Canine distemper is a very serious viral disease that affects a large body of domestic dogs as well as other animals, including species of wild dogs, foxes, pandas, coyotes, ferrets, skunks, wolves, racoons and many others. The disease which sometimes is labeled as hardpad disease in dogs has been affecting lions of Tanzania’s Serengeti National Park, and now the scientists have observed canine distemper to spread across multiple other species.
Transcontinental team of scientists have published a new study  in the journal of Proceedings of the National Academy of Sciences. The paper states that the transition of canine distemper viral disease to lions is no longer being sourced from domesticated dogs; other wild carnivores can now contribute as well.
Study of canine distemper in the wild
Findings of the new study demonstrate that in natural ecosystems, a deadly virus can jump between species and thrive, thereby threatening vulnerable animal populations, as stated in the press release.
“Our study shows that the dynamics of canine distemper virus are extremely complex, and a broadened approach – focusing not only on domestic dogs–is required if we are to control the disease among lions and other wild animal species,” said veterinary researcher Felix Lankester of Washington State University’s Paul G. Allen School for Global Animal Health, a co-author based in Tanzania.
In 1994, a mysterious neurological ailment wiped out 30-percent of the lion population in the Serengeti, one of the largest wildlife regions in the world. Scientists determined it was canine distemper, a disease previously thought to infect only dogs, coyotes and a small number of other mammals. Evidence suggested the lions had contracted the virus from dogs living in villages and settlements nearby. A domestic dog vaccination campaign was launched to curb the infection’s spread. It worked–among dogs, at least.
After analyzing three decades of blood serum data collected from lions and domestic dogs, the study’s researchers discovered that the virus continues to circulate in the lion population while significantly declining among dogs.
The dog’s role in spreading the disease appears to be shrinking, conclude the paper’s authors, an international team of veterinarians, disease ecologists, epidemiologists and mathematical biologists.
“Domestic dog populations immediately surrounding the Serengeti National Park are not the sole driver of canine distemper infections in lions, and its persistence is likely to involve a larger multi-host community,” they write.
Other species, including hyenas and jackals, are probably transmitting the disease and keeping it looming in the wild, they say. Consequently, outbreaks among lions and other already-threatened animals could occur at any time.
Researchers say more work is necessary to identify which species spread distemper and what triggers the spillovers. For example, it’s believed that an infected hyena or other carnivore feeding on a carcass can disperse the virus through mucus secretions to other predators at the same site.
A better understanding of canine distemper virus and its dynamics in the wild is necessary to effectively monitor and better control the disease among lions and other threatened animals, the scientists report.
- Mafalda Viana, Sarah Cleaveland, Jason Matthiopoulos, Jo Halliday, Craig Packer, Meggan E. Craft, Katie Hampson, Anna Czupryna, Andrew P. Dobson, Edward J. Dubovi, Eblate Ernest, Robert Fyumagwa, Richard Hoare, J. Grant C. Hopcraft, Daniel L. Horton, Magai T. Kaare, Theo Kanellos, Felix Lankester, Christine Mentzel, Titus Mlengeya, Imam Mzimbiri, Emi Takahashi, Brian Willett, Daniel T. Haydon, Tiziana Lembo. Dynamics of a morbillivirus at the domestic–wildlife interface: Canine distemper virus in domestic dogs and lions. Proceedings of the National Academy of Sciences, 2015; 201411623 doi: 10.1073/pnas.1411623112