Listeria is not passed from goat to goat. It is caused by them eating something (usually fermented or molded) that contains the Listeria bacteria. There are other diseases like this as well such as Clostridiums B, C, & D, Tetanus, Anthrax, Blackleg, etc.
I would have no problem with bring him to my place as long as he was healthy at that time.
I spray feet with vinegar/bleach after unloading the animal and before putting him in my pen. That way normal barnyard germs don't get tracked in.
Listeria is a group consisting of 6 different organisms.
The common Listeria Ivanovii we see in goats affects the brain and nerve function causing the symptoms of staggering, circling, can progress to a stroke, etc. It is not contagious goat to goat.
The Listeria Monocytogenes that causes an outbreak is a different bacteria in the same family. It is the one that is passed in milk, feces, and indeed sperm. These outbreaks cause the Public Health Authority to shut your whole operation down and pull your licenses. These outbreaks are so rare as to be nonexistent among the goat world.
The other thing about Listeria is that, like Staph, it is everywhere in the environment. Chances are one or two of your human family carries it, a goat or two, it's carried by rodents, insects, wild animals of all types, and even some pond snails and such. So really it is impossible to quarantine against it. The only real defense is keeping the immune system strong by raising healthy animals.