I'm sorry if you already responded but as you can see above I did not get it so I apologize that it did not come through.

There can be any number of reasons for the puppies to die. Testing the mom for parvo isn't really useful, the puppies would need to be tested. There are three forms of parvo infection:

1. Asymptomatic - No signs seen. Common in dogs over 1 year old and vaccinated dogs. They show no signs and just die.

2. Cardiac - Severe inflammation and necrosis (cell Death), of the heart muscle causes breathing difficulty and death in very young (less than 8 weeks of age) puppies.

3. Intestinal - This virus causes extreme damage to the intestinal tract, causing sloughing of the cells that line the tract. This can leave the patient open to secondary bacterial infection. Most of the affected dogs (85%) are less than one year old and between 6-20 weeks old -- before the full set of vaccinations can be given. The death rate from infection is reported to be 16-35% in this age group. This is the most common of the three and the one that most people are familiar with.

If the puppies do have it, the cardiac form sounds like the most likely. Again, testing the mom isn't going to be helpful. The vet needs to do a necropsy (autopsy) on one of the dead puppies and send tissue samples to a lab so they can figure out what is happening.

Of course, parvo isn't the only virus they could have (distemper, herpes, etc are also possible). They could have a septicemia (severe bacterial infection in the blood). They could also have a parasite infection. They could have a congenital problem (born with a problem with one or more of the internal organs).

So, just based on what you are saying there isn't much to point to one specific disease. The best bet at saving the other puppies is to have a vet do a necropsy on one of the deceased pups.

If you can't do that, the only other thing you can do is move the mom and pups to a different area. Completely bleach and clean the area they were in just in case there was something infectious there. And make sure mom is eating and producing milk.

Have you checked to make sure she is actually making enough milk? 13 puppies is a lot to feed so if there isn't enough milk then they may be starving to death. Just because the puppies are latching on and sucking doesn't mean they are actually getting any milk.

I hope this helps. Let me know if you have more questions. I will need to sign off in the next 15 to 20 minutes so if you respond after that it will be later today before I can get back to you.