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Ask a Vet: Should Dogs Exposed to Ebola Be Euthanized?

Spanish authorities euthanized a dog owned by an Ebola patient. Was their action justified?

Dr. Eric Barchas  |  Oct 14th 2014


For at least a couple of decades I have had only a minimal amount of respect for the mainstream media. The reason for this is simple. I have been interviewed by news outlets many times. My words invariably have been contorted, taken out of context, or parsed in a way that sometimes renders my message the opposite of what I intended, and at other times makes me look ridiculous by making the quote unintelligible.

I therefore wonder how a group of people that reliably mucks up simple quotes by simple guys like me can be expected to get really big stories right.

And there is another thing. Regardless of one’s political views, I believe the media, whose job ostensibly is to report the news, instead spends a great deal of time creating news out of nothing (think Paris Hilton) or relentlessly promoting certain stories over others that might be more newsworthy.

For instance, remember the massive subway crash that happened in Washington, D.C., in June, 2009? When the news broke I took an immediate interest. Two red line trains had crashed. My sister and brother-in-law lived on the red line, and I had ridden it many times. I wanted details.

I never got those details, however, because within a few hours of the crash Michael Jackson died. It seemed like the entire news industry dropped everything, and the subway crash was forgotten.

Move the calendar up to 2014 and the mainstream media again went on a feeding frenzy. All summer long the media, and especially NPR, were obsessed with the thousands of unaccompanied migrant children reaching the U.S. border.

I feel great sympathy for those poor children, but after being the main thing on the media’s mind for months, they seem to have disappeared from the public consciousness. The Ebola breakout in West Africa began to nudge the children out of the limelight at the end of the summer. And now Ebola has reached the shores of Europe and the USA, the children have been completely forgotten.

The current media frenzy over and public reaction to Ebola reminds me a bit of AIDS in the 1980s. Then, a mysterious disease was killing people and was spreading in an unknown fashion. There was wild talk of mass quarantines, and some health care workers refused to treat AIDS patients.

We learned with time that the extreme initial reaction to AIDS was completely unfounded. As more was learned about the virus and its low transmissibility the panic subsided.

Fortunately we already know more about Ebola than we did about AIDS in the early days. Unfortunately, some of the news is bad: For instance, Ebola is far more contagious than HIV (although Ebola still isn’t highly contagious). And, like HIV, Ebola appears to have a zoonotic component.

Zoonotic diseases are those that can spread from animals to humans and vice versa. Bats are known to carry Ebola without showing symptoms. They are probably the reservoir hosts in the wild. Monkeys and primates (including humans) can contract and be sickened by the virus.

Most Ebola outbreaks are thought to have been sparked by human consumption of bush meat derived from wild forest animals. However, once the infection gets going, human-to-human transmission drives the epidemic.

But what about dogs? Can they contract the disease? Could they spread it to humans? These questions have led to a great deal of news in Spain.

A Spanish nurse recently contracted Ebola after treating a patient who died from the virus. Spanish authorities wanted to euthanize her dog because they feared that the dog might spread the disease. This sparked significant protest in support of the poor dog, who was euthanized anyway.

Are the actions of the Spanish authorities in any way reasonable? Since Ebola can only survive outside of infected individuals (or their blood) for a few hours, what risk could the dog pose?

It is my opinion that the dog poses minimal, or possibly even negligible risk. But unfortunately, there is a theoretical risk. A paper published in 2005 found that up to 32 percent of dogs exposed to Ebola during an earlier outbreak in Gabon developed antibodies to the virus.

Exposure alone generally is not sufficient to cause antibodies to develop. In general, an infection must occur. The study therefore implied that dogs could become infected with Ebola. There is no evidence to date that dogs can be sickened by the virus (in fact, the authors of the study reached the conclusion that “putative” canine Ebola infection is asymptomatic), but one burning question emerges from the study: Could dogs shed the virus and therefore become a risk to humans?

The answer is probably not. The epidemiology of Ebola has been studied quite extensively, and canine vectors do not appear to play a significant role, or even any role at all.

However, probably is not the same as definitely. There has not been sufficient research to rule out the possibility that dogs exposed to the virus could pose a risk to humans. As I’m sure you’re aware, Ebola is an incredibly scary disease. Public health officials are acting under a media microscope, and they’re not in any mood to take chances.

So why not quarantine the Spanish dog instead of killing him? It certainly sounds at first glance like the better option. Humans are known to incubate the virus for up to 21 days. If someone is exposed and he hasn’t become sick within three weeks he’s likely in the clear.

Ebola in dogs, however, is a much more of a mystery. At this time they appear capable of becoming infected, and they don’t appear to get sick. But things such as incubation period (which determines quarantine length) and virus shedding (which determines threat to humans) are completely unknown.

I picture a Spanish health official doing the following sort of risk benefit analysis with internal thought processes going something like this: “It is most likely that the dog poses no risk to people. In that event, if the dog’s life is spared then some protesters will be appeased and I can go about my life. But in another scenario, which has an infinitesimal probability, the dog might spread the disease to humans should his life be spared. In that case people could die, a Spanish epidemic could result, I would be disgraced, and my career would be over.”

Decision made. Poor dog.

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