So, how do these people prevent outbreaks of crypto running through their entire collection if they cohab?
I do think in general we are less strict with stuff over here, I'm pretty sure many people do wash water bowls with the same sponge all the time and many do not wash or disinfect in between every single snake handling. We do not all use separate feeding tubs for each snake either. Still I know about just one crypto outbreak in a bull snake collection over the past 7 years that I've been active in the Dutch snake world. But maybe I missed some or people keep them secret, I don't know.
For me it is common sense to separate an animal that seems not ok and that is co-habbed. If the ill one needs treatment, I treat the room mates too if the vet says it does no harm. If the vet says it is better to wait for symptoms in room mates, I wait for symptoms.
I myself did have a outbreak of another bacteria, but most of the victims were in a large rack with individual housed parents. I did keep juvies together with 2 or 3 at the time but none got infected.
Yet thinking back about snakes in my collection which got ill, in the period after the large outbreak I mentioned till now, I have to conclude that I had two cases of flagellata and one of upper respiratory infection (gopher snake). All three animals where housed separately (one was co-habbed a few months before the flagellata infection, both the other cornsnake and the gopher were never co-habbed).
I do keep a new snake alone for a few months first if it is intended to be co-habbed. I think any more serious breeder/keeper does that over here.
I do understand that not co-habbing and being very strict with hygiene is optimal for preventing outbreaks of infections. An any outbreak that can be prevented is important, but to me it does not look like being less strict and co-habbing increases the amount of cases significantly. I think that if outbreaks would have raged through Dutch collections, we would have changed our minds about co-habbing meanwhile.