Symptoms of parvo are foul smelling bloody diarrhea, vomiting, fever and loss of appetite. http://www.petplace.com/dogs/parvoviral-enteritis/page1.aspx
If your dog is having seizures it may be due to another illness. Some dogs get what are known as idiopathic seizures which means that there is no known cause. The important thing to know about seizures are if they last more then ten minutes or happen two or more times in a twenty four hour period vet help should be sought immediately.
If the seizures are infrequent, once a month or so, then usually nothing is done. More frequency may require anti convulsant drugs.
There are dogs that are predisposed to seizures do to underlying illnesses like diabetes or epilepsy and for that reason you may want to have the dog checked.
Keep a log on the seizures, the dates , times, seizure activity(what the dog is doing during a seizure) ,and how long the seizure lasts so you have a baseline to bring to your vet.
Here is information on seizures that you may find helpful.