, and late-stage infected hosts will climb poles or trees and "bloom", spreading more fatal spores.
Setting: It is set in a future post-apocalyptic America, following several nasty bio-terror wars. The USA has collapsed and reformed as the Catholic States of America (CSA) and some splinter groups.
The protagonist, a male veteran from the war. He lives alone in the forest, and objects to the iron-fisted CSA.
A beast-woman, genetically modified to serve as a bloodhound during the war.
The CSA, an oppressive fundie government that is the only surviving authority around.
Plot: The protagonist is traveling to his home when he is exposed to a "bloomer". Local emergency crews come to sanitize the area. Protagonist is later diagnosed with the fungus. He is roughed up by CSA goonies for dissent. He is comforted by his companion, the beast-woman. She offers to mercy-kill him to prevent the inevitable end. He tells her to leave their area before things get worse. He succumbs to the parasite and "blooms" himself, furthering the cycle.
This was in a sci-fi short story anthology from the....70's? 80's?. I have searched and searched. Any help from fellow dusty tome readers would be much appreciated.
Similar to this question Sci-fi/horror short story about a disease that took over people’s minds and made their heads explode, but the story I'm looking for is none of the answers there.