do most puppies catch parvo after 4 months if they have not had their shots?

Not all puppies will catch parvo, even if they are exposed to it. In a shelter environment, I have seen some puppies out of a litter contract it and the others show no sickness at all. If your puppy has been exposed, watch for vomiting, diaharreah, change in personality, etc. Check out the AVMA website for more detailed information.

However, vaccinating your pup is the best answer to make sure that it does not contract it.

Why risk it? Parvo becomes dangerous very quickly. It's never a good idea to skimp on shots for puppies.

No, only if they have been around other dogs with parvo. Parvo is extremely bad.

probably,puppies r sensitive and they need their shots to get done when they are a month old .I know what i'm talking about i have a two months old dog

also it stays in the place were it was last for up to 12 months

Yes they can - vaccinations help prevent disease but they are not 100% full proof.