Vaccinating Your Dog Also Protects Endangered Species
3 min read
When you take your dog to be vaccinated against distemper, you're probably thinking only about him. A 2022 scientific review, published in the journal Pathogens by researcher Rachel Wilkes, argues that this decision has a much wider reach: canine distemper is today one of the extinction threats for several endangered wild species, and the domestic dog is at the center of that story.
A virus that doesn't respect the barrier between species
Distemper is not exclusive to dogs. The review documents outbreaks with massive mortality in populations of lions (more than 85% of Serengeti lions were infected in the early 1990s, with a 30% loss of the population), Amur leopards, tigers, black-footed ferrets, and Caspian seals, among other species. They all share something: they are small, isolated populations, where a single outbreak can push an already vulnerable species one step closer to extinction.
Why the dog matters in this story
For decades it was assumed that controlling distemper in domestic dogs, the most numerous and manageable species, would be enough to stop transmission to wildlife. Mass vaccination campaigns in areas bordering protected zones (in Africa and India, for example) were designed under that logic. The review is clear in its conclusion: those campaigns did not work as expected. In the most studied case, the Serengeti lions, it was later shown that the virus did not arrive through dogs living near the park, but from other wild species that act as a reservoir of the virus independently.
This does not mean that vaccinating your dog is useless for wildlife, quite the opposite: it means the virus keeps circulating among multiple interconnected species at the same time (what researchers call a "metareservoir"), and that every link in that chain that gets cut, your dog included, reduces the total pressure on the ecosystems where dogs, urban wildlife, and endangered species coexist.
The problem on the wildlife side
The review devotes a good part of its content to explaining why vaccinating wildlife directly is much harder than vaccinating dogs: there is still no vaccine designed specifically for non-domestic species, modified live virus vaccines (the most effective in dogs) have caused the disease in several wild species instead of preventing it, and capturing solitary animals such as tigers or leopards to give periodic boosters is costly and, in some cases, ends up leaving them in permanent captivity. It is a problem veterinary science has not yet solved.
What is in your hands
Faced with such a large problem, the part that falls to each dog owner is the simplest of all: keeping the vaccination schedule complete and up to date. It is not an absolute guarantee (no study in this series presents it that way), but it is the only piece of this puzzle that a dog owner can directly control, and the science is clear that every unvaccinated dog is one more link in a chain that often ends much farther from home than we imagine.
Source: Wilkes RP. "Canine Distemper Virus in Endangered Species: Species Jump, Clinical Variations, and Vaccination." Pathogens. 2022;12(1):57. DOI: 10.3390/pathogens12010057. Published under a CC BY 4.0 license.