Dogs and wildlife share parvovirus say scientists
Canine parvovirus was first identified in the 1970’s and it quickly became a global pandemic responsible for the deaths of hundreds of thousands of dogs.
The arrival of a vaccine against the disease reduced the spread of canine parvovirus but it still poses a serious threat to unvaccinated dogs and puppies.
The study at Cornell University shows that it is relatively easy for a parvovirus from a wild carnivore such as a fox, to adapt to life in a dog and vice versa.
Andrew Allison, a postdoctoral associate at the Baker Institute for Animal Health in the College of Veterinary Medicine at Cornell University said: “This is the first systematic study to investigate which carnivore species in the wild are infected with canine parvovirus and how prevalent it may be.”
He said that virus was prevalent “everywhere the team looked.”
A team of scientists at Cornell has worked on canine parvovirus since it first emerged in the 1970s. The scientists became involved in the study and risks posed by wildlife infections after an outbreak of canine parvovirus killed several raccoons at a wildlife rehabilitation centre in Fairfax County, Virginia in 2007.
It’s pretty clear that some of these viruses are moving between wildlife and dogs
As the Cornell team began to investigate, they found outbreaks at wildlife centres across America.
“When I found the virus with the same genetic signatures in raccoons from Maine to Florida, that was the first indication that these weren’t isolated spill over events, and that the virus was widespread in raccoon populations,” Allison says.
Allison, Parrish and their colleagues tested samples from 852 wild carnivores from all over the United States, and they detected genetic sequences of the virus in 24 percent of coyotes, 19 percent of raccoons, and 67 percent of pumas.
Clues to how disease moves from animal to animal
The work provides clues as to how the virus moves from animal to animal, Allison explains. “Although these defined groups of related viruses in a single wild carnivore species tell you that the virus is likely being maintained in such wild species, there was also a tremendous amount of mixing between strains from wild and domestic animals,” he says.
Tests showed that many of these wildlife strains of canine parvovirus were unable to infect dogs, but the team suspected that since they were genetically very similar, it might be possible for a wildlife strain to adapt to life in a dog. They tested the hypothesis in the lab by growing different viruses in dog cell tissue cultures and tracking changes in the viruses over time.
Parvo virus is able to adapt to 'new host'
“Those experiments showed that the virus is able to adapt to a new host very quickly and that adaptation is occurring all the time,” says Colin Parish, a leading expert on the disease at Cornell.
He adds: “It’s pretty clear that some of these viruses are moving between wildlife and dogs.”
Parvovirus linked to Feline Panleukopenia
The team believes that their research gives some indication as to how the virus might have first emerged in the 1970s. Since it’s closely related to feline panleukopenia virus, scientists have long presumed that canine parvovirus must have crossed over from domestic cats into dogs, adapted, and triggered the pandemic.
“The widespread nature of canine parvovirus in many different carnivore species and its ability to readily adapt to a new host suggest that canine parvovirus may have originated from wild carnivores before jumping into dogs,” says Allison.
To check for disease risks to your pet in your area, go to our 'disease in my area' checker. For more advice about parvovirus in dogs and how you can protect your pets please speak to your veterinary surgeon.