Rabies is a deadly virus that attacks the nervous system tissues, namely the dog's brain and spinal cord. All mammals, including humans can contract the virus.
While rabies is a devastating disease with a poor outcome, the good news is that rabies is a 100 percent preventable disease and also treatable, but only if treatment is initiated before the onset of symptoms.
Once the dog (or other mammal) starts manifesting clinical signs of rabies, the virus is lethal.
What is Rabies?
Rabies Lyssavirus is a virus known for attacking the nervous system preferentially. It derived from the Lyssavirus genus. It causes fatal polioencephalitis (inflammation of the brain and spinal cord, or more accurately their grey matter).
Rabies is usually transmitted through bite wounds inflicted by a rabid or infected animal. Virtually all mammals are susceptible to the rabies virus.
Rabies is a widespread disease. The only place in the World where there are no reported cases of rabies is Antarctica. Rabies is most frequently reported in Africa, Asia, and Latin America.
The CDC receives around 5000 reports about animal rabies cases per year. Over 90 percent of those cases are in wildlife.
Transmission of the Rabies Virus
The rabies virus is secreted in the saliva and therefore, the most common transmission form is through bite wounds. Namely, when an infected animal bites a dog it breaks its skin and the virus enters the dog’s bloodstream.
While the easiest and simplest transmission is when an infected animal bites another animal or human, this is not the only mode of transmission.
The virus can also be transmitted if an open wound is exposed to the saliva of an infected animal. For example, if a rabid dog licks the wound of another dog it can transmit the virus.
Organ transplantations, aerosol transmissions, and mucous membranes (mouth, nose, eyes) contaminations are also possible infection routes.
The incubation period (time the virus needs before it exerts its clinical signs) varies between ten days to up to one year, however, in dogs generally it occurs between two weeks to four months. The exact incubation length depends on several factors, including:
- The infection's site – if the bite is closer to the brain or spinal cord the virus will trigger clinical manifestation more quickly
- The severity of the bite
- Amount of virus spread into the bite wound.
Risk Factors and Predispositions
Theoretically, rabies can be passed from one pet dog to another. However, in practice, most rabies cases stem from exposure to wildlife reservoir animals like foxes, raccoons, and bats.
Therefore, the risk of contracting rabies is particularly high in dogs that, because of their lifestyle, they are more exposed to wild animals. This would include hunting dogs, dogs frequently taken on hikes, and dogs living in the countryside.
How to Tell if a Dog Has Rabies
The disease occurs in three stages and each stage manifests with different signs and symptoms.
Can a dog have rabies without symptoms? Technically yes, during the incubation period the dog has rabies, but it is not showing any clinical signs and symptoms. The clinical signs and symptoms become apparent once the incubation period is over.
During this first stage the dog experiences sudden and unusual behavior changes. In general, dogs that are quiet and calm become hyperactive and agitated, while dogs that are normally rambunctious and active, become shy and mellow.
The prodromal phase is short and usually lasts between two and three days. After this initial phase, the disease can take two forms – furious rabies and dumb rabies.
As the name implies, dogs with furious rabies tend to turn aggressive, easily hyper-excitable, and show ravenous, but abnormal appetite – eating and chewing inedible items such as stones, wood, or dirt.
Eventually, paralysis takes place and affected dogs can no longer eat or drink. Finally, the dog dies because the paralysis affects the lungs and diaphragm thus disabling breathing. Usually, dogs die in a violent seizure.
In dogs, this form is much more common than the previous. Dumb rabies manifests with progressive paralysis that starts with the dog's legs, facial distortion, and inability to swallow.
Based on the inability to swallow, dog owners often assume their dogs must have something stuck inside their throats or mouths. Eventually, the dog falls into a comatose state and then dies.
Did you know? Curiously, one of the most popular signs associated with rabies – hydrophobia (fear of water) does not occur in dogs. Hydrophobia is a sign of rabies in humans.
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A Word About Excessive Drooling
As seen, rabid dogs express a variety of clinical signs and symptoms like excessive drooling, fearfulness, aggression, staggering, paralysis, difficulty swallowing, and seizures.
Excessive drooling, or foaming at the mouth, is the most frequently depicted sign, but it is not present in all rabid dogs.
Namely, just because a dog is not foaming, it does not mean it is not rabid and vice versa – if a dog is foaming it does not mean it has rabies.
A Lack of Visible Bite Doesn't Mean No Bite!
Many dog owners assume that a dog with potential rabies should exhibit a bite wound that will be clearly visibile.
Here's the thing: one of the most common rabies carriers are bats. Although they are primarily active outdoors, bats can get inside and bite people and other animals while they sleep.
In these cases, the biting can be virtually painless and there can be no visible bite wound. Therefore, keeping your dog up to date on its rabies vaccination and bat-proofing your home is recommended.
Diagnosing and Treating Rabies in Dogs
When handling a potentially rabid dog extra caution is necessary because even the dog’s saliva is contagious and dangerous.
If a regularly vaccinated dog gets bitten by a rabid animal, its chances of contracting the virus are slim to none. However, the vet will recommend a booster immunization and monitoring for couple of days.
The outcome is much more complicated for dogs that are not vaccinated or not up to date on their vaccines. Sadly, there are no treatment options for rabid dogs.
Therefore, if a non-vaccinated dog is suspicious for having contracted rabies, it needs to be isolated for at least 10 days and closely monitored.
If the dog does not show symptoms during isolation it is considered to be free from the disease. If a dog starts showing signs it has to be euthanized.
Things are particularly complicated if your dog has never been vaccinated against rabies. In such cases, the dog will be quarantined and euthanized the moment it starts showing signs of rabies.
How long does rabies take to kill a dog? Most dogs die of rabies between one and two weeks after manifesting the first clinical signs and symptoms.
The final diagnosis can be set postmortem after analyzing parts of the dog’s nervous system under a microscope (the ideal tissue to test a dog for rabies is the brain).
Did you know? Some dogs can recover from and survive rabies. According to statistics, 14 percent of the dogs carrying the rabies virus can survive.
Rabies Prevention – is Vaccination Effective?
Luckily, rabies is 100 percent preventable disease. The cornerstone of prevention is vaccination. Dogs need to be regularly vaccinated – starting from when they are three to four months old and then every year or every three year, depending on the state’s regulations.
The vaccine is efficient only when administered before the virus enters the dog’s nervous system. Modern anti-rabies vaccines are safe and effective.
Although it is true that the main rabies reservoir is wildlife, there are reports about rabid domestic animals and pets. Just because your dog lives inside your home, does not mean that an infected animal cannot get inside and transmit the virus.
By protecting your indoor dog, you are indirectly protecting yourself and other people because people are more likely to come into contact with a domestic dog than a wildlife animal.
Therefore all dogs, regardless of their living circumstances – indoor, outdoor, or combined, need to be kept up-to-date on their rabies vaccination.
Some dog owners believe one rabies vaccine is good for the rest of the dog's life. Sadly, there is no such thing as a vaccine providing life-long immunity.
Puppies need to receive their first rabies vaccine when between three and four months old. They become protected 28 days after the vaccine is administered and this immunity lasts one year.
The puppies need a booster vaccine when they are around one year old. After that, based on the living region, dogs may need annual boosters or every three years.
As any other vaccine, the rabies vaccine is administered under the skin with a small needle. In most cases, dogs do not even realize when the needle is inserted into the skin.
Dogs that area uncomfortable around needles can be distracted with treats while the vet administers the vaccine. In some dogs, mild discomfort may develop after the vaccine but is transient and self-limiting.