Have you been up to date with your worming?
You have to treat your dog regularly.
Id purchase an all worm tablets or the drops you put behind their shoulder balds from your vet (they are only a preventative).
And get your dog checked out at the same time. Because The longer you have let this go the bigger the problem and the worms are inside your furry friend. Its only going to get worse if not done soon.
The vet will give you medication that will kill the worms that are growing in your dog.
And then keep up with the "All worm" To pro-vent it from happening again.
Yuck just thinking about those worms.
Do the best for your dog. :)