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Ask a Vet: Is a Dog’s Voice Changing a Symptom of Rabies?

Voice change in dogs has many causes, but one is the deadliest known diseases for dogs and humans.

Dr. Eric Barchas  |  Sep 8th 2014


Several years ago I signed up for the U.S. Centers for Disease Control’s so-called “Clinician’s Outreach” mailing list. Members of the list receive updates from CDC about emergent disease threats. Obviously, one needn’t be a physician to subscribe. Anyone who is interested can sign up.

Over the years I have observed CDC’s response to a number of disease threats. I missed out on SARS, but I have seen the response to several scary strains of influenza as well as a number of food-borne E. coli outbreaks and the utterly horrifying Middle Eastern respiratory virus.

Generally I receive an email or two each month. But lately things have really taken off. Alerts have been coming in quickly and furiously. That’s because part of the world is in the midst of a serious epidemic. I’m talking about Ebola virus.

Ebola is a frightening thing. Symptoms initially are flu-like and vague, but then progress in a terrible fashion to a hemorrhagic fever. Uncontrolled bleeding may occur, leading to bruising, rashes, bloodshot eyes, and internal hemorrhage. Death may occur as a result of multiple organ dysfunction syndrome. There are no specific treatments for the disease; only supportive care is available to afflicted individuals. As I am writing this, about 2,500 people are suspected to have been infected in the current Ebola epidemic. The death rate has been approximately 50 percent.

Ebola absolutely is outrageously serious and scary. It has inspired shocking books (I remember reading The Coming Plague many years ago) and massive media coverage. But when it comes to frightening and deadly viruses, I can think of one that makes Ebola seem downright mild. Unlike Ebola, it has been around for almost all of human history, and has chronically impacted the human psyche. It is likely to have inspired legends of werewolves and vampires. It has featured prominently in literature ranging from Old Yeller to To Kill a Mockingbird. In 2010 it was estimated to have killed around 26,000 people, most of them children. Its fatality rate, until recently, was exactly 100 percent once symptoms developed, and to this day only a few people are known to have survived the disease once symptoms have started. The agony of the disease is horrific in ways that cannot be imagined. The disease does not merely ravage humans — our best friends also suffer in untold numbers.

The disease, of course, is rabies.

In the developed world we do not give much consideration to rabies. The canine rabies vaccine has largely eliminated the disease. The tens of thousands of people who die each year from rabies live almost exclusively in developing countries where dogs are not vaccinated. (Although many mammals can spread rabies to humans, dogs are by far the leading source of human rabies worldwide. Rabies is believed to be 100 percent fatal to dogs as well as humans.)

What does all of this have to do with most Dogster readers? Why should those of us who live in the United States spend time worrying about a disease that has been largely eliminated in our country?

I recently attended a lecture on rabies epidemiology. At the lecture, a public health official discussed the case of a dog who lived on the very modern San Francisco Peninsula.

The dog was born at a reputable breeding facility and adopted by a family at the standard two months of age. She received a high-quality rabies vaccine from a reputable manufacturer at the (then standard) four months of age. The trouble started about six months later.

Over a period of around 90 days the dog exhibited a serious problem with aggression. During that time she bit four members of the family that had adopted her, often without any sort of provocation. At least one family member was bitten in more than one instance. Late in the course of the problem she became sick, with poor appetite and intermittent lethargy. Her voice was noted to change.

As the aggression became unbearable for the family she was relinquished to animal control officials, and euthanasia was performed. Rabies testing is legally mandated in all dogs who are euthanized within 10 days of biting a human being. The dog therefore was tested and the result was positive. She was known to have bitten four people, and many others were potentially exposed. All were forced to undergo post-exposure rabies prophylaxis, which is expensive but life saving.

Believe it or not, the clue in this puzzle that most points to rabies is the dog’s change in voice. It turns out that a change in vocalization is the most consistent and common symptom of rabies in dogs.

However, please don’t panic if your dog’s voice changes. Although a change in voice may be the most consistent symptom of rabies, be aware that rabies is very far from the most consistent cause of a change in voice in dogs. Infectious or inflammatory laryngitis, polyps on the voice box, foreign objects in the area of the voice box, and tumors in the area are all phenomenally more common. I have assessed scores of dogs for voice changes, and have yet to identify a case that was even remotely suspicious for rabies.

But do be aware that sometimes subtle changes can be harbingers of serious problems. Veterinary assessment is always a good idea whenever something, even something minor, seems wrong with a dog.

The astute among you will have noticed that the dog in this story had a current rabies vaccine. Unfortunately, rabies vaccine standards are determined not by scientists or veterinarians but instead by state legislatures. Scientific evidence shows that a dog’s initial rabies vaccine often provides limited or temporary protection against the disease; it is the second vaccine (which usually is administered at one year of age) that more consistently renders dogs reliably immune. Owners of young dogs therefore may wish to consider an increased vaccination frequency for their pets.

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