Can a dog have more then 1 kind of worm at a time?

Yes! Many types in fact, Tapeworm (usually looks like rice), roundworm (kind of like speghetti), hookworm and a few others. Of course they can have heart worms too which is in the heart-as it sounds.Most vets have dewormers that can get rid of many at once. The best bet is to have their stool checked under a microscope for eggs of the worms to know which ones they have.

There are many type of internal parasites. The best thing is to bring in a stool sample from your pet, collected from over a 2 day period. Take it to your Veterinarian to be tested. For Heartworms, you would need to bring your pet into the Vet to be tested with a blood test. It is very important that you test your dog for heartworms and then keep your pet on a once a month preventative, year around, if the test shows your pet negative for heartworms. Mosquitoes are the carriers of heartworms and they are everywhere.