(WAND) - Pet owners are being warned about the deadly nature of canine parvovirus and the need for vaccinations. 

The illness - also known as "parvo" - is one of the most serious viruses that can impact dogs. According to PetMD, it is very preventable if the animal is vaccinated. 

The website says parvo can live for a long time in an environment, is hard to kill, and is shed in large quantities by dogs who are infected. It was discovered in 1967. 

The parvo vaccine is considered a core vaccine for puppies and dogs because the virus is highly contagious. It spreads through urine or feces. 

Northgate Pet Clinic in Decatur said if a person's dog isn't yet vaccinated, now is the time. 

"Usually within an hour or two or a day or two, you may have some loose stool diarrhea, or vomit, and then that usually turns into bleeding blood," said Dr. Larry Baker of Northgate. "There's a lot of blood in the stool or blood in the vomit. That's because the intestine is being destroyed." 

To protect pets, Northgate is offering a parvo vaccination clinic at Rural King in Mt. Zion on Saturday. It runs from 10 a.m. to noon, and no appointment is necessary.Â