Big cat populations including the Amur tiger and Amur leopard are in jeopardy of extinction. Fewer than 550 Amur tigers and leopards remain in the wilderness of China and the Russian Far East today. Alongside threats posed by changing climates and human pressures, is another threat to cats that may sound familiar: dogs.
That’s right. A virus carried by the domestic dog may be one of the biggest threats to endangered wild felids like the Amur tiger.
According to University of Minnesota infectious disease ecologist Meggan Craft, Ph.D., who commented on the threat for the American Society for Microbiology’s journal mBio alongside University of Illinois wildlife pathologist Karen Terio, D.V.M., Ph.D., D.A.C.V.P., the magnitude of the threat depends on how you look at it.
“The biggest threat to big cat conservation as a whole is habitat loss. We don’t have enough space for the large cats and their prey. They need wild land.”
But in small populations, like that of the Amur tiger and leopard, “Infectious disease can be really detrimental,” said Craft.
For Amur tigers, canine distemper virus seems to be a high-risk threat. In recent research led by the Wildlife Conservation Society, Amur tigers were found to harbor the virus and develop neurologic disease, reducing their chances of successful survival in the wild.
This new evidence of canine distemper in Amur populations, alongside previous research documenting the disappearance of one-third of the Serengeti lion population in 1994 and the loss of cats in zoos due to canine distemper, led Terio and Craft to ask if the canine distemper virus was really more a carnivore distemper virus.
Perhaps domestic dogs carrying canine distemper do not just “spillover” the virus into other animal populations like raccoons, hyenas, and Amur tigers as previously thought, proposed Terio and Craft. Perhaps canine distemper transmission among different animal species in the same geographic area is completely normal. Perhaps it is part of normal disease ecology.
So has dog to cat disease transmission put entire species at risk historically? Scientists aren’t yet certain.
But the question of how to eliminate the threat of canine distemper to endangered populations remains.
Terio and Craft doubt vaccinating a few domestic dogs near big cat conservation areas will be enough to fully protect the cats from disease threats. Vaccinating the large wild cats themselves also falls short of a complete solution, partly because many other carnivore hosts can also transmit the virus.
Therefore, a calculated investigation into which carnivore populations can carry the virus has been called for to ensure all virus-carriers are identified and addressed.
Pet dogs, big cats and other carnivores are likely to make that list.
Craft’s research focuses on mathematical modeling of infectious diseases (like canine distemper) in animal populations. Her new research into how domestic dogs and wildlife interact in the Serengeti ecosystem of Tanzania is expected to strengthen understanding of just what it will take to protect Amur tigers, leopards, Serengeti lions and other endangered big cats … from dogs and more.