The dog that originally infected Rusty was still busy, moving through the neighborhood. The next infected dog belonged to a young woman down the street named Casey, who called her dog in after the infection.
"Sammy, come in here boy!" Casey says, her long red hair falls to her shoulders, she's wearing a robe to cover her already naked body as her dog Sammy comes running in. Sammy pokes his nos between her legs, lightly licking her pussy. "Ooh, someone's getting frisky," she says, and pushes his snout away. "Sammy, just be patient," she says, and undoes her robe, letting it fall away, revealing her naked body and C-cup breasts, Sammy wags his tail happily, anticipating what's to come.
Casey sits down, and spreads her legs, Sammy pushes his snout in, and begins licking her pussy. Not knowing about the infection, Casey is too distracted to notice as her pussy changes to that of a dog, and fur begins to spread up her body. Almost instictively, she moves over onto all fours, and her golden retriever mounts her, plunging his cock into her changing pussy. With each thrust, Casey changes into a golden retriever, when his knot has finally deflated, she's fully a dog, and lets out a bark. She knew what she had to do, spread the virus and turn as many as possible into dogs.