How the dogs...Became zombie dogs in Penumbra overture -----=POSSIBLE SPOILERS------=

[Sexbad]

Spoiler below!

I'm almost certain that the dogs are infected by the Tuurngait. It was said somewhere it infects any living organism, so dogs certainly are an organism.

On a slightly related note, the dogs and possibly rock worms being connected to the hive mind might be a reasonable explanation for how Red could see where Phillip was all the time. Even if the dogs didn't pick up on the senses they had that he was near them, sneaking by, or breaking their face open, the hive could know.