This isn't 100% accurate (Its about 95%)
A husk can also be a villager that has been turned into a zombie. There are several varieties of this sort of infection scenario. I think we have 3 on the server because of the MCA mod.
You have to pay attention to the zombie skin, if it looks like any other zombie but with different colors you are safe to kill it. If it looks like a really nasty looking, angry villager, then don't kill it, as you can cure it.
You need a splash potion of weakness, and a golden apple. You hit the infected with a splash potion, and then trade it a golden apple, and it will be cured. I will warn you though, you don't get anything for curing them. They just say thank you and walk away. So you can kill them, but the village guards might take offense to it.
What I do here is if I am in a village I cure them, if I am just outside a village and no guards are near, I kill them