The "what do you do while waiting for the vet" part of the question has not been answered and it is the part that saves puppies, so:
Fluids. That is the whole answer. Parvo does not usually kill by the virus itself, it kills by dehydration and by the secondary infection that gets in through a wrecked gut lining. A puppy with severe vomiting and bloody diarrhoea can be critically dehydrated in under twelve hours.
What you can do in the car / at 3am / while the clinic opens:
- Do not force water down a vomiting puppy. It comes straight back and you risk it going into the lungs.
- ORS, cool, in very small amounts — a syringe-full into the cheek pouch every fifteen minutes, not a bowl. Slow and constant beats a lot at once.
- Keep the pup warm. Parvo puppies get cold and a cold puppy stops absorbing anything.
- Isolate it from every other dog in the house immediately. This virus is unbelievably contagious.
What you must not do: human anti-diarrhoea medicine, milk, or "home remedies". I have seen someone give a parvo puppy phenyl-water on WhatsApp advice.
And the honest bit: with proper IV fluids and hospitalisation, survival is genuinely good — well over half, and much better in pups caught in the first day. Without a drip it is very poor. So the answer to "what do I do while waiting" is really "shorten the waiting". If your vet cannot see you tonight, find one who can.
Decontamination afterwards, because people move a new pup in a month later and it dies too. Parvo survives in soil and on surfaces for months and ordinary disinfectant does not touch it. Bleach at roughly 1:30 with water, thirty parts water to one part bleach, left on the surface for ten minutes. Anything porous — bedding, rope toys, a wooden kennel — you throw away. Wait months before bringing an unvaccinated pup onto ground where a parvo dog was.
