I've also seen husks die during normal combat from "collision with an obstacle". A giant sea crab or somesuch was fighting a husked cat, the cat tried and failed for many pages to make a dent in the crab's armor (and lucky for the crab it didn't, first scratch would've passed the infection on); meanwhile the husk refused to die no matter how much the crab injured it. Eventually the crab hit the cat hard enough to send it flying into a wall a couple tiles away, it exploded in gore.
Interestingly, I got the announcement that the cat (a pet) had been killed the moment the husk "died", and the owner didn't get an unhappy thought about pet death until that moment, he didn't mind his cat being huskified. Looking through my dwarves I noticed friends and even spouses of recently husked dwarves have no unhappy thoughts either. The dwarves still consider husks very much "alive" (anyone watch the Walking Dead? Yeah, I'm thinking of the barn now).
By the way, in response to the earlier post about realistic infection vs. fantasy-magic reanimation: I think the point still stands that zombie reanimation is pure magic and should be treated as such, there's no reason to think destroying a reanimated corpse's head should work in DF ... but husks are actually a syndrome, in fact they share a lot in common with infection-style zombies (passing infection on the first scratch). I think it would make sense and be better gameplay if husks followed the "damage the brain = dead" rule of the zombie genre, even if the 'magically' reanimated undead don't. This would be quite different from the current system where you actually have to remove the head to get a kill, and all piercing/blunt damage is therefore useless. They'd become a lot more like Romero zombies, not so hard to kill but still extraordinarily dangerous since you can't afford even the slightest injury.