Right, and I don’t like those versions. Viruses exist to perform their function, though. Nothing more, nothing less. They are simple microorganisms. Even if Zeta did indeed affect the cortex area relative to breathing, it still wouldn’t make the zombie do the action, as it serves literally no purpose to the pathogen’s goal: spread. This is why zombies can’t, again, produce waste. Its why they can’t talk, read, write, think critically, or other things: because they don’t need to. Consume flesh, spread the infection; that’s the virus would be concerned with. No reflexes would take place, either; its the virus that controls everything. The zombie is a zombie because of Zeta, and only because.
In short, the virus only preserves what is relative to its function.
It would be different if the virus didn’t kill then reanimate and instead just affected people like in 28 Days Later, but, in ZE, they are unfortunately not that.