When canine parvovirus first emerged in 1978, it caused a global pandemic in which hundreds of thousands of dogs are thought to have died. Since then, the virus has occasionally shown up in wild animals, but these were considered a result of small-scale spillovers from dog populations.
A new study by Andrew Allison and Colin Parrish of the Baker Institute for Animal Health at Cornell University's College of Veterinary Medicine and others shows that many wild carnivores actually carry the virus, and that it is relatively easy for a parvovirus from a wild carnivore to adapt to life in a dog and vice versa.
"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," says Allison, a postdoctoral associate. "Surprisingly, it was everywhere we looked."
Parrish's lab has worked on canine parvovirus since it first emerged, and he and Allison became involved in wildlife infections after a 2007 outbreak of canine parvovirus killed several raccoons at a wildlife rehabilitation facility in Fairfax County, Virginia. Until then, it was not known that raccoons could be infected with the virus, but when they and their colleagues began to investigate, they found outbreaks at wildlife rehabilitation shelters all over the country. "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 spillover events, and that the virus was widespread in raccoon populations," Allison says.