DC,I think that depends on where you live and how you keep your dogs, all the lads that I've seen with parvo in their kennels have also been knee deep in sh*te and even after burning and replacing everything they've still had it back years later even after the jabs, look at Plummer he was a scruffy dirty bast**d,lost whole litters and adult dogs to it, I know lads in North Wales that kept kennels that were always sh*t high and it ravaged them, same in Crewe,the list is endless, keep clean kennels and feed the best and you will have the best out your dogs, mine live in these days and they are o