
When we had puppies around, and we had no separate kennelling for our lot, we restricted where we took our adults on exercise. We were lucky to live in the 'sticks' when doing litter, so although of course it only takes one dog (fox?), in the main our adults didn't meet up with other dogs in any case. There is a limit to how much anybody can protect their puppies/litters from however. We didn't do any shows when 'with pup' or go to any gatherings of other dogs. I know of one breeder who stupidly took one of her adults to a fun day - and brought back Kennel Cough with the result that although she did manage to save some of the litter, she did lose some. My puppies are in the kitchen (by around week 3 when a second 4 X 4 section is added to the original section to give them more room) but the sides of the box prevent nose to nose contact, even if the adults were interested!! So contact before external vaccination is limited. With mum, when she goes outside to empty, before she goes back in with the puppies, I wipe her feet and teats with a diluted antiseptic solution.
The natural immunity from mum, provided the puppies take the first milk (and I believe, that mum's boosters are current before being mated), should last for roughly 5 weeks after which it gradually drops until by around 8 weeks, it's felt safe to externally vaccinate, and the vaccination take.***
Best I can say is I haven't ever lost a puppy/puppies to some walked-in infection. Thankfully!!
When my puppies went outside, before being externally vaccinated, they went into an extended ex-pen which wasn't where our adults had been walking, or emptying.
Visitors - removed shoes and washed hands but fact is I tended not to allow touching early on. I didn't have people in early days, not because of the risk of infection but more because having strangers in to 'gawk' didn't do my bitch much good. People she knew - fine, but not strangers until the puppies were older and ready to be chosen for their new homes. With Bassets that didn't happen until they were over 6 weeks by which time their ears had begun to 'come down' and they looked more like 'Bassets' LOL.
*** "latest research shows mothers immunity lasting up to 14 weeks . for further information you may like to look at research by Dr Ron Shultz and the wsava "
That being the case, why does external vaccination, given from 8 weeks on (I had mine done at 10 weeks) actually 'take'. If there is any immunity there, as far as I'm aware, it is unlikely to take, and would be pointless - and the puppies at risk, after 14 weeks, because the external vac. hadn't been effective? Confused.com